Air-coupled capacitive micromachined ultrasonic transducers (CMUTs) based on annular cell geometry have recently been reported. Finite element analysis and experimental studies have demonstrated their significant improvement in transmit efficiency compared with the conventional circular-cell CMUTs. Extending the previous work, this paper proposed a lumped element model of annular-cell CMUTs. Explicit expressions of the resonance frequency, modal vector, and static displacement of a clamped annular plate under uniform pressure were first derived based on the plate theory and curve fitting method. The lumped model of an annular CMUT cell was then developed by adopting the average displacement as the spatial variable. Using the proposed model, the ratio of average-to-maximum displacement was derived to be 8/15. Experimental and simulation studies on a fabricated annular CMUT cell verified the effectiveness of the lumped model. The proposed model provides an effective and efficient way to analyze and design air-coupled annular-cell CMUTs.
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http://dx.doi.org/10.1016/j.ultras.2016.11.014 | DOI Listing |
Med Phys
January 2025
Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.
Background: Radiofrequency (RF) transmit arrays play a crucial role in various MRI applications, offering enhanced field control and improved imaging capabilities. Designing and optimizing these arrays, particularly in high-field MRI settings, poses challenges related to coupling, resonance, and construction imperfections. Numerical electromagnetic simulation methods effectively aid in the initial design, but discrepancies between simulated and fabricated arrays often necessitate fine-tuning.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC - Universidad de Zaragoza, Plaza San Francisco s/n, Zaragoza 50009, Spain.
A strategy toward the realization of a quantum spin processor involves the coupling of spin qubits and qudits to photons within superconducting resonators. To enable the realization of such hybrid architecture, here we first explore the design of a chip with multiple lumped-element LC superconducting resonators optimized for their coupling to distinct transitions of a vanadyl porphyrin electronuclear qudit. The controlled integration of the vanadyl qudit onto the superconducting device, both in terms of number and orientation, is then attained using the formation of nanosheets of a 2D framework built on the vanadyl qudit as a node.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India.
Quantum technology exploits fragile quantum electronic phenomena whose energy scales demand ultra-low electron temperature operation. The lack of electron-phonon coupling at cryogenic temperatures makes cooling the electrons down to a few tens of millikelvin a non-trivial task, requiring extensive efforts on thermalization and filtering high-frequency noise. Existing techniques employ bulky and heavy cryogenic metal-powder filters, which prove ineffective at sub-GHz frequency regimes and unsuitable for high-density quantum circuits such as spin qubits.
View Article and Find Full Text PDFCardiovasc Eng Technol
January 2025
School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Rm. 718, Philadelphia, PA, 19104, USA.
Purpose: Computational models of the cardiovascular system continue to increase in complexity. As more elements of the physiology are captured in multiscale models, there is a need to efficiently integrate subsystems. The objective of this study is to demonstrate the effectiveness of a coupling methodology, called functional mock-up interface (FMI), as applied to multiscale cardiovascular modeling.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Electronic Engineering, Hanyang University, Seoul, 04763, South Korea.
In this paper, a miniaturized 2 × 2 MIMO dual-wideband ground radiation antenna targeting Wi-Fi 6/6E/7 standards using 2.4 GHz, 5 GHz, and 6 GHz frequency bands with sufficient antenna performance was designed. The proposed antenna system contains four identical 4 mm × 6 mm antennas of the internal loop type and two identical 6 mm × 6 mm isolators containing lumped LC elements.
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