Micromechanical RSSI Based on Force Interaction Derived Tapping Bandwidth Variation in VIBRO-IMPACT Resonators

This work demonstrates a micromechanical received signal strength indicator (RSSI) circuits based on CMOS-MEMS folded-beam comb-drive tapping-mode resonators. In particular, the tapping bandwidth of vibro-impact resonators that exhibits a linear growth as a function of input signal level when the dominant contact force transits from the attractive to repulsive force is used as RSSIs for ultra-low power indoor positioning reader applications. Based on CMOS-MEMS folded-beam comb-drive resonators, two designs are presented specifically for this purpose: (1) applying gap-narrowing technique to improve sensitivity, and (2) double-sided stoppers with different gap spacing to create digitized bandwidth vs. input signal strength for event-oriented positioning. These techniques would help to solve the power consumption and decoding problems of previous indoor localization method.