High-isolation CPW MEMS shunt switches - Part 1: Modeling

This paper, the first of two parts, presents an electromagnetic model for m embrane microelectromechanical systems (MEMS) shunt switches for microwave/ millimeter-wave applications. The up-state capacitance can be accurately mo deled using three-dimensional static solvers, and full-wave solvers are use d to predict the current distribution and inductance of the switch. The los s in the up-state position is equivalent to the coplanar waveguide line los s and is 0.01-0.02 dB at 10-30 GHz for a 2-mu m-thick Au MEMS shunt switch. It is seen that the capacitance, inductance, and series resistance can be accurately extracted from dc-40 GHz S-parameter measurements. It is also sh own that dramatic increase in the down-state isolation (20(+) dB) can be ac hieved with the choice of the correct LC series resonant frequency of the s witch. In part 2 of this paper, the equivalent capacitor-inductor-resistor model is used in the design of tuned high isolation switches at 10 and 30 G Hz,