An equivalent-circuit method for coupled-field modeling of distributed RF MEMS devices and packages

This paper presents an equivalent-circuit method for analyzing the coupled field behavior of packaged distributed radio frequency microelectromechanical system (RF MEMS) devices. A distributed RF MEMS phase shifter is taken as an analytic example. The whole structure of the packaged device is divided into fundamental elements. The thermo-mechanical, electrostatic and electromagnetic models for different functional elements are established, represented by electrical equivalents and then integrated by continuity conditions at the interfacial nodes. PSpice is used as a calculation platform. Experiments and finite element method (FEM) simulations are conducted to validate this method. The results from the three different approaches show good agreement. It is shown that thermally induced packaging effect has considerable influence on the phase shift performance of this kind of complex RF MEMS device.