MSc de Jong

1. An Ultrasound Matrix Transducer for High-Frame-Rate 3-D Intra-cardiac Echocardiography
   dos Santos, Djalma Simões; Ossenkoppele, Boudewine; Hopf, Yannick M.; Soozande, Mehdi; Noothout, Emile; Vos, Hendrik J.; Bosch, Johan G.; Pertijs, Michiel A.P.; Verweij, Martin D.; de Jong, Nico;
   Ultrasound in Medicine \& Biology,
   Volume 50, Issue 2, pp. 285--294, February 2024. DOI: 10.1016/j.ultrasmedbio.2023.11.001

2. A 125μm-Pitch-Matched Transceiver ASIC with Micro-Beamforming ADC and Multi-Level Signaling for 3-D Transfontanelle Ultrasonography
   Peng Guo; Fabian Fool; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
   IEEE Journal of Solid-State Circuits,
   pp. 1--14, 2024. early access. DOI: 10.1109/JSSC.2024.3355854

3. A 2000-Volumes/s 3D Ultrasound Imaging Chip with Monolithically-Integrated 11.7x23.4mm2 2048-Element CMUT Array and Arbitrary-Wave TX Beamformer
   Nuriel N.M. Rozsa; Zhao Chen; Taehoon Kim; Peng Guo; Yannick Hopf; Jason Voorneveld; Djalma Simoes dos Santos; Emile Noothout; Zu-Yao Chang; Chao Chen; Vincent A. Henneken; Nico de Jong; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Michiel A. P. Pertijs;
   In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
   2024. Accepted.

4. A Pitch-matched Low-noise Analog Front-end with Accurate Continuous Time-gain Compensation for High-density Ultrasound Transducer Arrays
   Peng Guo; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
   IEEE Journal of Solid-State Circuits,
   Volume 58, Issue 6, pp. 1693--1705, June 2023. DOI: 10.1109/jssc.2022.3200160

5. A 1.2 mW/Channel Pitch-Matched Transceiver ASIC Employing a Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3-D Ultrasound Imaging
   Peng Guo; Fabian Fool; Zu-Yao Chang; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Nico de Jong; Martin D. Verweij; Michiel A. P. Pertijs;
   IEEE Journal of Solid-State Circuits,
   Volume 58, Issue 9, pp. 2607--2618, September 2023. DOI: 10.1109/jssc.2023.3271270

6. A Pitch-Matched High-Frame-Rate Ultrasound Imaging ASIC for Catheter-Based 3D Probes
   Yannick M. Hopf; Djalma Simoes dos Santos; Boudewine W. Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
   IEEE Journal of Solid-State Circuits,
   Volume 59, Issue 2, pp. 476--491, February 2023. DOI: 10.1109/JSSC.2023.3299749
   
   Abstract: ...

   This article presents an application-specific integrated circuit (ASIC) for catheter-based 3-D ultrasound imaging probes. The pitch-matched design implements a comprehensive architecture with high-voltage (HV) transmitters, analog front ends, hybrid beamforming analog-to-digital converters (ADCs), and data transmission to the imaging system. To reduce the number of cables in the catheter while maintaining a small footprint per element, transmission (TX) beamforming is realized on the chip with a combination of a shift register (SR) and a row/column (R/C) approach. To explore an additional cable-count reduction in the receiver part of the design, a channel with a combination of time-division multiplexing (TDM), subarray beamforming, and multi-level pulse amplitude modulation (PAM) data transmission is also included. This achieves an 18-fold cable-count reduction and minimizes the power consumption in the catheter by a load modulation (LM) cable driver. It is further explored how common-mode interference can limit beamforming gain and a strategy to reduce its impact with local regulators is discussed. The chip was fabricated in TSMC 0.18-μm HV BCD technology and a 2-D PZT transducer matrix of 16 × 18 elements with a pitch of 160 μm and a center frequency of 6 MHz was manufactured on the chip. The system can generate all required TX patterns at up to 30 V, provides quick settling after the TX phase, and has an reception (RX) power consumption of only 1.12 mW/element. The functionality and operation of up to 1000 volumes/s have been demonstrated in electrical and acoustic imaging experiments.

7. An ultrasound matrix transducer for high-frame-rate 3D intracardiac echocardiography
   Djalma Simoes dos Santos; Boudewine Ossenkoppele; Yannick M. Hopf; Mehdi Soozande; Emile Noothout; Hendrik J. Vos; Johan G. Bosch; Michiel A. P. Pertijs; Martin D. Verweij; Nico de Jong;
   Ultrasound in Medicine \& Biology,
   2023. accepted.
   
   Abstract: ...

   Objective: This paper presents the development of an ultrasound matrix transducer prototype for high frame rate three-dimensional (3D) intracardiac echocardiography (ICE). Methods: The matrix array consists of 16 ×18 lead zirconate titanate (PZT) elements with a pitch of 160 µm × 160 µm built on top of an application-specific integrated circuit (ASIC) that generates transmission signals and digitizes the received signals. To reduce the number of cables in the catheter to a feasible number, we implement subarray beamforming and digitization in receive and use a combination of time-division multiplexing and pulse amplitude modulation data transmission, achieving an 18-fold reduction. The proposed imaging scheme employs seven fan-shaped diverging transmit beams operating at a pulse repetition frequency of 7.7 kHz to obtain a high frame rate. The performance of the prototype is characterized and its functionality is fully verified. Results: The transducer exhibits a transmit efficiency of 28 Pa/V at 5 cm per element and a bandwidth of 60% in transmission. In receive, a dynamic range of 80 dB is measured with a minimum detectable pressure of 10 Pa per element. The element yield of the prototype is 98%, indicating the efficacy of the manufacturing process. The transducer is capable of imaging at a frame rate of up to 1000 volumes/s and is intended to cover a volume of 70° × 70° × 10 cm. Conclusion: These advanced imaging capabilities have the potential to support complex interventional procedures and enable full-volumetric flow, tissue, and electro-mechanical wave tracking in the heart.

8. A Pitch-Matched Transceiver ASIC for 3D Ultrasonography with Micro-Beamforming ADCs based on Passive Boxcar Integration and a Multi-Level Datalink
   Guo, P.; Chang, Z. Y.; Noothout, E.; Vos, H. J.; Bosch, J. G.; de Jong, N.; Verweij, M. D.; Pertijs, M. A. P.;
   In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
   IEEE, pp. 1-2, 2023. accepted.

9. A prototype matrix transducer for high frame rate 3D intracardiac echography
   D. Santos; Y. Hopf; B. Ossenkoppele; J. Bosch; R. Vos; M. Pertijs; N. de Jong; M. Verweij;
   In Proc. IEEE International Ultrasonics Symposium (IUS),
   2023. abstract, accepted.

10. Measurement of Pipe and Fluid Properties with a Matrix Array-based Ultrasonic Clamp-on Flow Meter
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; A. Sabbadini; N. de Jong; M. A. P. Pertijs; M. D. Verweij;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 69, Issue 1, pp. 309--322, January 2022. DOI: 10.1109/TUFFC.2021.3111710

11. A Compact Integrated High-Voltage Pulser Insensitive to Supply Transients for 3D Miniature Ultrasound Probes
    Yannick M. Hopf; Boudewine Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
    IEEE Solid-State Circuits Letters,
    Volume 5, pp. 166--169, 2022. DOI: 10.1109/lssc.2022.3180071
    
    Abstract: ...

    In this paper, a compact high-voltage (HV) transmit circuit for dense 2D transducer arrays used in 3D ultrasonic imaging systems is presented. Stringent area requirements are addressed by a unipolar pulser with embedded transmit/receive switch. Combined with a capacitive HV level shifter, it forms the ultrasonic HV transmit circuit with the lowest reported HV transistor count and area without any static power consumption. The balanced latched-based level shifter implementation makes the design insensitive to transients on the HV supply caused by pulsing, facilitating application in probes with limited local supply decoupling, such as imaging catheters. Favorable scaling through resource sharing benefits massively arrayed architectures while preserving full individual functionality. A prototype of 8 x 9 elements was fabricated in TSMC 0.18 μm HV BCD technology and a 160 μm x 160 μm PZT transducer matrix is manufactured on the chip. The system is designed to drive 65 V peak-to-peak pulses on 2 pF transducer capacitance and hardware sharing of 6 elements allows for an area of only 0.008 mm2 per element. Electrical characterization as well as acoustic results obtained with the 6 MHz central frequency transducer are demonstrated.

12. Imaging Scheme for 3-D High Frame Rate Intracardiac Echography: a Simulation Study
    M. Soozande; B. Ossenkoppele; Y. Hopf; M. Pertijs; M. Verweij; N. de Jong; H. Vos; J. Bosch;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 69, Issue 10, pp. 2862--2874, October 2022. DOI: 10.1109/TUFFC.2022.3186487
    
    Abstract: ...

    Atrial fibrillation is the most common cardiac arrhythmia, and normally treated by RF ablation. Intracardiac echography (ICE) is widely employed during RF ablation procedures to guide the electrophysiologist in navigating the ablation catheter, although only 2-D probes are currently clinically used. A 3-D ICE catheter would not only improve visualization of the atrium and ablation catheter, it might also provide 3-D mapping of the electromechanical wave propagation pattern, which represents the mechanical response of cardiac tissue to electrical activity. The detection of this electromechanical wave needs 3-D high frame rate imaging, which is generally only realizable in trade-off with channel count and image quality. In this simulation-based study, we propose a high volume rate imaging scheme for a 3-D ICE probe design that employs 1-D micro-beamforming in elevation direction. Such probe can achieve a high frame rate while reducing the channel count sufficiently for realization in a 10-Fr catheter. To suppress the grating-lobe artifacts associated with micro-beamforming in elevation direction, a limited number of fan-shaped beams with a wide azimuthal and narrow elevational opening angle are sequentially steered to insonify slices of the region of interest. An angular weighted averaging of reconstructed sub-volumes further reduces the grating lobe artifacts. We optimize the transmit beam divergence and central frequency based on the required image quality for electromechanical wave imaging (EWI). Numerical simulation results show that a set of 7 fan-shaped transmission beams can provide a frame rate of 1000 Hz and a sufficient spatial resolution to visualize the electromechanical wave propagation on a large 3-D surface.

13. Design and Proof-of-Concept of a Matrix Transducer Array for Clamp-on Ultrasonic Flow Measurements
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; E. C. Noothout; N. de Jong; M. A. P. Pertijs; M. D. Verweij;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 69, Issue 8, pp. 2555--2568, August 2022. DOI: 10.1109/tuffc.2022.3186170
    
    Abstract: ...

    Common clamp-on ultrasonic flow meters consist of two single-element transducers placed on the pipe wall. Flow speed is measured non-invasively, i.e. without interrupting the flow and without perforating the pipe wall, which also minimizes safety risks and avoids pressure drops inside the pipe. However, before metering, the transducers have to be carefully positioned along the pipe axis to correctly align the acoustic beams and obtain a well-calibrated flow meter. This process is done manually, is dependent on the properties of the pipe and the liquid, does not account for pipe imperfections, and becomes troublesome on pipelines with an intricate shape. Matrix transducer arrays are suitable to dynamically steer acoustic beams and realize self-alignment upon reception, without user input. In this work, the design of a broadband 37x17 matrix array (center frequency of 1 MHz) to perform clamp-on ultrasonic flow measurements over a wide range of liquids (c = 1000 - 2000m/s, α≤1 dB/MHz.cm) and pipe sizes is presented. Three critical aspects were assessed: efficiency, electronic beam steering, and wave mode conversion in the pipe wall. A prototype of a proof-of-concept flow meter consisting of two 36-element linear arrays (center frequency of 1.1 MHz) was fabricated and placed on a 1 mm-thick, 40 mm-inner diameter stainless steel pipe in a custom-made flow loop filled with water. At resonance, simulated and measured efficiencies in water of the linear arrays compared well: 0.88 kPa/V and 0.81 kPa/V, respectively. Mean flow measurements were achieved by electronic beam steering of the acoustic beams and using both compressional and shear waves generated in the pipe wall. Correlation coefficients of R2 > 0.99 between measured and reference flow speeds were obtained, thus showing the operational concept of an array-based clamp-on ultrasonic flow meter.

14. A Pitch-Matched Transceiver ASIC with Shared Hybrid Beamforming ADC for High-Frame-Rate 3D Intracardiac Echocardiography
    Yannick M. Hopf; Boudewine W. Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 57, Issue 11, pp. 3228--3242, November 2022. DOI: 10.1109/jssc.2022.3201758
    
    Abstract: ...

    In this article, an application-specific integrated circuit (ASIC) for 3-D, high-frame-rate ultrasound imaging probes is presented. The design is the first to combine element-level, high-voltage (HV) transmitters and analog front-ends, subarray beamforming, and in-probe digitization in a scalable fashion for catheter-based probes. The integration challenge is met by a hybrid analog-to-digital converter (ADC), combining an efficient charge-sharing successive approximation register (SAR) first stage and a compact single-slope (SS) second stage. Application in large ultrasound imaging arrays is facilitated by directly interfacing the ADC with a charge-domain subarray beamformer, locally calibrating interstage gain errors and generating the SAR reference using a power-efficient local reference generator. Additional hardware-sharing between neighboring channels ultimately leads to the lowest reported area and power consumption across miniature ultrasound probe ADCs. A pitch-matched design is further enabled by an efficient split between the core circuitry and a periphery block, the latter including a datalink performing clock data recovery (CDR) and time-division multiplexing (TDM), which leads to a 12-fold total channel count reduction. A prototype of 8×9 elements was fabricated in a TSMC 0.18- μm HV BCD technology and a 2-D PZT transducer matrix with a pitch of 160μm , and a center frequency of 6 MHz was manufactured on the chip. The imaging device operates at up to 1000 volumes/s, generates 65-V transmit pulses, and has a receive power consumption of only 1.23 mW/element. The functionality has been demonstrated electrically as well as in acoustic and imaging experiments.

15. Algorithm to Correct Measurement Offsets Introduced by Inactive Elements of Transducer Arrays in Ultrasonic Flow Metering
    Jack Massaad; Paul L. M. J. van Neer; Douwe M. van Willigen; Michiel A. P. Pertijs; Nicolaas de Jong; Martin D. Verweij;
    Sensors,
    Volume 22, Issue 23, pp. 2--14, November 2022. DOI: 10.3390/s22239317
    
    Abstract: ...

    Ultrasonic flow meters (UFMs) based on transducer arrays offer several advantages. With electronic beam steering, it is possible to tune the steering angle of the beam for optimal signal-tonoise ratio (SNR) upon reception. Moreover, multiple beams can be generated to propagate through different travel paths, covering a wider section of the flow profile. Furthermore, in a clamp-on configuration, UFMs based on transducer arrays can perform self-calibration. In this manner, userinput is minimized and measurement repeatability is increased. In practice, transducer array elements may break down. This could happen due to aging, exposure to rough environments, and/or rough mechanical contact. As a consequence of inactive array elements, the measured transit time difference contains two offsets. One offset originates from non-uniform spatial sampling of the generated wavefield. Another offset originates from the ill-defined beam propagating through a travel path different from the intended one. In this paper, an algorithm is proposed that corrects for both of these offsets. The algorithm also performs a filtering operation in the frequency-wavenumber domain of all spurious (i.e., flow-insensitive) wave modes. The advantage of implementing the proposed algorithm is demonstrated on simulations and measurements, showing improved accuracy and precision of the transit time differences compared to the values obtained when the algorithm is not applied. The proposed algorithm can be implemented in both in-line and clamp-on configuration of UFMs based on transducer arrays.
    
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16. A Tiled Ultrasound Matrix Transducer for Volumetric Imaging of the Carotid Artery
    dos Santos, Djalma Simões; Fool, Fabian; Mozaffarzadeh, Moein; Shabanimotlagh, Maysam; Noothout, Emile; Kim, Taehoon; Rozsa, Nuriel; Vos, Hendrik J.; Bosch, Johan G.; Pertijs, Michiel A. P.; Verweij, Martin D.; de Jong, Nico;
    Sensors,
    Volume 22, Issue 24, pp. 1--23, 2022. DOI: 10.3390/s22249799
    
    Abstract: ...

    High frame rate three-dimensional (3D) ultrasound imaging would offer excellent possibilities for the accurate assessment of carotid artery diseases. This calls for a matrix transducer with a large aperture and a vast number of elements. Such a matrix transducer should be interfaced with an application-specific integrated circuit (ASIC) for channel reduction. However, the fabrication of such a transducer integrated with one very large ASIC is very challenging and expensive. In this study, we develop a prototype matrix transducer mounted on top of multiple identical ASICs in a tiled configuration. The matrix was designed to have 7680 piezoelectric elements with a pitch of 300 μm × 150 μm integrated with an array of 8 × 1 tiled ASICs. The performance of the prototype is characterized by a series of measurements. The transducer exhibits a uniform behavior with the majority of the elements working within the −6 dB sensitivity range. In transmit, the individual elements show a center frequency of 7.5 MHz, a −6 dB bandwidth of 45%, and a transmit efficiency of 30 Pa/V at 200 mm. In receive, the dynamic range is 81 dB, and the minimum detectable pressure is 60 Pa per element. To demonstrate the imaging capabilities, we acquired 3D images using a commercial wire phantom.
    
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17. Measurement of pipe and liquid parameters using the beam steering capabilities of array-based clamp-on ultrasonic flow meters
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; M. A. P. Pertijs; N. de Jong; M. D. Verweij;
    Sensors,
    Volume 22, Issue 14, pp. 5068, July 2022. DOI: 10.3390/s22145068
    
    Abstract: ...

    Clamp-on ultrasonic flow meters (UFMs) are installed on the outside of the pipe wall. Typically, they consist of two single-element transducers mounted on angled wedges, which are acoustically coupled to the pipe wall. Before flow metering, the transducers are placed at the correct axial position by manually moving one transducer along the pipe wall until the maximum amplitude of the relevant acoustic pulse is obtained. This process is time-consuming and operator-dependent. Next to this, at least five parameters of the pipe and the liquid need to be provided manually to compute the flow speed. In this work, a method is proposed to obtain the five parameters of the pipe and the liquid required to compute the flow speed. The method consists of obtaining the optimal angles for different wave travel paths by varying the steering angle of the emitted acoustic beam systematically. Based on these optimal angles, a system of equations is built and solved to extract the desired parameters. The proposed method was tested experimentally with a custom-made clamp-on UFM consisting of two linear arrays placed on a water-filled stainless steel pipe. The obtained parameters of the pipe and the liquid correspond very well with the expected (nominal) values. Furthermore, the performed experiment also demonstrates that a clamp-on UFM based on transducer arrays can achieve self-alignment without the need to manually move the transducers.

18. A Pitch-Matched ASIC with Integrated 65V TX and Shared Hybrid Beamforming ADC for Catheter-Based High-Frame-Rate 3D Ultrasound Probes
    Y. Hopf; B. Ossenkoppele; M. Soozande; E. Noothout; Z. Y. Chang; C. Chen; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
    February 2022. DOI: 10.1109/ISSCC42614.2022.9731597
    
    Abstract: ...

    With applications moving to 3D imaging, catheter-based ultrasound probes need to reach a new level of integration. This paper presents the first chip to combine high-voltage transmitters, analog front-ends, micro-beamforming, digitization and transducers, enabling high-frame-rate 3D imaging. Its pitch-matched architecture, made possible by a shared SAR/slope ADC that is 4x smaller and consumes 1.5x less power than the prior art, makes it a scalable solution for future digital imaging catheters.

19. A 1.2mW/channel 100μm-Pitch-Matched Transceiver ASIC with Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3D Ultrasound Imaging
    P. Guo; F. Fool; E. Noothout; Z. Y. Chang; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
    February 2022. DOI: 10.1109/ISSCC42614.2022.9731784

20. Transceiver ASIC Design for High-Frame-Rate 3D Intracardiac Echocardiography
    Yannick M. Hopf; Boudewine Ossenkoppele; Mehdi Soozande; Emile Noothout; Zu-Yao Chang; Chao Chen; Hendrik J. Vos; Johan G. Bosch; Martin D. Verweij; Nico de Jong; Michiel A. P. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    2022.

21. Large Matrix array aperture for 3D vascular imaging capture
    Q. Colas; C. Bantignies; M. Perroteau; N. Porcher; S. Vassal; B. Guérif; T. Kim; J. G. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs; G. Férin; M. Flesch;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    2022.

22. Automated Characterization of Matrix Transducer Arrays using the Verasonics Imaging System
    Djalma Simoes dos Santos; Fabian Fool; Taehoon Kim; Emile Noothout; Nuriel Rozsa; Hendrik J. Vos; Johan G. Bosch; Michiel A. P. Pertijs; Martin D. Verweij; Nico de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    2022.

23. Automated Characterization of Matrix Transducer Arrays using the Verasonics Imaging System
    Djalma Simoes dos Santos; Fabian Fool; Taehoon Kim; Emile Noothout; Nuriel Rozsa; Hendrik J. Vos; Johan G. Bosch; Michiel A. P. Pertijs; Martin D. Verweij; Nico de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    2022.

24. Large Matrix array aperture for 3D vascular imaging capture
    Q. Colas; C. Bantignies; M. Perroteau; N. Porcher; S. Vassal; B. Guérif; T. Kim; J. G. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs; G. Férin; M. Flesch;
    In Smart Systems Integration Conference,
    2022. abstract.

25. Design of an Ultrasound Transceiver ASIC with a Switching-Artifact Reduction Technique for 3-D Carotid Artery Imaging
    T. Kim; F. Fool; D. Simoes dos Santos; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    Sensors,
    Volume 21, Issue 1, pp. 150, January 2021. DOI: 10.3390/s21010150
    
    Abstract: ...

    This paper presents an ultrasound transceiver application-specific integrated circuit (ASIC) directly integrated with an array of 12 × 80 piezoelectric transducer elements to enable next-generation ultrasound probes for 3D carotid artery imaging. The ASIC, implemented in a 0.18 µm high-voltage Bipolar-CMOS-DMOS (HV BCD) process, adopted a programmable switch matrix that allowed selected transducer elements in each row to be connected to a transmit and receive channel of an imaging system. This made the probe operate like an electronically translatable linear array, allowing large-aperture matrix arrays to be interfaced with a manageable number of system channels. This paper presents a second-generation ASIC that employed an improved switch design to minimize clock feedthrough and charge-injection effects of high-voltage metal–oxide–semiconductor field-effect transistors (HV MOSFETs), which in the first-generation ASIC caused parasitic transmissions and associated imaging artifacts. The proposed switch controller, implemented with cascaded non-overlapping clock generators, generated control signals with improved timing to mitigate the effects of these non-idealities. Both simulation results and electrical measurements showed a 20 dB reduction of the switching artifacts. In addition, an acoustic pulse-echo measurement successfully demonstrated a 20 dB reduction of imaging artifacts.
    
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26. A Transceiver ASIC for a Single-Cable 64-Element Intra-Vascular Ultrasound Probe
    D. van Willigen; J. Janjic; E. Kang; Z. Y. Chang; E. Noothout; M. Verweij; N. de Jong; M. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 56, Issue 10, pp. 3157-3166, October 2021. DOI: 10.1109/jssc.2021.3083217
    
    Abstract: ...

    This article presents an application-specific integrated circuit (ASIC) designed for intra-vascular ultrasound imaging that interfaces 64 piezoelectric transducer elements to an imaging system using a single micro-coaxial cable. Thus, it allows a single-element transducer to be replaced by a transducer array to enable 3-D imaging. The 1.5-mm-diameter ASIC is intended to be mounted at the tip of a catheter, directly integrated with a 2-D array of piezoelectric transducer elements. For each of these elements, the ASIC contains a high-voltage (HV) switch, allowing the elements to transmit an acoustic wave in response to an HV pulse generated by the imaging system. A low-noise amplifier then amplifies the resulting echo signals and relays them as a signal current to the imaging system, while the same cable provides a 3-V supply. Element selection and other settings can be programmed by modulating configuration data on the supply, thus enabling full synthetic aperture imaging. An integrated element test mode measures the element capacitance to detect bad connections to the transducer elements. The ASIC has been fabricated in a 0.18-μm HV CMOS technology and consumes only 6 mW in receive. Electrical measurements show correct switching of 30-V transmit pulses and a receive amplification with a 71-dB dynamic range, including 12 dB of programmable gain over a 3-dB bandwidth of 21 MHz. The functionality of the ASIC has been successfully demonstrated in a 3-D imaging experiment.

27. Exploiting nonlinear wave propagation to improve the precision of ultrasonic flow meters
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; N. de Jong; M. A. P. Pertijs; M. D. Verweij;
    Ultrasonics,
    Volume 116, pp. 106476, September 2021. DOI: 10.1016/j.ultras.2021.106476

28. A Pitch-Matched Analog Front-End with Continuous Time-Gain Compensation for High-Density Ultrasound Transducer Arrays
    P. Guo; Z. Y. Chang; E. Noothout; H. J. Vos; J. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
    In Proc. European Solid-State Circuits Conference (ESSCIRC),
    pp. 163-166, September 2021.
    
    Abstract: ...

    This paper presents a compact programmable high-voltage (HV) pulser for ultrasound imaging, designed for driving capacitive micro-machined ultrasonic transducers (CMUTs) in miniature ultrasound probes. To enable bipolar return-to-zero pulsing and embedded transmit/receive switching, a compact back-to-back isolating HV switch is proposed that employs HV floating-gate drivers with only one HV MOS transistor each. The pulser can be digitally programmed to generate bipolar pulses with and without return-to-zero, with a peak-to-peak swing up to 60 V, as well as negative and positive unipolar pulses. It can generate bursts of up to 63 pulses, with a maximum pulse frequency of 9 MHz for an 18 pF transducer capacitance. Realized in TSMC 0.18 μm HV BCD technology, the pulser occupies only 0.167 mm2. Electrical characterization results of the pulser, as well as acoustic results obtained in combination with a 7.5-MHz CMUT transducer, are presented.

29. Experimental Investigation of the Effect of Subdicing on an Ultrasound Matrix Transducer
    D. Simoes dos Santos; F. Fool; T. Kim; E. Noothout; H. J. Vos; J. G. Bosch; M. A. P. Pertijs; M. D. Verweij; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2021. DOI: 10.1109/ius52206.2021.9593315
    
    Abstract: ...

    Over the past decades, real-time three-dimensional (3D) medical ultrasound has attracted much attention since it enables clinicians to diagnose more accurately. This calls for ultrasound matrix transducers with a large number of elements, which can be interfaced with an application-specific integrated circuit (ASIC) for data reduction. An important aspect of the design of such a transducer is the geometry of each element, since it affects the mode of vibration and, consequently, the efficiency of the transducer. In this paper, we experimentally investigate the effect of subdicing on a piezoelectric (PZT) transducer. We fabricate and acoustically characterize a prototype PZT matrix transducer built on top of ASICs. The prototype transducer contains subdiced and non-subdiced elements, whose performance can be directly compared under the same conditions. Measurement results show that subdiced elements have a better performance compared to non-subdiced ones. Subdicing increases the peak pressure by 25%, raises the bandwidth by 10% and reduces the ringing time by 25%.

30. Automatic beam alignment in a clamp-on ultrasonic flow meter based on array transducers
    J. Massaad; P. van Neer; D. van Willigen; N. de Jong; M. Pertijs; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2021. abstract.

31. Feasibility of measuring flow velocity profiles with array-based clamp-on ultrasonic flow meters
    D. van Willigen; P. van Neer; J. Massaad; N. de Jong; M. Verweij; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2021. abstract.

32. A Compact Integrated High -Voltage Pulserfor 3D Miniature Ultrasound Probes
    Yannick Hopf; Mehdi Soozande; Boudewine Ossenkoppele; Hendrik J. Vos; Martin D. Verweij; Johan G. Bosch; Nico de Jong; Michiel A. P. Pertijs;
    In Annual Workshop on Circuits, Systems and Signal Processing (ProRISC),
    July 2021. poster.

33. An Area-Efficient Continuous Time-Gain Compensation Amplifier for Ultrasound Application
    P. Guo; Z.Y. Chang; E. Noothout; H.J. Vos; J.G. Bosch; N. de Jong; M.D. Verweij; M.A.P. Pertijs;
    In Annual Workshop on Circuits, Systems and Signal Processing (ProRISC),
    July 2021. poster.

34. Impact of Bit Errors in Digitized RF Data on Ultrasound Image Quality
    Z. Chen; M. Soozande; H. Vos; J. Bosch; M. Verweij; N. de Jong; M. Pertijs;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 67, Issue 1, pp. 13-24, January 2020. DOI: 10.1109/TUFFC.2019.2937462
    
    Abstract: ...

    This paper quantitatively analyzes the impact of bit errors in digitized RF data on ultrasound image quality. The quality of B-mode images in both linear and phased array imaging is evaluated by means of three objective image quality metrics: peak signal-to-noise ratio, structural similarity index and contrast-to-noise ratio, when bit errors are introduced to the RF data with different bit-error rates (BERs). The effectiveness of coding schemes for forward error detection and correction to improve the image quality is also studied. The results show that ultrasound imaging is inherently resilient to high BER. The image quality suffers unnoticeable degradation for BER lower than 1E-6. Simple 1-bit parity coding with 9% added redundancy helps to retain similar image quality for BER up to 1E-4, and Hamming coding with 33.3% added redundancy allows the BER to increase to 1E-3. These results can serve as a guideline in the datalink design for ultrasound probes with in-probe receive digitization. With much more relaxed BER requirements than in typical datalinks, the design can be optimized by allowing fewer cables with higher data rate per cable or lower power consumption with the same cable count.

35. An Algorithm to Minimize the Zero-Flow Error in Transit-Time Ultrasonic Flow Meters
    Douwe M. van Willigen; Paul L.M.J. van Neer; Jack Massaad; Nico de Jong; Martin D. Verweij; Michiel A.P. Pertijs;
    IEEE Transactions on Instrumentation and Measurement,
    2020. DOI: 10.1109/TIM.2020.3007907
    
    Abstract: ...

    Transit-time ultrasonic flow meters are widely used in industry to measure fluid flow. In practice ultrasonic flow meters either show a zero-flow error or suffer from a significant random error due to a limited signal-to-noise ratio, requiring a significant amount of averaging to achieve good precision. This work presents a method that minimizes the zero-flow error whilst keeping the random error low, independent of the hardware used. The proposed algorithm can adjust to changing zero-flow errors while a flow is present. The technique combines the benefits of two common methods of determining the transit-time difference between the upstream and downstream ultrasonic waves: cross-correlation and zero-crossing detection. The algorithm is verified experimentally using a flow-loop. It is shown that the zero-flow error can be greatly reduced without compromising the random error or increasing circuit complexity.

36. Suppression of Lamb wave excitation via aperture control of a transducer array for ultrasonic clamp-on flow metering
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; M. A. P. Pertijs; N. de Jong; M. D. Verweij;
    Journal of the Acoustical Society of America,
    Volume 147, Issue 4, pp. 2670-2681, February 2020. DOI: 10.1121/10.0001135
    
    Abstract: ...

    During ultrasonic clamp-on flow metering, Lamb waves propagating in the pipe wall may limit the measurement accuracy by introducing absolute errors in the flow estimates. Upon reception, these waves can interfere with the up and downstream waves refracting from the liquid, and disturb the measurement of the transit time difference that is used to obtain the flow speed. Thus, suppression of the generation of Lamb waves might directly increase the accuracy of a clamp-on flow meter. Existing techniques apply to flow meters with single element transducers. This paper considers the application of transducer arrays and presents a method to achieve a predefined amount of suppression of these spurious Lamb waves based on appropriate amplitude weightings of the transducer elements. Finite element simulations of an ultrasonic clamp-on flow measurement setting will be presented to show the effect of array aperture control on the suppression of the Lamb waves in a 1-mm-thick stainless steel pipe wall. Furthermore, a proof-of-principle experiment will be shown that demonstrates a good agreement with the simulations.

37. Towards a calibration-free ultrasonic clamp-on flow meter: Pipe geometry measurements using matrix arrays
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; M. A. P. Pertijs; N. de Jong; M. D. Verweij;
    Proceedings of Meetings on Acoustics,
    Volume 39, Issue 1, February 2020. DOI: 10.1121/2.0001187
    
    Abstract: ...

    Current ultrasonic clamp-on flow meters are manually calibrated. This process is based on manual placement of two single-element transducers along a pipe wall. Due to the usually unknown pipe properties and inhomogeneities in the pipe geometry, the axial distance of the transducers needs to be manually calibrated to align the location of the emitted beam on the receiver. In this work it is presented an automatic calibration procedure, based on matrix transducer arrays, to provide calibration information that would normally be entered into the instrument manually prior to ultrasonic clamp-on flow measurements. The calibration consists of two steps: First, along the axial direction of the pipe, Lamb waves are excited and recorded. Then, the measured time signals are combined with the Rayleigh-Lamb dispersion equation to extract pipe wall thickness and bulk wave sound speeds. Second, along the circumferential direction of the pipe, a specific Lamb wave mode is excited and recorded, from which the pipe diameter is estimated. The potential of both calibration procedures is shown, and the necessity of a matrix transducer array (i.e. small elements) is highlighted.

38. An Algorithm to Minimize the Zero-Flow Error in Transit-Time Ultrasonic Flow Meters
    D. M. van Willigen; P. L. M. J. van Neer; J. Massaad; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
    IEEE Transactions on Instrumentation and Measurement,
    Volume 70, pp. 1-9, July 2020. DOI: 10.1109/TIM.2020.3007907
    
    Abstract: ...

    Transit-time ultrasonic flowmeters are widely used in industry to measure fluid flow. In practice, ultrasonic flowmeters either show a zero-flow error or suffer from a significant random error due to a limited signal-to-noise ratio, requiring a significant amount of averaging to achieve good precision. This work presents a method that minimizes the zero-flow error while keeping the random error low, independent of the hardware used. The proposed algorithm can adjust to changing zero-flow errors, while a flow is present. The technique combines the benefits of two common methods of determining the transit time difference between the upstream and downstream ultrasonic waves: cross correlation and zero-crossing detection. The algorithm is verified experimentally using a flow loop. It is shown that the zero-flow error can be greatly reduced without compromising the random error or increasing circuit complexity.

39. Receive/Transmit Aperture Selection for 3D Ultrasound Imaging with a 2D Matrix Transducer
    M. Mozaffarzadeh; M. Soozande; F. Fool; M. A. P. Pertijs; H. J. Vos; M. D. Verweij; J. G. Bosch; N. de Jong;
    MDPI Applied Sciences,
    Volume 10, Issue 15, July 2020. DOI: 10.3390/app10155300
    
    Abstract: ...

    Recently, we realized a prototype matrix transducer consisting of 48 rows of 80 elements on top of a tiled set of Application Specific Integrated Circuits (ASICs) implementing a row-level control connecting one transmit/receive channel to an arbitrary subset of elements per row. A fully sampled array data acquisition is implemented by a column-by-column (CBC) imaging scheme (80 transmit-receive shots) which achieves 250 volumes/second (V/s) at a pulse repetition frequency of 20 kHz. However, for several clinical applications such as carotid pulse wave imaging (CPWI), a volume rate of 1000 per second is needed. This allows only 20 transmit-receive shots per 3D image. In this study, we propose a shifting aperture scheme and investigate the effects of receive/transmit aperture size and aperture shifting step in the elevation direction. The row-level circuit is used to interconnect elements of a receive aperture in the elevation (row) direction. An angular weighting method is used to suppress the grating lobes caused by the enlargement of the effective elevation pitch of the array, as a result of element interconnection in the elevation direction. The effective aperture size, level of grating lobes, and resolution/sidelobes are used to select suitable reception/transmission parameters. Based on our assessment, the proposed imaging sequence is a full transmission (all 80 elements excited at the same time), a receive aperture size of 5 and an aperture shifting step of 3. Numerical results obtained at depths of 10, 15, and 20 mm show that, compared to the fully sampled array, the 1000 V/s is achieved at the expense of, on average, about two times wider point spread function and 4 dB higher clutter level. The resulting grating lobes were at −27 dB. The proposed imaging sequence can be used for carotid pulse wave imaging to generate an informative 3D arterial stiffness map, for cardiovascular disease assessment.

40. Experimental Characterization of a Linear Transducer Array Prototype for Ultrasonic Clamp-on Flow Metering
    J. Massaad; D. van Willigen; P. van Neer; E. Noothout; N. de Jong; M. Pertijs; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2020. abstract.

41. A 12×80 Element Ultrasound Transceiver ASIC With Enhanced Charge Injection Performance for 3-D Carotid Artery Imaging
    T. Kim; F. Fool; E. Kang; Z. Y. Chang; E. Noothout; J. G. Bosch; M. D. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2020. abstract.

42. 3D High Frame Rate Imaging Scheme for Ultrasound Carotid Imaging
    M. Soozande; M. Mozzaffarzadeh; F. Fool; T. Kim; E. Kang; M. Pertijs; M. Verweij; H. J. Vos; J. G. Bosch; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2020. abstract.

43. Feasibility of High Frame Rate 3-D Intracardiac Echography using Fan-Beam Transmissions
    M. Soozande; B. Ossenkoppele; Y. Hopf; M. A. P. Pertijs; M. D. Verweij; H. J. Vos; J. G. Bosch; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2019.

44. Fabrication and characterization of a prototype forward-looking single-cable 64-element intra-vascular ultrasound probe
    D. van Willigen; M. Mozaffarzadeh; E. Noothout; M. Verweij; N. de Jong; M. Pertijs; V. Daeichin;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2019.

45. 3D high frame rate flow measurement using a prototype matrix transducer for carotid imaging
    F. Fool; H. J. Vos; M. Shabanimotlagh; T. Kim; E. Kang; M. Pertijs; N. de Jong; M. D. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2019.

46. A 1.54mW/Element 150μm-Pitch-Matched Receiver ASIC with Element-Level SAR/Shared-Single-Slope Hybrid ADCs for Miniature 3D Ultrasound Probes
    J. Li; Z. Chen; M. Tan; D. van Willigen; C. Chen; Z. Y. Chang; E. Noothout; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
    In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
    IEEE, pp. 1-2, June 2019.

47. Acoustic Stack Design of a Transducer Array for Ultrasonic Clamp-on Flow Metering
    J. Massaad; D. van Willigen; P. van Neer; N. de Jong; M. Pertijs; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2019.

48. Pipe geometry calibration measurements for the improvement of ultrasonic clamp-on flow meters
    J. Massaad; D. van Willigen; P. van Neer; N. de Jong; M. Pertijs; M. Verweij;
    In Meeting of the Acoustical Society of America,
    November 2019. (abstract),. DOI: 10.1121/1.5136993

49. Lithographic apparatus and device manufacturing method involving a heater
    T.P.M. Cadee; JHW Jacobs; N ten Kate; E.R. Loopstra; A.L.H.J. van Meer; J.J.S.M. Mertens; C.G.M. de Mol; M.J.E.H. Muitjens; A.J. van der Net; J.J. Ottens; J.A. Quaedackers; M.E. Reuhman-huisken; M.K. Stavenga; Marco ;
    Patent, United States US20190235397A1, August 2019.
    
    Abstract: ...

    A lithographic apparatus is described having a liquid supply system configured to at least partly fill a space between a projection system of the lithographic apparatus and a substrate with liquid, a barrier member arranged to substantially contain the liquid within the space, and a heater.
    
    document

50. Multiline 3D beamforming using micro-beamformed datasets for pediatric transesophageal echocardiography
    D. Bera; S. B. Raghunathan; C. Chen; Z. Chen; M. A. P. Pertijs; M. D. Verweij; V. Daeichin; H. J. Vos; A. F. W. van der Steen; N. de Jong; J. G. Bosch;
    Physics in Medicine \& Biology,
    Volume 63, Issue 7, pp. 1-16, March 2018. DOI: 10.1088/1361-6560/aab45e
    
    Abstract: ...

    Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issues, we have recently developed a prototype miniaturized matrix transducer for pediatric patients with micro-beamforming and a small central transmitter. In this paper we propose two multiline parallel 3D beamforming techniques (µBF25 and µBF169) using the micro-beamformed datasets from 25 and 169 transmit events to achieve volume rates of 300 Hz and 44 Hz, respectively. Both the realizations use angle-weighted combination of the neighboring overlapping sub-volumes to avoid artifacts due to sharp intensity changes introduced by parallel beamforming. In simulation, the image quality in terms of the width of the point spread function (PSF), lateral shift invariance and mean clutter level for volumes produced by µBF25 and µBF169 are similar to the idealized beamforming using a conventional single-line acquisition with a fully-sampled matrix transducer (FS4k, 4225 transmit events). For completeness, we also investigated a 9 transmit-scheme (3  ×  3) that allows even higher frame rates but found worse B-mode image quality with our probe. The simulations were experimentally verified by acquiring the µBF datasets from the prototype using a Verasonics V1 research ultrasound system. For both µBF169 and µBF25, the experimental PSFs were similar to the simulated PSFs, but in the experimental PSFs, the clutter level was ~10 dB higher. Results indicate that the proposed multiline 3D beamforming techniques with the prototype matrix transducer are promising candidates for real-time pediatric 3D TEE.

51. A Reconfigurable Ultrasound Transceiver ASIC With 24 × 40 Elements for 3D Carotid Artery Imaging
    E. Kang; Q. Ding; M. Shabanimotlagh; P. Kruizinga; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 53, Issue 7, pp. 2065-2075, July 2018. DOI: 10.1109/JSSC.2018.2820156
    
    Abstract: ...

    This paper presents an ultrasound transceiver application-specific integrated circuit (ASIC) designed for 3-D ultrasonic imaging of the carotid artery. This application calls for an array of thousands of ultrasonic transducer elements, far exceeding the number of channels of conventional imaging systems. The 3.6 x 6.8 mm² ASIC interfaces a piezo-electric transducer (PZT) array of 24 x 40 elements, directly integrated on top of the ASIC, to an imaging system using only 24 transmit and receive channels. Multiple ASICs can be tiled together to form an even bigger array. The ASIC, implemented in a 0.18 μm high-voltage (HV) BCD process, consists of a reconfigurable switch matrix and row-level receive circuits. Each element is associated with a compact bootstrapped HV transmit switch, an isolation switch for the receive circuits and programmable logic that enables a variety of imaging modes. Electrical and acoustic experiments successfully demonstrate the functionality of the ASIC. In addition, the ASIC has been successfully used in a 3-D imaging experiment.

52. Fast volumetric imaging using a matrix TEE probe with partitioned transmit-receive array
    D. Bera; F. van den Adel; N. Radeljic-Jakic; B. Lippe; M. Soozande; M. A. P. Pertijs; M. D. Verweij; P. Kruizinga; V. Daeichin; H. J. Vos; A. F. W. van der Steen; J. G. Bosch; N. de Jong;
    Ultrasound in Medicine \& Biology,
    Volume 44, Issue 9, pp. 2025-2042, July 2018. DOI: 10.1016/j.ultrasmedbio.2018.05.017
    
    Abstract: ...

    We describe a 3-D multiline parallel beamforming scheme for real-time volumetric ultrasound imaging using a prototype matrix transesophageal echocardiography probe with diagonally diced elements and separated transmit and receive arrays. The elements in the smaller rectangular transmit array are directly wired to the ultrasound system. The elements of the larger square receive aperture are grouped in 4 × 4-element sub-arrays by micro-beamforming in an application-specific integrated circuit. We propose a beamforming sequence with 85 transmit–receive events that exhibits good performance for a volume sector of 60° × 60°. The beamforming is validated using Field II simulations, phantom measurements and in vivo imaging. The proposed parallel beamforming achieves volume rates up to 59 Hz and produces good-quality images by angle-weighted combination of overlapping sub-volumes. Point spread function, contrast ratio and contrast-to-noise ratio in the phantom experiment closely match those of the simulation. In vivo 3-D imaging at 22-Hz volume rate in a healthy adult pig clearly visualized the cardiac structures, including valve motion.

53. A Front-End ASIC with High-Voltage Transmit Switching and Receive Digitization for 3D Forward-Looking Intravascular Ultrasound Imaging
    M. Tan; C. Chen; Z. Chen; J. Janjic; V. Daeichin; Z. Y. Chang; E. Noothout; G. van Soest; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 53, Issue 8, pp. 2284-2297, August 2018. DOI: 10.1109/JSSC.2018.2828826
    
    Abstract: ...

    This paper presents an area- and power-efficient application-specified integrated circuit (ASIC) for 3-D forward-looking intravascular ultrasound imaging. The ASIC is intended to be mounted at the tip of a catheter, and has a circular active area with a diameter of 1.5 mm on the top of which a 2-D array of piezoelectric transducer elements is integrated. It requires only four micro-coaxial cables to interface 64 receive (RX) elements and 16 transmit (TX) elements with an imaging system. To do so, it routes high-voltage (HV) pulses generated by the system to selected TX elements using compact HV switch circuits, digitizes the resulting echo signal received by a selected RX element locally, and employs an energy-efficient load-modulation datalink to return the digitized echo signal to the system in a robust manner. A multi-functional command line provides the required sampling clock, configuration data, and supply voltage for the HV switches. The ASIC has been realized in a 0.18-μm HV CMOS technology and consumes only 9.1 mW. Electrical measurements show 28-V HV switching and RX digitization with a 16-MHz bandwidth and 53-dB dynamic range. Acoustical measurements demonstrate successful pulse transmission and reception. Finally, a 3-D ultrasound image of a three-needle phantom is generated to demonstrate the imaging capability.

54. Acoustic characterization of a miniature matrix transducer for pediatric 3D transesophageal echocardiography
    V. Daeichin; D. Bera; S. Raghunathan; M. ShabaniMotlagh; Z. Chen; C. Chen; E. Noothout; H. J. Vos; M. Pertijs; J. Bosch; N. de Jong; M. Verweij;
    Ultrasound in Medicine \& Biology,
    Volume 44, Issue 10, pp. 2143-2154, October 2018. DOI: 10.1016/j.ultrasmedbio.2018.06.009
    
    Abstract: ...

    This paper presents the design, fabrication and characterization of a miniature PZT-on-CMOS matrix transducer for real-time pediatric 3-dimensional (3D) transesophageal echocardiography (TEE). This 3D TEE probe consists of a 32 × 32 array of PZT elements integrated on top of an Application Specific Integrated Circuit (ASIC). We propose a partitioned transmit/receive array architecture wherein the 8 × 8 transmitter elements, located at the centre of the array, are directly wired out and the remaining receive elements are grouped into 96 sub-arrays of 3 × 3 elements. The echoes received by these sub-groups are locally processed by micro-beamformer circuits in the ASIC that allow pre-steering up to ±37°. The PZT-on-CMOS matrix transducer has been characterized acoustically and has a centre frequency of 5.8 MHz, -6 dB bandwidth of 67%, a transmit efficiency of 6 kPa/V at 30 mm, and a receive dynamic range of 85 dB with minimum and maximum detectable pressures of 5 Pa and 84 kPa respectively. The properties are very suitable for a miniature pediatric real-time 3D TEE probe.

55. A Pitch-Matched Front-End ASIC with Integrated Subarray Beamforming ADC for Miniature 3-D Ultrasound Probes
    C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; M. Tan; H. Vos; J. Bosch; M. Verweij; N. de Jong; M. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 53, Issue 11, pp. 3050-3064, November 2018. DOI: 10.1109/JSSC.2018.2864295
    
    Abstract: ...

    This paper presents a front-end application-specified integrated circuit (ASIC) integrated with a 2-D PZT matrix transducer that enables in-probe digitization with acceptable power dissipation for the next-generation endoscopic and catheter-based 3-D ultrasound imaging systems. To achieve power-efficient massively parallel analog-to-digital conversion (ADC) in a 2-D array, a 10-bit 30 MS/s beamforming ADC that merges the subarray beamforming and digitization functions in the charge domain is proposed. It eliminates the need for costly intermediate buffers, thus significantly reducing both power consumption and silicon area. Self-calibrated charge references are implemented in each subarray to further optimize the system-level power efficiency. High-speed datalinks are employed in combination with the subarray beamforming scheme to realize a 36-fold channel-count reduction and an aggregate output data rate of 6 Gb/s for a prototype receive array of 24 x 6 elements. The ASIC achieves a record power efficiency of 0.91 mW/element during receive. Its functionality has been demonstrated in both electrical and acoustic imaging experiments.

56. A 2D Ultrasound Transducer with Front-End ASIC and Low Cable Count for 3D Forward-Looking Intravascular Imaging: Performance and Characterization
    J. Janjic; M. Tan; E. Noothout; C. Chen; Z. Chan; Z. Y. Chang; R. H. S. H. Beurskens; G. van Soest; A. F. W. van der Steen; M. D. Verweij; M. A. P. Pertijs; N. de Jong;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 65, Issue 10, pp. 1832--1844, October 2018. Featured Cover Article. DOI: 10.1109/TUFFC.2018.2859824
    
    Abstract: ...

    Intravascular ultrasound is an imaging modality used to visualize atherosclerosis from within the inner lumen of human arteries. Complex lesions like chronic total occlusions require forward-looking intravascular ultrasound (FL-IVUS), instead of the conventional side-looking geometry. Volumetric imaging can be achieved with 2D array transducers, which present major challenges in reducing cable count and device integration. In this work we present an 80-element lead zirconium titanate (PZT) matrix ultrasound transducer for FL-IVUS imaging with a front-end application-specific integrated circuit (ASIC) requiring only 4 cables. After investigating optimal transducer designs we fabricated the matrix transducer consisting of 16 transmit (TX) and 64 receive (RX) elements arranged on top of an ASIC having an outer diameter of 1.5 mm and a central hole of 0.5 mm for a guidewire. We modeled the transducer using finite element analysis and compared the simulation results to the values obtained through acoustic measurements. The TX elements showed uniform behavior with a center frequency of 14 MHz, a -3 dB bandwidth of 44 % and a transmit sensitivity of 0.4 kPa/V at 6 mm. The RX elements showed center frequency and bandwidth similar to the TX elements, with an estimated receive sensitivity of 3.7 μV/Pa. We successfully acquired a 3D FL image of three spherical reflectors in water using delay-and-sum beamforming and the coherence factor method. Full synthetic aperture acquisition can be achieved with frame rates on the order of 100 Hz. The acoustic characterization and the initial imaging results show the potential of the proposed transducer to achieve 3D FL-IVUS imaging.

57. A 0.91mW/Element Pitch-Matched Front-End ASIC with Integrated Subarray Beamforming ADC for Miniature 3D Ultrasound Probes
    C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; M. Tan; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    In Dig. Techn. Papers IEEE International Solid-State Circuits Conference (ISSCC),
    pp. 186-187, February 2018. DOI: 10.1109/ISSCC.2018.8310246

58. Clamp-on Ultrasonic Flow-metering via Matrix Transducers
    J. Massaad; P. van Neer; D. van Willigen; N. de Jong; M. Pertijs; Martin Verweij;
    In Proc. Int. Conf. on Ultrasonic-based Applications,
    June 2018.

59. Monitoring infant brain perfusion by trans-fontanel echography
    A. J. Kortenbout; H. J. Vos; J. Dudink; M. D. Verweij; M. A. P. Pertijs; J. G. Bosch; N. de Jong;
    In Proc. PhD Training Course Dutch Heart Foundation,
    October 2018.

60. ASIC design for a single-cable 64-element ultrasound probe
    D. van Willigen; J. Janjic; E. Kang; Z. Y. Chang; E. Noothout; M. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2018.
    
    Abstract: ...

    This paper presents an ASIC (Application Specific Integrated Circuit) design for a catheter probe that interfaces 64 piezoelectric elements directly integrated on top of the ASIC to an imaging system using a single micro-coaxial cable. Each of the piezo elements can be used for both transmit (TX) and receive (RX), enabling full synthetic aperture imaging. A prototype has been realized with a 1.5mm diameter circular layout, intended for 3D intra-vascular ultrasound imaging. The functionality of this ASIC has been successfully demonstrated in a 3D imaging experiment. The design allows a single-element transducer to be replaced by a transdcuer array while using the same cable, making it a promising solution for 3D imaging with size constrained probes.

61. A Power-Efficient Transmit Beamformer ASIC for 3-D Catheter-Based/ Endoscopic Probes
    Z. Chen; E. Kang; Z. Y. Chang; E. Noothout; J. G. Bosch; M. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, October 2018. (abstract).
    
    Abstract: ...

    To reduce cable count in 3D catheter-based or endoscopic probes, generation of the (HV) transmit (TX) signals using an in-probe ASIC is a promising solution. However, such ASICs are subject to stringent power-consumption constraints to limit self-heating. The power consumed by conventional HV pulsers is at least fCV^2, due to the periodic charging/discharging of the transducer element capacitance C. HV switches can be used to connect elements to a pulser in the imaging system, thus only dissipating a fraction of fCV^2 in the probe, but full TX beamforming (BF) cannot be realized using switches. In this work, we propose a power-efficient HV TX circuit capable of providing full TX BF using only 3 HV connections to the system. Implemented in a 0.18um BCD process, the ASIC was fully evaluated by means of post-layout simulations.

62. Feasibility of ultrasound flow measurements via non-linear wave propagation
    J. Massaad; P. L. M. J. van Neer; D. M. van Willigen; N. de Jong; M. A. P. Pertijs; M. D. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2018. DOI: 10.1109/ULTSYM.2018.8579943
    
    Abstract: ...

    Typically, ultrasonic flow meters assume linear wave propagation. Nevertheless, if the transducers of an ultrasonic flow sensor excite a pressure wave with a high amplitude, nonlinear wave propagation effects become significant. The appearance of higher harmonics increases the bandwidth of the received signal, which may potentially lead to a more precise flow measurement. However, the question arises whether the increased bandwidth can be used in practice, since the intensity of the 2nd harmonic can be 25 dB below the fundamental. One exploit of the increased bandwidth is to filter the received signals and to obtain two components: the fundamental and the 2nd harmonic. Differences between the upstream and downstream transit times are directly related to the flow speed, and these can be computed for each component of the received signals. This paper shows that averaging the transit time differences of the fundamental signals and the 2nd harmonic signals results in a lower standard deviation compared to the standard deviation of the transit time differences of the fundamental or the 2nd harmonic signal alone. This demonstrates the feasibility of using non-linear wave propagation to improve the precision of flow measurements using ultrasound.

63. Minimizing the zero-flow error in transit time ultrasonic flow meters
    D. van Willigen; P. van Neer; J. Massaad; N. de Jong; M. Verweij; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2018. DOI: 10.1109/ULTSYM.2018.8579771
    
    Abstract: ...

    Transit-time ultrasonic flow meters are based on the fundamental idea that the flow is the only non-reciprocal effect between an upstream and downstream measurement. Non-identical transducers can be used in a reciprocal manner if the circuit is made reciprocal. In this paper we analyze the effect of driver- and readout electronics on the zero-flow error in transit-time ultrasonic flow meters by simulation and measurement. Using the frequency characteristic of two nonidentical transducers, the cause of the zero-flow error in nonreciprocal circuits is evaluated. Both simulation and measurement results show that the lowest zero-flow error can be obtained by using circuits that have an impedance significantly higher or lower than the impedance of the transducers.

64. A quantitative study on the impact of bit errors on image quality in ultrasound probes with in-probe digitization
    Z. Chen; M. Soozande; H. J. Vos; J. G. Bosch; M. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, October 2018. (abstract).
    
    Abstract: ...

    Integrating ultrasound transducers with ASICs which digitize and multiplex the received echo signals effectively mitigates the burden of signal transmission for 3-D catheter-based or endoscopic probes. Multiplexing the echo signals from multiple elements onto a cable reduces the cable count, but requires a higher data rate per cable, which typically involves a trade-off between power consumption and bit-error rate (BER). Understanding the impact of finite BER on the resulting image quality is a necessity to optimize the cable count and power consumption. In this work, this impact is quantitatively assessed using Matlab simulations. The effectiveness of error correction is also investigated.

65. Virtually Extended Array imaging improves lateral resolution in high frame rate volumetric imaging
    M. Soozande; F. Fool; M. Shabanimotlagh; M. Pertijs; M. Verweij; H. J. Vos; J. G. Bosch; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, October 2018. DOI: 10.1109/ULTSYM.2018.8580018
    
    Abstract: ...

    Matrix arrays for endoscopic and catheter-based applications are restricted to small physical apertures, which limits their lateral resolution. In addition, when aiming for high volume rate imaging and utilizing the recent methods of transmitting a single or few diverging waves (DW), lateral resolution further deteriorates. In this work, we propose a high frame rate transmission scheme which outperforms alternative methods in lateral resolution. To improve the lateral resolution and side-lobe level, we propose to transmit only on a sub-aperture on either side of the array and apply a specific weighting function to received data. Compared to single-DW imaging, the proposed Sub-aperture Virtually Extended Array reduces the PSF width and sidelobe level by 16% and 5dB respectively and provides a similar SNR at the cost of halving the frame rate.

66. A Front-end ASIC with Receive Sub-Array Beamforming Integrated with a 32 × 32 PZT Matrix Transducer for 3-D Transesophageal Echocardiography
    C. Chen; Z. Chen; D. Bera; S. B. Raghunathan; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; J. Ponte; C. Prins; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    IEEE Journal of Solid-State Circuits,
    Volume 52, Issue 4, pp. 994‒1006, April 2017. DOI: 10.1109/JSSC.2016.2638433
    
    Abstract: ...

    This paper presents a power- and area-efficient front-end application-specific integrated circuit (ASIC) that is directly integrated with an array of 32 × 32 piezoelectric transducer elements to enable next-generation miniature ultrasound probes for real-time 3-D transesophageal echocardiography. The 6.1 × 6.1 mm2 ASIC, implemented in a low-voltage 0.18-μm CMOS process, effectively reduces the number of receive (RX) cables required in the probe's narrow shaft by ninefold with the aid of 96 delay-and-sum beamformers, each of which locally combines the signals received by a sub-array of 3 × 3 elements. These beamformers are based on pipeline-operated analog sample-and-hold stages and employ a mismatch-scrambling technique to prevent the ripple signal associated with the mismatch between these stages from limiting the dynamic range. In addition, an ultralow-power low-noise amplifier architecture is proposed to increase the power efficiency of the RX circuitry. The ASIC has a compact element matched layout and consumes only 0.27 mW/channel while receiving, which is lower than the state-of-the-art circuit. Its functionality has been successfully demonstrated in 3-D imaging experiments.

67. Compressive 3D ultrasound imaging using a single sensor
    P. Kruizinga; P. van der Meulen; A. Fedjajevs; F. Mastik; G. Springeling; N. de Jong; J.G. Bosch; G. Leus;
    Science Advances,
    Volume 3, December 2017. ISSN: 2375-2548. DOI: 10.1126/sciadv.1701423
    document
    Youtube

68. Model-based image reconstruction for medical ultrasound
    P. Kruizinga; P. van der Meulen; F. Mastik; N. de Jong; J. G. Bosch; G. Leus;
    The Journal of the Acoustical Society of America,
    Volume 141, Issue 5, pp. 3610-3610, June 2017. DOI: 10.1121/1.4987733

69. Acoustic Characterization of a 32 × 32 Element PZT-on-ASIC Matrix Transducer for 3D Transesophageal Echocardiography
    M. Shabanimotlagh; S. Raghunathan; D. Bera; Z. Chen; C. Chen; V. Daeichin; M. Pertijs; J. G. Bosch; N. de Jong; M. Verweij;
    In Dutch Bio-Medical Engineering Conference,
    The Netherlands, 2017.

70. Acoustical compressive 3D imaging with a single sensor
    P. Kruizinga; P. van der Meulen; F. Mastik; A. Fedjajevs; G. Springeling; N. de Jong; G. Leus; J. G. Bosch;
    In 2017 IEEE International Ultrasonics Symposium (IUS),
    pp. 1-1, September 2017. DOI: 10.1109/ULTSYM.2017.8091779
    document

71. A Fresnel-inspired approach for steering and focusing a pulsed transmit beam with matrix array transducers
    M. Verweij; M. Pertijs; J. de Wit; F. Fool; H. Vos; N. de Jong;
    In The Journal of the Acoustical Society of America,
    June 2017. DOI: 10.1121/1.4987739
    
    Abstract: ...

    Matrix ultrasound transducers for medical diagnostic purposes are commercially available for a decade. A typical matrix transducer contains 1000 + elements, with a trend towards more and smaller elements. This number renders direct connection of each individual element to an ultrasound machine impractical. Consequently, it is cumbersome to employ traditional focusing and beamforming approaches that are based on transmit and receive signals having an individual time delay for each element. To reduce cable count during receive, one approach is to apply sub-arrays that locally combine the element signals using programmable delay-and-sum hardware, resulting in reduction by a factor 10. In transmit, achieving cable count reduction while keeping focusing and steering capabilities turns problematic once it becomes impossible to locally equip each element with its own high voltage pulser. To overcome this bottleneck for decreasing element size, here we present a Fresnel-inspired hardware and beam forming approach that is based on transmit pulses consisting of several periods of an oscillating waveform. These will be derived from one oscillating high voltage signal by using local switching and timing hardware. To demonstrate the feasibilities of our approach, we will show beam profiles and images for a miniature matrix transducer that we are currently developing.

72. A Front-End ASIC with High-Voltage Transmit Switching and Receive Digitization for Forward-Looking Intravascular Ultrasound
    M. Tan; C. Chen; Z. Chen; J. Janjic; V. Daeichin; Z. Y. Chang; E. Noothout; G. van Soest; M. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE Custom Integrated Circuits Conference (CICC),
    IEEE, pp. 1‒4, April 2017. DOI: 10.1109/cicc.2017.7993708

73. A Reconfigurable 24 × 40 Element Transceiver ASIC for Compact 3D Medical Ultrasound Probes
    E. Kang; Q. Ding; M. Shabanimotlagh; P. Kruizinga; Z. Y. Chang; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    In Proc. European Solid-State Circuits Conference (ESSCIRC),
    IEEE, pp. 211-214, September 2017.

74. A Front-End ASIC for Miniature 3-D Ultrasound Probes with In-Probe Receive Digitization
    C. Chen; Z. Chen; D. Bera; E. Noothout; Z. Y. Chang; H. Vos; J. Bosch; M. Verweij; N. de Jong; M. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, September 2017. Winner Best Student Paper Competition. DOI: 10.1109/ULTSYM.2017.8091913
    
    Abstract: ...

    This paper presents a front-end application-specific integrated circuit (ASIC) that demonstrates the feasibility of inprobe digitization for next-generation miniature 3-D ultrasound probes with acceptable power- and area-efficiency. The proposed design employs a low-power charge-domain ADC that is directly merged with the sample-and-hold delay lines in each subarray, and high-speed datalinks at the ASIC periphery to realize an additional channel-count reduction compared to prior work based on analog subarray beamforming. The 4.8 × 2 mm 2 ASIC, which has a compact layout element-matched to a 5-MHz 150-μm-pitch PZT matrix transducer, achieves an overall 36-fold channel-count reduction and a state-of-the-art power-efficiency with less than 1 mW/element power dissipation while receiving, which is acceptable even when scaled up to a 1000-element probe. The prototype ASIC has been fabricated in a 0.18 μm CMOS process. Its functionality has been successfully evaluated with both electrical and acoustical measurements.

75. Forward-Looking IVUS Transducer with Front-End ASIC for 3D Imaging
    J. Janjic; M. Tan; C. Chen; Z. Chen; E. Noothout; Z. Y. Chang; G. van Soest; M. Verweij; A. F. W. van der Steen; M. Pertijs; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-1, September 2017. (abstract).
    
    Abstract: ...

    Forward-looking intravascular ultrasound (FL-IVUS) transducers are needed to image complex lesions in the coronary arteries, such as chronic total occlusions (CTOs). To achieve 2D and 3D FL-IVUS imaging, transducer arrays can be integrated at the tip of the catheter. However, connecting the elements is challenging due to the limited space available. In this work, we present a FL-IVUS matrix transducer consisting of 16 transmit and 64 receive elements, which are interfaced with an ASIC that requires only 4 micro-coaxial cables. The transducer performance was characterized by hydrophone measurements and FL imaging of three spherical reflectors.

76. Volumetric imaging using adult matrix TEE with separated transmit and receive array
    D. Bera; F. van den Adel; N. Radeljic-Jakic; B. Lippe; M. Soozande; M. Pertijs; M. Verweij; P. Kruizinga; V. Daeichin; H. Vos; J. Bosch; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-1, September 2017. (abstract). DOI: 10.1109/ULTSYM.2017.8092906
    
    Abstract: ...

    The design of 3D TEE transducers poses severe technical challenges: channel count, electronics integration with high and low voltages, heat dissipation, etc. We present an adult matrix TEE probe with separate transmit (Tx) and receive (Rx) arrays allowing optimization in both Tx and Rx [1]. Tx elements are directly wired out, Rx employs integrated micro-beamformers in low-voltage (1.8/5.0V) chip technology. The prototype is fully integrated into a gastroscopic tube.

77. Towards 3D ultrasound imaging of the carotid artery using a programmable and tileable matrix array
    P. Kruizinga; E. Kang; M. Shabanimotlagh; Q. Ding; E. Noothout; Z. Y. Chang; H. J. Vos; J. G. Bosch; M. D. Verweij; M. A. P. Pertijs; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-3, September 2017. DOI: 10.1109/ULTSYM.2017.8091570
    
    Abstract: ...

    Accurate assessment of carotid artery disease by measuring blood flow, plaque deformation and pulse wave velocity using ultrasound imaging requires 3D information. Additionally, the volume rates should be high enough (> 1 kHz) to capture the full range of these fast transient phenomena. For this purpose, we have built a programmable, tileable matrix array that is capable of providing 3D ultrasound imaging at such volume rates. This array contains an application-specific integrated circuit (ASIC) right beneath the acoustic piezo-stack. The ASIC enables fast programmable switching between various configurations of elements connected to the acquisition system via a number of channels far smaller than the number of transducer elements. This design also allows for expanding the footprint by tiling several of these arrays together into one large array. We explain the working principles and show the first basic imaging results of a 2-by-1 tiled array.

78. Optimizing the directivity of piezoelectric matrix transducer elements mounted on an ASIC
    M. Shabanimotlagh; S. Raghunathan; V. Daeichin; P. Kruizinga; H. J. Vos; M. A. P. Pertijs; J. G. Bosch; N. de Jong; M. D. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1-4, September 2017. DOI: 10.1109/ULTSYM.2017.8091752
    
    Abstract: ...

    Over the last decade, clinical studies show a strong interest in real-time 3D imaging. This calls for ultrasound probes with high-element-count 2D matrix transducer arrays. These may be interfaced to an imaging system using an in-probe Application Specific Integrated Circuit (ASIC) that takes care of signal amplification, element switching, sub-array beamforming, etc. Since the ASIC is made from silicon and is mounted directly behind the transducer elements, it can acoustically be regarded as a rigid plate that can sustain traveling lateral waves. These waves lead to acoustical cross-talk between the elements, and results in extra peaks in the directivity pattern. We propose two solutions to this problem, based on numerical simulations. One approach is to decrease the phase velocity in the silicon by reducing the silicon thickness and absorbing the energy using a proper backing material. Another solution is to disturb the waves inside the silicon plate by sub-dicing the back-side of the ASIC. We conclude that both solutions can be used to improve the directivity pattern.

79. Probing the nuclear spin-lattice relaxation time at the nanoscale
    J.J.T. Wagenaar; A.M.J. Den Haan; J.M. De Voogd; T.A. De Jong; M. De Wit; K.M. Bastiaans; D.J. Thoen; A. Endo; T.M. Klapwijk; J. Zaanen; et al;
    arXiv preprint,
    2016. 10.1103/physrevapplied.6.014007.
    document

80. A Broadband Polyvinylidene Difluoride-Based Hydrophone with Integrated Readout Circuit for Intravascular Photoacoustic Imaging
    V. Daeichin; C. Chen; Q. Ding; M. Wu; R. Beurskens; G. Springeling; E. Noothout; M. D. Verweij; K. W. A. van Dongen; J. G. Bosch; A. F. W. van der Steen; N. de Jong; M. Pertijs; G. van Soest;
    Ultrasound in Medicine \& Biology,
    Volume 42, Issue 5, pp. 1239‒1243, May 2016. DOI: 10.1016/j.ultrasmedbio.2015.12.016
    
    Abstract: ...

    Intravascular photoacoustic (IVPA) imaging can visualize the coronary atherosclerotic plaque composition on the basis of the optical absorption contrast. Most of the photoacoustic (PA) energy of human coronary plaque lipids was found to lie in the frequency band between 2 and 15 MHz requiring a very broadband transducer, especially if a combination with intravascular ultrasound is desired. We have developed a broadband polyvinylidene difluoride (PVDF) transducer (0.6 × 0.6 mm, 52 μm thick) with integrated electronics to match the low capacitance of such a small polyvinylidene difluoride element (<5 pF/mm2) with the high capacitive load of the long cable (∼100 pF/m). The new readout circuit provides an output voltage with a sensitivity of about 3.8 μV/Pa at 2.25 MHz. Its response is flat within 10 dB in the range 2 to 15 MHz. The root mean square (rms) output noise level is 259 μV over the entire bandwidth (1–20 MHz), resulting in a minimum detectable pressure of 30 Pa at 2.25 MHz.

81. A Prototype PZT Matrix Transducer with Low-Power Integrated Receive ASIC for 3D Transesophageal Echocardiography.
    C. Chen; S. Raghunathan; Z. Yu; M. Shabanimotlag; Z. Chen; Z. Y. Chang; S. Blaak; C. Prins; J. Ponte; E. Noothout; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 63, Issue 1, pp. 47‒59, January 2016. DOI: 10.1109/tuffc.2015.2496580
    
    Abstract: ...

    This paper presents the design, fabrication, and experimental evaluation of a prototype lead zirconium titanate (PZT) matrix transducer with an integrated receive ASIC, as a proof of concept for a miniature three-dimensional (3-D) transesophageal echocardiography (TEE) probe. It consists of an array of 9 × 12 piezoelectric elements mounted on the ASIC via an integration scheme that involves direct electrical connections between a bond-pad array on the ASIC and the transducer elements. The ASIC addresses the critical challenge of reducing cable count, and includes front-end amplifiers with adjustable gains and microbeamformer circuits that locally process and combine echo signals received by the elements of each 3 × 3 subarray. Thus, an order-of-magnitude reduction in the number of receive channels is achieved. Dedicated circuit techniques are employed to meet the strict space and power constraints of TEE probes. The ASIC has been fabricated in a standard 0.18-μm CMOS process and consumes only 0.44 mW/channel. The prototype has been acoustically characterized in a water tank. The ASIC allows the array to be presteered across ±37° while achieving an overall dynamic range of 77 dB. Both the measured characteristics of the individual transducer elements and the performance of the ASIC are in good agreement with expectations, demonstrating the effectiveness of the proposed techniques.

82. Acoustic Characterisation of a 32 × 32 Element PZT-on-CMOS Matrix Transducer for 3D TEE
    S. Raghunathan; D. Bera; C. Chen; Z. Chen; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; H. Vos; C. Prins; J. Ponte; J. Bosch; M. Pertijs; N. de Jong; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    September 2016. (abstract).

83. A front-end ASIC with receive sub-array beamforming integrated with a 32 × 32 PZT matrix transducer for 3-D transesophageal echocardiography
    C. Chen; Z. Chen; D. Bera; S. B. Raghunathan; M. Shabanimotlagh; E. Noothout; Z. Y. Chang; J. Ponte; C. Prins; H. J. Vos; J. G. Bosch; M. D. Verweij; N. de Jong; M. A. P. Pertijs;
    In Dig. Techn. Paper IEEE Symposium on VLSI Circuits (VLSI),
    IEEE, pp. 1‒2, September 2016. DOI: 10.1109/vlsic.2016.7573470

84. A broadband PVDF-based hydrophone with integrated readout circuit for intravascular photoacoustic imaging
    V. Daeichin; C. Chen; Q. Ding; M. Wu; R. Beurskens; G. Springeling; E. Noothout; M. D. Verweij; K. W.A. van Dongen; J. G. Bosch; A. F. W. van der Steen; N. de Jong; M. Pertijs; G. van Soest;
    In Proc. SPIE Photonics West,
    SPIE, February 2016. DOI: 10.1016/j.ultrasmedbio.2015.12.016
    
    Abstract: ...

    Intravascular photoacoustic (IVPA) imaging can visualize the coronary atherosclerotic plaque composition on the basis of the optical absorption contrast. Most of the photoacoustic (PA) energy of human coronary plaque lipids was found to lie in the frequency band between 2 and 15 MHz requiring a very broadband transducer, especially if a combination with intravascular ultrasound is desired. We have developed a broadband polyvinylidene difluoride (PVDF) transducer (0.6 × 0.6 mm, 52 μm thick) with integrated electronics to match the low capacitance of such a small polyvinylidene difluoride element (<5 pF/mm2) with the high capacitive load of the long cable (∼100 pF/m). The new readout circuit provides an output voltage with a sensitivity of about 3.8 μV/Pa at 2.25 MHz. Its response is flat within 10 dB in the range 2 to 15 MHz. The root mean square (rms) output noise level is 259 μV over the entire bandwidth (1–20 MHz), resulting in a minimum detectable pressure of 30 Pa at 2.25 MHz.

85. The role of sub-dicing in the acoustical design of an ultrasound matrix transducer for carotid arteries imaging
    M. Shabanimotlagh; J. Janjic; S. Raghunathan; M. A. P. Pertijs; N. de Jong; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1‒4, September 2016. DOI: 10.1109/ultsym.2016.7728470
    
    Abstract: ...

    Accurate diagnostics of stenosis and blood flow distribution in carotid arteries requires transducers capable of producing 3D volume images with high frame rate for real time imaging. In the process of designing a matrix probe, an important goal is to realize the acoustic stack with high sensitivity and bandwidth. In this study, we employ a finite element analysis to evaluate the effect of sub-dicing on the performance of an acoustic stack in a piezoelectric matrix array. The array is integrated with an Application Specific Integrated Circuit (ASIC), which performs the task of signal amplification and efficient data reduction. The results show that two sub-dicing cuts can improve the sensitivity by 40%, bandwidth by 20%, and reduce the ringing time by 43%, which are all desired for improving the image quality.

86. Three-dimensional beamforming combining micro-beamformed RF datasets
    D. Bera; H. J. Vos; S. B. Raghunathan; C. Chen; Z. Chen; M. D. Verweij; M. A. P. Pertijs; N. de Jong; J. G. Bosch;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1‒4, September 2016. DOI: 10.1109/ultsym.2016.7728449
    
    Abstract: ...

    A general challenge in 3D volumetric imaging is the large channel count. One solution uses integrated microbeamformers. The reconstruction of the entire volume from these micro-beamformed datasets can be performed in many ways. In this paper we propose two 3D multiline beamforming techniques, suitable for producing volumes at high frame rate and compare the image qualities to a fully-sampled matrix. The performance of the proposed beamforming techniques was evaluated with simulations in FieldII. Results show that the proposed simple volume reconstruction technique (using 25 transmissions) produces volumes at very high frame rate, but with sharp intensity changes within the volume. The proposed advanced technique (using 169 transmissions) produces volumes very similar to a fully-sampled matrix transducer despite the micro-beamforming.

87. Nuclear magnetic resonance force microscopy at milliKelvin temperatures
    J. Wagenaar; A. den Haan; G. Koning; T. de Jong; L. Bossoni; Martin de Wit; D.J. Theon; A. Endo; T.M. Klapwijk; T. Oosterkamp;
    In Physics @ FOM Veldhoven,
    Veldhoven, the Netherlands, January 2015.

88. Acoustic Characterisation of a PZT Matrix With Integrated Electronics for a 3D-TEE Probe
    S. Raghunathan; C. Chen; M. Shabanimotlagh; Z. Chen; S. Blaak; Z. Yu; C. Prins; M. Pertijs; J. Bosch; N. de Jong; M. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    October 2015. (abstract).

89. Low Power Receive Electronics for a Miniature Real-Time 3D Ultrasound Probe
    Z. Chen; C. Chen; S. B. Raghunathan; D. Bera; Z. Chang; S. Blaak; C. Prins; J. Ponte; J. G. Bosch; N. de Jong; M. D. Verweij; M. A. P. Pertijs;
    In Proc. Conference for ICT-Research in the Netherlands (ICT.OPEN),
    The Netherlands, March 2015.

90. Low-power receive electronics for a miniature real-time 3D ultrasound probe
    M. Pertijs; C. Chen; S. Raghunathan; Z. Yu; M. ShabaniMotlagh; Z. Chen; Z. Y. Chang; E. Noothout; S. Blaak; J. Ponte; C. Prins; H. Bosch; M. Verweij; N. de Jong;
    In Proc. IEEE International Workshop on Advances in Sensors and Interfaces (IWASI),
    IEEE, pp. 235‒238, June 2015. invited paper. DOI: 10.1109/iwasi.2015.7184963

91. A single-cable PVDF transducer readout IC for intravascular photoacoustic imaging
    C. Chen; V. Daeichin; Q. Ding; G. van Soest; G. Springeling; T. van der Steen; M. Pertijs; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 1‒4, October 2015. DOI: 10.1109/ultsym.2015.0142
    
    Abstract: ...

    This paper presents a custom-designed single-cable readout IC for the reception of the broadband photoacoustic (PA) signal in intravascular photoacoustic (IVPA) imaging. The readout IC is intended for direct integration behind a broadband polyvinylidene fluoride (PVDF) transducer in an IVPA catheter tip to match the impedance between the small PVDF element and the connecting cable. The capability of the readout IC to work with a single cable that combines the output signal and the power supply ensures the mechanical flexibility of the IVPA catheter. Electrical measurements show that the readout IC provides a flat frequency response from 1 MHz to 20 MHz with a 6 mA external current supply. The acoustical measurements involving the readout IC and the PVDF transducer demonstrate a 60 dB dynamic range, a sensitivity of 3.8 μV/Pa at 2.25 MHz, and a broad receiving bandwidth from 2 MHz to 15 MHz.

92. Design of a Miniature Ultrasound Probe for 3D Transesophageal Echocardiography
    D. Bera; S. B. Raghunathan; C. Chen; S. Blaak; C. Prins; M. A. P. Pertijs; M. D. Verweij; J. G. Bosch; N. de Jong;
    In Annual Sensor Technology Workshop Sense of Contact,
    The Netherlands, April 2014.

93. Design of a miniature ultrasound probe for 3D transesophageal echocardiography
    S. B. Raghunathan; D. Bera; C. Chen; S. Blaak; C. Prins; M. A. P. Pertijs; J. G. Bosch; N. de Jong; M. D. Verweij;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 2091‒2094, September 2014. DOI: 10.1109/ultsym.2014.0521
    
    Abstract: ...

    The relatively large size of most of the current 3D Transesophageal Echocardiography probes (TEE) enables their usage in adults for short procedures only. In this paper, we propose a new miniature 3D TEE probe with a head volume of 1 cm3, that would be suitable for use in neonates or for prolonged transnasal use in adults. We focus on partitioned designs, in which a minority of transmit elements is directly wired out and the majority of receive elements connect to a limited number of receive cables via an ASIC that performs a nine-fold data reduction in receive mode. The designs are motivated based on the pressure and beam width of the transmitted field, and the resolution, grating lobes and side lobes in the received field.

94. Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography
    Z. Yu; S. Blaak; Z. Y. Chang; J. Yao; J. G. Bosch; C. Prins; C. T. Lancee; N. de Jong; M. A. P. Pertijs; G. C. M. Meijer;
    IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
    Volume 59, Issue 7, pp. 1500‒1512, July 2012. DOI: 10.1109/tuffc.2012.2350
    
    Abstract: ...

    There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-μm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.

95. A 9-channel low-power receiver ASIC for 3D transesophageal echocardiography
    Z. Yu; S. Blaak; C. Prins; Z. Y. Chang; C. T. Lancée; J. G. Bosch; N. de Jong; G. C. M. Meijer; M. A. P. Pertijs;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 2063‒2066, October 2012. DOI: 10.1109/ultsym.2012.0516
    
    Abstract: ...

    This paper presents a 9-channel low-power receiver ASIC dedicated to a matrix piezoelectric ultrasound transducer for 3D Trans-Esophageal Echocardiography (TEE). It consists of 9 low-noise amplifiers (LNAs), 9 time-gain-compensation (TGC) amplifiers and a 9:1 micro-beamformer. A prototype ASIC has been implemented in 0.35 μm CMOS technology, with a core area of 0.98 mm × 1.7 mm. It is operated at a 3.3 V supply and consumes only 0.5 mW per channel. The measured channel-to-channel mismatch is within ±1 dB. Acoustic measurements proved the micro-beamforming function of the ASIC when processing real ultrasound signals from a 3 × 3 transducer array. These promising results show that this design, after layout optimization, is suitable to be scaled up to accommodate a full matrix transducer.

96. Design of a Beamformer for an Ultrasonic Matrix Transducer for 3D Transesophageal Echocardiography
    Z. Yu; S. Blaak; G. C. M. Meijer; M. A. P. Pertijs; C. T. Lancée; J. G. Bosch; C. Prins; N. de Jong;
    In Annual Sensor Technology Workshop Sense of Contact,
    The Netherlands, April 2010. (Best Poster Award).

97. Design of a low power time-gain-compensation amplifier for a 2D piezoelectric ultrasound transducer
    J. Yao; Z. Yu; M. A. P. Pertijs; G. C. M. Meijer; C. T. Lancee; J. G. Bosch; N. de Jong;
    In Proc. IEEE International Ultrasonics Symposium (IUS),
    IEEE, pp. 841‒844, October 2010. DOI: 10.1109/ultsym.2010.5935775
    
    Abstract: ...

    In this paper, a programmable time-gain compensation amplifier dedicated to a 2D piezoelectric ultrasound transducer is presented. It uses an open-loop amplifier structure consisting of a voltage-to-current converter and a current-to-voltage converter. The circuit has been designed in a standard 0.35-μm CMOS process. Simulation and measurement results show that gains of 0dB, 12dB, 26dB and 40dB can be achieved for input signals centered at 6MHz with 80dB dynamic range (100μV to 1V). The measured gain errors at 6MHz are below 1dB for all gain settings. The amplifier consumes only 130μW when driving a 250fF load.

98. Design of a micro beamformer for a 2D piezoelectric ultrasound transducer
    S. Blaak; Z. Yu; G.C.M. Meijer; C.T. Lancee; J.G. Bosch; N. de Jong;
    In M Pappalardo (Ed.), Proceedings 2009 IEEE International Ultrasonics Symposium,
    IEEE, pp. 1338-1341, 2009. NEO.

99. Rapid 3D transesophageal echocardiography using a fast rotating multiplane transducer
    K. Nathanail; M. van Stralen; C.A. Prins; F. van den Adel; P.J. French; N. de Jong; A. van der Steen; J.G. Bosch;
    In s.n. (Ed.), Proceedings of the IEEE symposium, Beijing 2008,
    IEEE, pp. 1-4, 2008.

100. Design constraints of the interface electronics for an ultrasonic matrix transducer for 3D transesophageal echocardiography
     Z. Yu; G.C.M. Meijer; C.A. Prins; N. de Jong; H. van den Bosch;
     In s.n. (Ed.), Proceedings of sense of contact X,
     Sense of Contact 2009, pp. 1-4, 2008.

101. Magneetveldsensor, drager van een dergelijke magneetveldsensor en een kompas, voorzien van een dergelijke magneetveldsensor.
     J. van der MeerC; F.R. Riedijk; P.C. de Jong; A.W. van Herwaarden;
     2005. Xensor Integration B.V. te Delfgauw; 1025089; Xensor Integration B.V. te Delfgauw.

102. On-line electrical impedance measurement for monitoring blood viscosity during on-pump heart surgery
     G.A.M. Pop; T.L.M. de Backer; M. de Jong; P.C. Struijk; L. Moraru; Z.Y. Chang; H.G. Goovaerts; C.J. Slager; AJJC bogers;
     European Surgical Research: clinical and experimental surgery,
     Volume 36, Issue 5, pp. 259-265, 2004.

103. CMOS quad spinning-current hall-sensor system for compass application
     J. van der MeerC; F.R. Riedijk; P.C. de Jong; E.A. van Kampen; M.J. Meekel; J.H. Huijsing;
     In s.n. (Ed.), Proceedings of IEEE Sensors, 2004,
     IEEE, pp. 1434-1437, 2004. niet eerder opgevoerd - sb.

104. 40.1: Smart silicon sensors-examples of Hall-effect sensors
     P.C. de Jong; F.R. Riedijk; J. van der Meer;
     In Proceedings of IEEE sensors 2002: first IEEE international conference on sensors,
     IEEE, pp. 1440-1444, 2002. CD-Rom.

105. The influence of electric-field bending on the nonlinearity of capacitive sensors
     X. Li; G. de Jong; G.C.M. Meijer;
     IEEE Transactions on Instrumentation and Measurement,
     Volume 49, Issue 2, pp. 256-259, 2000.

106. A high-temperature electronic system for pressure-transducers
     P.C. de Jong; G.C.M. Meijer;
     IEEE Transactions on Instrumentation and Measurement,
     Volume 49, Issue 2, pp. 365-370, 2000.

107. Integrated interfaces for low-cost multiple-sensor systems
     G.C.M. Meijer; F.M.L. van der Goes; P.C. de Jong; X. Li; F.N.Toth;
     Journal of Intelligent Material Systems and Structures,
     Volume 10, pp. 105-115, 1999.

108. A smart accurate presure-transducer for high-temperature applications
     P.C. de Jong; G.C.M. Meijer;
     {V Piuri}; {M Savino} (Ed.);
     IEEE, , pp. 309-314, 1999.

109. The effect of electric-field bending on the linearity of capacitive position sensors with various elecrode structures
     X. Li; G. de Jong; G.C.M. Meijer;
     {V Piuri}; {M Savino} (Ed.);
     IEEE, , pp. 1348-1351, 1999.

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