Microwave modelling of radio frequency microelectromechanical rotary switches

In this study, both full 3D electromagnetic and equivalent circuit modelling of a radio frequency microelectromechanical systems (RF MEMS) single-pole eight-throw rotary switch are reported for the first time. Excellent agreement has been achieved between measurements and modelled performance for frequencies up to 12 GHz. In order to validate the effectiveness of the modelling, a 2-bit true time delay phase shifter having a centre frequency of 2 GHz has been demonstrated. The traditional topology of the switched delay line was adopted with two rotary switches employed for signal routing. This phase shifter represents the first ever application of any RF MEMS rotary switch. It is shown that the switch model can accurately predict the measured performance of the phase shifter, without the need for adding new circuit elements or tweaking of model parameters. The low measured root mean square deviations of insertion phase from the predicted responses increase as 1.38, 1.98, 2.58 and 3.48 when the phase states are stepped through 08, 908, 1808 and 2708, respectively.