Electrically Coupled MEMS Bandpass Filters

Abstract

This dissertation reports, for the first time, on the electrical coupling of microelectromechanical (MEM) resonators for high order bandpass filter synthesis. Electrical coupling of MEM resonators has a strong potential for extension of the operating frequency of MEM bandpass filters into the ultra high frequency (UHF) range and provides higher tunability and design flexibility compared to the mechanical coupling approach. Various schemes of electrical coupling are presented in this dissertation. Electromechanical models of clamped-clamped beam resonators, and various types of electrically coupled filters are presented. Lower frequency prototypes of electrically coupled filters with operating frequencies in the hundreds of kHz are implemented using micromechanical single crystal silicon clamped-clamped beam resonators. Measurement results are in good agreement with the developed electrical equivalent models of the filters. It is demonstrated that the characteristics of electrically coupled filters can be widely tuned by changing the DC polarization voltages.