5F-2 Packaging and Design of Reconfigurable Arrays for Volumetric Imaging

2014 Symposium on VLSI Circuits Digest of Technical Papers

Sodini

2014

This work presents a scalable Column-Row-Parallel ASIC architecture for 3D wearable / portable medical ultrasound. It leverages programmable electronic addressing to achieve linear scaling for both hardware interconnection and software data acquisition. A 16x16 transceiver ASIC is fabricated and flip-chip bonded to a 16x16 capacitive micromachined ultrasonic transducer (CMUT) to demonstrate the compact, low-power front-end assembly. A 3D plane-wave coherent compounding algorithm is designed for fast volume rate (62.5 volume/s), high quality 3D ultrasonic imaging. An interleaved checker board pattern with I&Q excitations is also proposed for ultrasonic harmonic imaging, reducing transmitted second harmonic distortion by over 20dB, applicable to nonlinear transducers and circuits with arbitrary pulse shapes.Each transceiver circuit is element-matched to its CMUT element. The high voltage transmitter employs a 3-level pulse-shaping technique with charge recycling to enhance the power efficiency, requiring minimum off-chip components. Compared to traditional 2-level pulsers, 50% more acoustic power delivery is obtained with the same total power dissipation. The receiver is implemented with a transimpedance amplifier topology and achieves a lowest noise efficiency factor in the literature (2.1 compared to a previously reported lowest of 3.6, in unit of mP a · mW/Hz). A source follower stage is specially designed to combine the analog outputs of receivers in parallel, improving output SNR as parallelization increases and offering flexibility for imaging algorithm design. Lastly, fault-tolerance is incorporated into the transceiver to deal with faulty elements within the 2D MEMS transducer array, increasing yield for the system assembly.

Section: Annular Ring Apertures For Forward-looking Imaging Applicationsmentioning

confidence: 99%

A Column-Row-Parallel ASIC architecture for 3D wearable / portable medical ultrasonic imaging

Chen

2014 Symposium on VLSI Circuits Digest of Technical Papers

Sodini

2014

“…Meanwhile, it has been known that capacitive micro-machined ultrasonic transducer (CMUT) technologies provide unique opportunities to minimize the size and cost of ultrasound scanners by fabricating and interconnecting the front-end circuits into CMUT array with higher performance in terms of features and image qualities [ 27 , 28 , 29 ]. Moreover, CMUT has been pointed out as a promising technology for large range of applications including medical diagnosis or treatment [ 27 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Orthogonal Chirp Coded Excitation in a Capacitive Micro-machined Ultrasonic Transducer Array for Ultrasound Imaging: A Feasibility Study

2019

Sensors

It has been reported that the frequency bandwidth of capacitive micro-machined ultrasonic transducers (CMUTs) is relatively broader than that of other ceramic-based conventional ultrasonic transducers. In this paper, a feasibility study for orthogonal chirp coded excitation to efficiently make use of the wide bandwidth characteristic of CMUT array is presented. The experimental result shows that the two orthogonal chirps mixed and simultaneously fired in CMUT array can be perfectly separated in decoding process of the received echo signal without sacrificing the frequency bandwidth each chirp. The experimental study also shows that frequency band-divided orthogonal chirps are successfully compressed to two short pulses having the −6 dB axial beam-width of 0.26- and 0.31-micro second for high frequency and low frequency chirp, respectively. B-mode image simulations are performed using Field II to estimate the improvement of image quality assuming that the orthogonal chirps designed for the experiments are used for simultaneous transmission multiple-zone focusing (STMF) technique. The simulation results show that the STMF technique used in CMUT array can improve the lateral resolution up to 77.1% and the contrast resolution up to 74.7%, respectively. It is shown that the penetration depth also increases by more than 3 cm.

“…Recent research studies on CMUT technologies provide unique opportunities to minimize the size and cost of ultrasound scanners by fabricating and interconnecting the front-end circuits into CMUT arrays with higher performance in terms of features and image qualities [1 ]- [3]. Moreover, CMUTs have been pointed out as a promising technology for large range of applications, including medical diagnosis or treatment [1], [4].…”

Section: Introductionmentioning

confidence: 99%

An experimental study on coded excitation in CMUT arrays to utilize Simultaneous Transmission Multiple-zone Focusing method with frequency divided sub-band chirps

2013 IEEE International Ultrasonics Symposium (IUS)

et al. 2013

The frequency bandwidth of CMUTs (capacitive micromachined ultrasonic transducers) is known as relatively broader than that of other ultrasonic transducers. To utilize the wide bandwidth characteristic of the CMUT arrays, in this paper, we report on coded excitation techniques in the CMUT array. Through simulations, STMF (Simultaneous Transmit Multiple zone Focusing) based ultrasound imaging techniques using orthogonally frequency-divided chirp signals are investigated. In the simulations, the fr equency divided sub-band chirps that have orthogonal property are designed within the frequency bandwidth of the CMUT arrays, and simultaneously fired on multiple ranges, in which each signal is focused at a different range, in one transmission event. This paper also presents ultrasound images through a modulation and demodulation process of orthogonal sub-band coded signals. Experiments on the chirp-coded excitation in CMUT arrays are reported in this paper as a feasibility study of the FDMA (frequency division multiple access) like STMF method. In the experiment, mixed two orthogonal chirp signals are simultaneously fired with the CMUT arrays and the received signals are successfully separated into two compressed signals.