EMPIRICAL FORMULATION OF BRIDGE INDUC- TANCE IN INDUCTIVELY TUNED RF MEMS SHUNT SWITCHES

Abstract—This paper presents a substrate independent empirical formulation for the bridge inductance of inductively tuned RF MEMS shunt switches, allowing a systematic design approach to tune their isolation bands. Inductive tuning of RF MEMS switches is achieved by inserting recesses in the ground plane and meanders to the bridges, allowing the tuning of the isolation band of the switch from the X-band to the mm-wave band. The bridge inductance is first extracted from parametric EM simulations of the RF MEMS shunt switches and then fitted to the proposed formulations using empirical coefficients. The accuracy of the formulations is verified with the measurements on the switches that are fabricated using an in-house surface micromachining RF MEMS process on a 500-µm thick glass substrate. Measurement results verify that the bridge inductances can be determined by the provided empirical formulation. 1