Development of a MEMS microwave switch and application to adaptive integrated antennas

Adaptive integrated antennas are serious candidates for achieving the performance requirements of next-generation, broadband, wireless systems. This paper reports on the development of a microelectromechanical system (MEMS) shunt switch and its application to reconfigurable patch antennas. The micromachining procedure employs hexa-methyldisilizane (HMDS) as an anti-stiction surface treatment, significantly increasing the process yield. A MEMS shunt switch was designed for 10-20 GHz operation in a coplanar waveguide (CPW) regime. At 20 GHz, the insertion loss of the switch in the on-state was measured to be 0.25 dB, while an isolation of 10 dB was obtained in the off-state. Further improvement in the off-state isolation appears possible. The MEMS switch is applied to a novel co-planar patch antenna configuration in order to achieve adaptive radiation characteristics. A 30 GHz patch design shows in simulation a phase shift of 70 degrees between the two operating states.