Benchmarking the passive differential input technique to shielded GSG probes

Abstract

We have previously showed that feedthrough in MEMS resonators of generic mode shapes can be suppressed by as much as close to 40dB by applying a passive differential input technique. This paper compares the degree of feedthrough suppression achieved via the passive differential input technique against electrical measurements carried out using shielded GSG microwave probes. The shielded GSG microwave probes in themselves provide for excellent isolation between the input and output ports. The device under test was a square-extensional (SE) mode micromechanical resonator probed at 4 electrodes for actuation. Our results show, that despite as simple an implementation as it presents, the passive differential input technique offers additional 20dB suppression relative to the GSG probes.