Pulse mode actuation-readout system based on MEMS resonator for liquid sensing

Abstract

A MEMS (Micro-Electro-Mechanical Systems) bulk disk resonator is applied for mass sensing under its dynamic mode. The classical readout circuitry involves sophisticated feedback loop and feedthrough compensation. We propose a simple straightforward non-loop pulse mode actuation and capacitive readout scheme. In order to verify its feasibility in liquid bio-chemical sensing environment, an experimental measurement is conducted with humidity sensing application. The measured resonant frequency changes 60kHz of 67.7MHz with a humidity change of 0~80%.