Electrothermally actuated RF MEMS switches suspended on a low-resistivity substrate

Abstract

This paper presents an electrothermally actuated lateral resistive-contact switch for application to low-gigahertz-band communication systems. It was manufactured on a standard low-resistivity substrate, and its RF performance was improved by suspending the structures 25 μm from the substrate, which is a strategy for future integration with active devices in the system-on-chip concept. Measured insertion losses are−0.26 dB at 1 GHz and −0.65 dB at 6 GHz, return losses are −29 dB at 1 GHz and −25 dB at 6 GHz, and isolations are −52 dB at 1 GHz and −26 dB at 6 GHz. The device is driven by a metal electrothermal actuator, which achieves large displacements and contact forces at much lower temperatures than traditional polysilicon electrothermal actuators. The RF power handling characteristics are also addressed and measured.