Microscale ultrahigh-frequency resonant wireless powering for capacitive and resistive MEMS actuators
Microscale ultrahigh-frequency resonant wireless powering for capacitive and resistive MEMS actuators
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用于电容式和电阻式 MEMS 执行器的微型超高频谐振无线供电
DOI：
10.1016/j.sna.2018.03.020
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Kaiser Andreas
中科院分区：
文献类型：
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作者：
Mita Yoshio;Sakamoto Naoyuki;Usami Naoto;Frapp? Antoine;Higo Akio;Stefanelli Bruno;Shiomi Hidehisa;Bourgeois Julien;Kaiser Andreas
本文提出了一种用于微机电系统（MEMS）执行器的多功能芯片级无线驱动方法。 MEMS 执行器被集成为耦合 LCR 谐振电路的电气组件，并对通过超高频 (UHF) 射频 (RF) 波发送的能量进行整流。使用所提出的方法远程驱动两种类型的执行器：用作谐振接收器电路的 R 组件的热（双压电晶片）执行器和用作谐振接收器电路的 C 组件的电容（梳状驱动）执行器。我们演示了 13Ω 热执行器的远程驱动，传输 7.05mW 功率，功率效率为 15.8%。这是通过使用距离为 90μm 的耦合 500μm 直径 5.5 匝平面线圈天线实现的。当使用阻抗匹配配置（Zo=50Ω）时，在65μm距离上测得的效率为55.6%，比简单电感耦合的效率高8.2倍。所提出的方法可应用于未来的部署场景，其中脆弱的 MEMS 被放置在系统顶部，并且必须直接与环境连接（因此容易损坏）。作者建议在一个芯片上单片制造 MEMS 和能量接收器电路，并将它们放置在另一个能量发射器芯片上。由此，MEMS芯片可以避免电馈通，使得(a)MEMS芯片在损坏时可以容易地更换，并且(b)MEMS芯片可以超越布线电缆的限制。文章强调了四个特点：(1) MEMS 本身可以对 RF 能量进行整流，因为 MEMS 执行器的控制方程涉及电压和/或电流的平方，从而确保比使用额外整流组件（例如二极管）的任何其他 RF 收发器电路更高的系统级效率。 (2)发射器和接收器均使用相同设计的线圈，其尺寸与MEMS执行器的尺寸相当(数百微米)。此外，与传统发射机 (fs≈MHz) 相比，由于自谐振频率 (fs>GHz) 高得多，因此它们可以在 UHF 下运行。此外，通过使用LCR谐振电路，由于LC谐振，不仅可以(3)提高传输效率，还可以(4)倍增电容式MEMS致动器的驱动电压。电压倍增对于静电 MEMS 操作非常有用，因为运动与 MEMS 电容上的电压的平方成正比。本文介绍了热（电阻）和静电（电容）执行器的无线操作的全面设计、实现和演示。远程操作包括无机械谐振的 MEMS 开关键控以及正弦信号的幅度调制以激发 MEMS 的机械谐振频率。
This paper presents a versatile chip-level wireless driving method for microelectromechanical system (MEMS) actuators. A MEMS actuator is integrated as an electrical component of a coupled LCR resonant circuit, and it rectifies the energy sent through an ultrahigh-frequency (UHF) radio frequency (RF) wave. Two types of actuators were remotely driven using the proposed method: thermal (bimorph) actuators used as the R component and capacitive (comb-drive) actuators used as the C component of a resonant receiver circuit. We demonstrated the remote actuation of a 13 Ω thermal actuator transferring 7.05 mW power with a power efficiency of 15.8%. This was achieved using coupled 500 μm diameter 5.5-turn planar coil antennas over a distance of 90 μm. When an impedance-matching configuration (Zo= 50 Ω) was used, the efficiency over a distance of 65 μm was measured to be 55.6%, which was 8.2 times greater than that of simple inductor coupling. The proposed method can be applied to future deployment scenarios, where fragile MEMS are placed on top of a system and must directly interface with the environment (thus, being prone to break). The authors propose to fabricate MEMS and energy receiver circuits monolithically on a chip, and place them on another energy transmitter chip. Thereby, the MEMS chip can avoid electrical feedthrough so that (a) the MEMS chip is easily replaceable if it breaks, and (b) the MEMS chip can move beyond wiring cable limitations. Four features are underlined in the article: (1) MEMS itself can rectify the RF energy owing to the fact that the governing equation of the MEMS actuator involves the square of the voltage and/or current, thereby, ensuring higher system-level efficiency than any other RF transceiver circuits using additional rectifying components (e.g., diodes). (2) Both the transmitter and receiver use coils of the same design, whose sizes are equivalent to those of the MEMS actuators (hundreds of micrometers). Moreover, they can be operated at UHF, owing to the much higher self-resonant frequency (fs> GHz) when compared to conventional transmitters (fs≈ MHz). In addition, by using LCR resonant circuits, it is possible to not only (3) increase the transmission efficiency but also (4) multiply the driving voltage of the capacitive MEMS actuator, because of LC resonance. Voltage multiplication is quite useful for electrostatic MEMS operations because the movement is proportional to the square of the voltage across the MEMS capacitance. Comprehensive designs, implementations, and demonstrations of wireless operation are presented in this paper, for both thermal (resistive) and electrostatic (capacitive) actuators. Remote operation includes on–off-keying for MEMS without mechanical resonance and amplitude modulation of sinusoidal signals to stimulate the mechanical resonant frequency of MEMS.