Monolithic Millimeter-Wave MEMS Waveguide Switch

Here, for the first time, a monolithic wafer-level micro-electro-mechanical systems (MEMS) waveguide switch for millimeter-wave application is presented. The switch is based on the monolithic integration of MEMS actuators (cantilever beams) inside the waveguide channel. The highly deflected beams are electrostatically actuated to provide ON and OFF states. In the OFF state, the beams are pushing against the upper inner wall of the waveguide to provide a short circuit, while the actuators are rolled flat to allow for maximum signal propagation during the ON state. The switch illustrates an excellent wideband RF performance, with an insertion loss as low as 0.2 dB in the ON state, and isolation of better than 22 dB in the OFF state, for the entire 60-75 GHz frequency band. A low-loss waveguide to CPW transition is also designed and integrated with the switch, which exhibits less than 1.1 dB loss for a back-to-back configuration across the band, and enables the on-wafer characterization of the entire structure.