A Liquid-Metal RF MEMS Switch with DC-to-40 GHz Performance

We report a low-loss shunt RF-MEMS switch based on solid-to-liquid contact. This switch uses electrowetting-on-dielectric (EWOD) actuation of a liquid-metal (LM) droplet confined by a microframe, allowing bounce-free operation and fast switching (60 mus). Carrying the inherent solution LM provides for the nagging contact reliability problem, this paper introduces a two-droplet design that allows a low-loss RF performance. We further describe the microfabrication process, and report the test results. The switch demonstrates better than 0.3 dB insertion loss and 20 dB isolation up to 40 GHz, achieving significant improvements over previous demonstrations.