The radial bulk annular resonator: towards a 50Ω RF MEMS filter

Abstract

This paper presents a new electrostatic RF MEMS resonator design: the radial bulk annular resonator (RBAR). The RBAR utilizes the bulk radial resonant modes of an annulus. The theory behind the RBAR, and its predecessor the bulk longitudinal resonator (BLR), will be developed and discussed. It is found that the RBAR is capable of achieving an arbitrarily low motional resistance for any desired resonant frequency at the cost of increased average annular radius. This feature makes the RBAR attractive for minimizing insertion loss in bandpass filters.