Microelectromechanical-Systems-Based Switches for Power Applications

Keimel, Chris; Claydon, Glenn; Li, Bo; Park, John N.; Valdes, Marcelo E.

doi:10.1109/tia.2012.2199949

Cited by 31 publications

(9 citation statements)

References 12 publications

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“…A representative side view of the MEMS structure is shown in Figure A displaying the method of operation, as the switch is actuated the beams make contact with the central conductor providing a connection between RF a and RF b in the circuit schematic model. More details on the device structure are provided in Keimel et al To compare the behavior of both PIN diode and MEMS under the higher RF transmit power conditions experienced in whole‐body MRI, a bench‐top test was set up. A pulse‐modulated signal of 60 MHz with pulse duration of 0.2 ms (duty cycle 0.02%) was generated by a WS8352‐Taber waveform generator.…”

Section: Methodsmentioning

confidence: 99%

“…Recent improvements in the technology for MEMS switches and associated driver circuitry has allowed increased switching speed, better power handling and reduced insertion loss, so that MEMS switches have been successfully demonstrated for coil decoupling and reconfigurable RF coils in MRI. However, MEMS are not well established or characterized for use in the MRI environment when compared with PIN diodes, so both devices are systematically compared here.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Maunder

Rao

Robb

et al. 2018

Magnetic Resonance in Med

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PurposeTo evaluate the performance of micro‐electromechanical systems (MEMS) switches against PIN diodes for switching a dual‐tuned RF coil between 19F and 1H resonant frequencies for multi‐nuclear lung imaging.MethodsA four‐element fixed‐phase and amplitude transmit–receive RF coil was constructed to provide homogeneous excitation across the lungs, and to serve as a test system for various switching methods. The MR imaging and RF performance of the coil when switched between the 19F and 1H frequencies using MEMS switches, PIN diodes and hardwired configurations were compared.ResultsThe performance of the coil with MEMS or PIN diode switching was comparable in terms of RF measurements, transmit efficiency and image SNR on both 19F and 1H nuclei. When the coil was not switched to the resonance frequency of the respective nucleus being imaged, reductions in the transmit efficiency were observed of 32% at the 19F frequency and 12% at the 1H frequency. The coil provides transmit field homogeneity of ±12.9% at the 1H frequency and ±14.4% at the 19F frequency in phantoms representing the thorax with the air space of the lungs filled with perfluoropropane gas.ConclusionMEMS and PIN diodes were found to provide comparable performance in on‐state configuration, while MEMS were more robust in off‐state high‐powered operation (>1 kW), providing higher isolation and requiring a lower DC switching voltage than is needed for reverse biasing of PIN diodes. In addition, clear benefits of switching between the 19F and 1H resonances were demonstrated, despite the proximity of their Larmor frequencies.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Maunder

Rao

Robb

et al. 2018

Magnetic Resonance in Med

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“…For the sMEMS REC, the switch is closed in the reception phase. It can then be considered as a significant 0.5 Ω to 1 Ω parasitic resistance [31], [37] in the loop that should be compared with the loop size and its equivalent electrical resistance. This explains the experimental 0.62 ratio of Q-values between the sMEMS REC and a REC without any decoupling circuit.…”

Section: Discussionmentioning

confidence: 99%

“…1-d). More details about the MEMS and MDC information were provided in previous work [37]. To evaluate the MEMS performances for active decoupling of RECs, two different active decoupling REC configurations with MEMS in series (sMEMS REC) and MEMS in parallel (pMEMS REC) to the loop were built and assessed.…”

Section: A Rec Prototypesmentioning

confidence: 99%

Serial and Parallel Active Decoupling Characterization Using RF MEMS Switches for Receiver Endoluminal Coils at 1.5 T

Raki¹,

Koon²,

Saniour³

et al. 2020

IEEE Sensors J.

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MEMS (Micro Electro Mechanical System) switches were assessed and compared to PIN diode in fulfilling the task of active decoupling of Receiver Endoluminal Coils (RECs). Three prototype RECs with the PIN diode in parallel (pPIN), MEMS in parallel (pMEMS) and MEMS in series (sMEMS) with the REC loop were built. Quality factors (Q-values), decoupling efficiency and switching delays were characterized on bench and Signal-to-Noise Ratios (SNRs) established on images at 1.5 T. Q-values were equal to 62.5, 41.2 and 65.1 for pPIN, sMEMS and pMEMS, respectively. In the decoupled state, reflection coefficients S11 and S21 at resonance frequency both indicated proper decoupling. Switching delays were less than 0.7 µs and 10 µs for pPIN and MEMS RECs, respectively. Decoupling/coupling delays of MEMS remained compatible with most Magnetic Resonance (MR) clinical applications. For all prototypes, MR images displayed no signal saturation and similar elliptical image sensitivity patterns. No artifacts due to active decoupling failure were observed. Mean SNR values obtained with pMEMS REC were higher than those obtained with sMEMS REC but lower than with pPIN REC because of the use of additional instrumentation to render the scanner compatible with the MEMS utilization. MEMS in parallel are an interesting alternative to PIN diode for decoupling and could lead to better SNR with a compatible MR system (dedicated control signal). The MEMS in series can be used for both decoupling and reconfiguration of the REC loop geometry for colon wall examination.

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“…In particular, microelectromechanical systems (MEMS) represent an effort of this evolutionary engineering and have enabled many types of sensors, actuators, and systems to be reduced in size, exploiting microfabrication while often improving device performance [2]. For example, MEMS has miniaturized mechanical switches [3,4,5,6,7], chemical and physical sensors [8,9,10,11,12], display mirrors [13,14,15,16,17,18], and power generators [19,20,21,22]. A typical microfabrication process for MEMS encompasses photolithography to form a masking layer for subsequent processes, physical and chemical deposition to create a target material layer, and dry or wet etching to pattern the deposited layer.…”

Section: Introductionmentioning

confidence: 99%

Micro-LEGO for MEMS

Kim

2019

Micromachines

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The recently developed transfer printing-based microassembly called micro-LEGO has been exploited to enable microelectromechanical systems (MEMS) applications which are difficult to achieve using conventional microfabrication. Micro-LEGO involves transfer printing and thermal processing of prefabricated micro/nanoscale materials to assemble structures and devices in a 3D manner without requiring any wet or vacuum processes. Therefore, it complements existing microfabrication and other micro-assembly methods. In this paper, the process components of micro-LEGO, including transfer printing with polymer stamps, material preparation and joining, are summarized. Moreover, recent progress of micro-LEGO within MEMS applications are reviewed by investigating several example devices which are partially or fully assembled via micro-LEGO.

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Microelectromechanical-Systems-Based Switches for Power Applications

Cited by 31 publications

References 12 publications

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils

Serial and Parallel Active Decoupling Characterization Using RF MEMS Switches for Receiver Endoluminal Coils at 1.5 T

Micro-LEGO for MEMS

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