Three-Dimensional RF MEMS Switch for Power Applications

This paper introduces a new concept in 3-D RF microelectromechanical systems switches intended for power applications. The novel switch architecture employs electrothermal hydraulic microactuators to provide mechanical actuation and 3-D out-of-plane silicon cantilevers that have both spring action and latching mechanisms. This facilitates an off-state gap separation distance of 200 mum between ohmic contacts, without the need for any hold power. Having a simple assembly, many of the inherent problems associated with the more traditional suspension-bridge and cantilever-type-beam architectures can be overcome. A single-pole single-throw switch has been investigated, and its measured on-state insertion and return losses are less than 0.3 dB up to 10 GHz and greater than 15 dB up to 12 GHz, respectively, while the off-state isolation is better than 30 dB up to 12 GHz. The switch works well in both hot- and cold-switching modes, with 4.6 W of RF power at 10 GHz and without any signs of degradation to the ohmic contacts.