Micromechanical Power Amplifier (NEMS)

Clark Nguyen1 and Elad Alon

Defense Advanced Research Projects Agency Grant No. NBCH1090001

This project aims to explore nanomechanical methods for realizing on-chip power amplifiers and power converters with potential for substantially higher efficiencies than attainable via conventional transistor technology. The key to achieving this is a new micromechanical switching device, dubbed the "resoswitch" [1][2], that harnesses the resonance and nonlinear dynamical properties of its mechanical structure to greatly increase switching speed and cycle count (even under hot switching) by large factors over existing RF MEMS switches, while also lowering the required actuation voltage to CMOS-compatible levels. The resoswitch further does all this with a substantially lower input capacitance than transistor counterparts for the same switch "on" resistance, And all this while also substantially reducing the input capacitance needed to achieve a low on-resistance compared with that required via semiconductor power transistors. This reduction capacitance (in both "on" and "off" states) gives the resoswitch a switch figure of merit orders magnitude better than achievable by transistor counterparts, and this should translate to higher efficiency when used in switched-mode power amplifier and power converter circuits. The planned circuit implementations for these functions are largely mechanical in nature, comprised of structures like that shown in the figure below, which presents a mechanical displacement amplifier circuit [3] instrumental to attaining sustained power gain. This effort is supported by the Defense Advanced Research Projects Agency (DARPA) under the Nano Electro Mechanical Systems (NEMS) program.

Figure 1
Figure 1: Scanning Electron Micrograph (SEM) of a micromechanical displacement amplifier circuit instrumental to attaining sustained power gain via on-chip mechanical means.

Y. Lin, W.-C. Li, Z. Ren, and C. T.-C. Nguyen, “The micromechanical resonant switch (“resoswitch”),” Tech. Digest, 2008 Solid-State Sensor, Actuator, and Microsystems Work-shop, Hilton Head, South Carolina, June 1-5, 2004, pp. 40-43.
Y. Lin, W.-C. Li, Z. Ren, and C. T.-C. Nguyen, “A resonance dynamical approach to faster, more reliable micromechanical switches,” Proceedings, 2008 IEEE Int. Frequency Control Symp., Honolulu, Hawaii, May 19-21, 2008, pp. 640-645.
Y. Lin, W.-C. Li, I. Gurin, S.-S. Li, Y.-W. Lin, Z. Ren, B. Kim, and C. T.-C. Nguyen, “Digitally-specified micromechanical displacement amplifiers,” the 15th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (Transducers’09), Denver, Colorado, June 21-25, 2009, pp. 781-784.

1Principal Investigator