Motional impedance analysis: Bridging the ‘Gap’ in dielectric transduction

This paper presents an analytical model to estimate the motional resistance for partial air gap capacitively-transduced MEMS resonators. This model serves as a link between the well formulated analytical models for conventional air gap and internal dielectric transduction schemes, thereby helping decide which scheme is optimal for a given design frequency. Using this model, we simulate and experimentally verify the motional resistance for a 303MHz polysilicon disk resonator within a 5% range of accuracy.