Modeling, design and simulation of tunable band pass filter using RF MEMS capacitance and transmission line

Abstract

In this paper we have shown design of a RF MEMS band pass filter. A high capacitance ratio and low actuation voltage RF MEMS shunt switch was designed and modeled the switch as a variable capacitance. The capacitance can be varied as a function of the actuation voltage. The capacitance is modeled as a lumped component, as used in a conventional LC filter. The design uses a novel approach to implement both distributed transmission line and RF MEMS capacitance together to replace the lumped elements. The use of RF MEMS variable capacitance gives the flexibility of tuning the cut-off and center frequency of bandpass filter. In this paper we show a design of 5.8 GHz center frequency band pass filter using the theory of stepped impedance transmission line and MEMS capacitance filter.