RF MEMS devices: a brave new world for RF technology

The design, fabrication, and behavior of a microelectromechanical (MEM) capacitive membrane microwave switching device is described. The switching element consists of a thin metallic membrane, which has two states, actuated or unactuated, depending on the applied bias. A microwave signal is switched on and off when the membrane is switched between the two states. The devices are electrostatically actuated and are therefore ultra low power. They also have very linear behavior with extremely low signal distortion. The switches show a very low insertion loss of 0.07 dB and an isolation of 35 dB at 40 GHz. A variety of RF phase shifters and tuning circuits have been fabricated using these switches and show world-class RF loss behavior. These devices offer the potential for building a new generation of low-loss high-linearity microwave circuits for a variety of phased antenna arrays for radar and communications applications.