Design and modeling of 4-bit MEMS switched-line phase shifter

Abstract

Design and Modeling of a 4-bit MEMS switched-line phase shifter, which is composed by MEMS SP4T switches and microstrip transmission lines, and works in X-band. Each MEMS SP4T switch is used to switch two different signal pathways: reference phase signal pathway and delayed phase signal pathway. Each MEMS SP4T switch consists of 4 contact type RF MEMS switches with cantilever beam movable contact structure. Schematic design of the phase shifter is given. Design details of its critical components, including the SP4T switches and the phase delay lines are also put forward. Electrical performance of the device is simulated by the ADS software. The simulation results show that: the return loss and insertion loss of SP4T switch are −36dB and −0.18 dB, at the center frequency 10GHz, return loss of each phase delay line in the phase shifter are all below −15dB, return loss of each phase delay line are between — 0.4 and — 0.8 dB. The RF MEMS phase shifter has advantages of miniaturization, low power consumption and high isolation degree.