Broadband ring-shaped PMUTS based on an acoustically induced resonance

Eovino, Benjamin E.; Akhbari, Sina; Lin, Liwei

doi:10.1109/memsys.2017.7863627

Cited by 34 publications

(16 citation statements)

References 8 publications

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“…The pMUT matrix is fabricated in the silicon wafer and consists of aluminum nitride (AlN) bimorph membranes that formed the active transducer layers [12], [18]. The cross section micro-scope image of the transducer and its crosssectional diagram are shown in Fig.…”

Section: B Pmut Analysismentioning

confidence: 99%

A 36-Channel Auto-Calibrated Front-End ASIC for a pMUT-Based Miniaturized 3-D Ultrasound System

Lee

Eovino

et al. 2021

IEEE J. Solid-State Circuits

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We present an area-and power-efficient applicationspecific integrated circuit (ASIC) for a miniaturized 3-D ultrasound system. The ASIC is designed to transmit pulse and receive echo through a 36-channel 2-D piezoelectric Micromachined Ultrasound Transducer (pMUT) array. The 36-channel ASIC integrates a transmitter (TX), a receiver (RX), and an analog-todigital converter (ADC) within the 250-μm pitch channel while consuming low-power and supporting calibration to compensate for the process variation of the pMUT. The charge-recycling high-voltage TX (CRHV-TX) in standard CMOS generates up to 13.2-V PP pulse while reducing 42.2% peak TX power consumption. Also, each CRHV-TX automatically calibrates excitation voltage according to acoustic pressure of pMUT. The dynamic-bit-shared ADC (DBS-ADC) shares the most significant bits (MSBs) among four channels based on the signal similarity between adjacent channels. The analog front end (AFE) with a received signal sensitivity indicator (RSSI) changes its gain adaptively in real time depending on input signal strength. The ASIC consumes 1.14-mW/channel average power with 1-kHz pulse repetition frequency (PRF) and three TX pulses per cycle. The ASIC in 0.18-μm 1P6M Standard CMOS has been verified with both electrical and acoustic experiments with a 6 × 6 pMUT array.

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Section: B Pmut Analysismentioning

confidence: 99%

A 36-Channel Auto-Calibrated Front-End ASIC for a pMUT-Based Miniaturized 3-D Ultrasound System

Lee

Eovino

et al. 2021

IEEE J. Solid-State Circuits

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“…There are two transduction mechanisms in MUTs: the capacitive [13] and piezoelectric scheme [14]. Performance enhancement studies can be summarized in two approaches; (1) optimal geometric designs such as collapse mode [15] in capacitive MUTs (cMUTs) or curved [16], ring [17], free [18] and pinned [19] boundary, bimorph [20] structures in piezoelectric MUTs (pMUTs); and (2) thin film materials with high piezoelectric properties such as PZT [21] and AlN [22]. In this study, pMUTs are investigated since they have shown prominent features in air applications such as no need for a bias voltage and the large displacement under the flexural vibration mode.…”

Section: Introductionmentioning

confidence: 99%

An Improved Lumped Element Model for Circular-Shape pMUTs

Pala

Lin

2022

IEEE Open J. Ultrason., Ferroelect., Freq. Contr.

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This paper presents an improved lumped element model for clamped, circular-shape, piezoelectric micromachined ultrasonic transducers (pMUTs). A small signal equivalent circuit is developed to include electrical, mechanical, and acoustic domains, which are analyzed separately and combined with the associated couplings. For the first time, a two-term mode shape approach is adapted to reveal intrinsic and extrinsic properties of a pMUT, such as equivalent circuit parameters, input impedance, velocity, displacement, bandwidth, quality factor, directivity, and the on-axis pressure in the near and far field. These properties are compared with prior reports in the literature and exact solutions, as well as Finite Element Method (FEM) simulations. The errors relative to exact solution for all these properties are below 0.5%. These improvements in error are from 5x to about 3 orders of magnitude better than those of prior works. As such, the improved model could be helpful in design and simulation tools for pMUTs.

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“…Compared to CMUT, PMUTs have a more simple structure and thus a robust fabrication process [ 5 ], generate higher acoustic beam intensity, and do not require any bias voltage, which is preferred in medical applications [ 6 ]. However, the bandwidth of PMUTs is very limited and precludes the device from most imaging applications, including pulse-echo imaging and those involving chirp waveforms or harmonic response applications [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…In mode-merging [ 8 ], a device with an appropriate structure design, such as a ring [ 7 ] or ribbon [ 9 ] shape, can generate two or more resonance peaks and overlap in one broad bandwidth, often exceeding 100% (−6 dB). However, such devices are challenging to design for high frequency (because the resonance peaks become relatively narrower) and the overlapping effect is sensitive to the mass density of the load [ 7 ]. Another approach better suited for high-frequency applications is using parallel multiple resonator cells with different working frequencies to form an effective element [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array

Wang

et al. 2021

Sensors

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Piezoelectric micromachined ultrasonic transducers (PMUT) are promising elements to fabricate a two-dimensional (2D) array with a pitch small enough (approximately half wavelength) to form and receive arbitrary acoustic beams for medical imaging. However, PMUT arrays have so far failed to combine the wide, high-frequency bandwidth needed to achieve a high axial resolution. In this paper, a polydimethylsiloxane (PDMS) backing structure is introduced into the PMUTs to improve the device bandwidth while keeping a sub-wavelength (λ) pitch. We implement this backing on a 16 × 8 array with 75 µm pitch (3λ/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (−6 dB) and has little influence on the impulse response sensitivity. By widening the transducer bandwidth, this backing may enable using PMUT ultrasonic arrays for high-resolution 3D imaging.

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Broadband ring-shaped PMUTS based on an acoustically induced resonance

Cited by 34 publications

References 8 publications

A 36-Channel Auto-Calibrated Front-End ASIC for a pMUT-Based Miniaturized 3-D Ultrasound System

A 36-Channel Auto-Calibrated Front-End ASIC for a pMUT-Based Miniaturized 3-D Ultrasound System

An Improved Lumped Element Model for Circular-Shape pMUTs

Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array

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