Parallel-contact Rf Mems Switches

Micromachining and microelectromechanical systems (MEMS) are among the most promising enabling technologies for developing low-power low-cost miniaturized RF components for high-frequency applications. RF MEMS switches are of interest because of their outstanding RF performance such as low insertion loss, good isolation, linear characteristic and low power consumption, compared to FET and diode-based switches. Several universities and companies have developed RF MEMS switches in the last decade.This paper presents a metal-to-metal contact shunt RF MEMS switch used in frequencies from dc to 10GHz. The high-frequency analysis and design, fabrication and test of this switch are reported. Based on the simulation, the varied-width bridge structure is presented to improve the loss of the switch, which is an innovation of this paper. And the method of circuit parameters extracting from the S-parameters is also discussed. The circuit parameters extracting method is also a feature of this research work.Furthermore, the switch is fabricated on high-resistivity silicon substrate, based on the standard MMIC processes and combined with the experimental method in our laboratory. The basic process consists of waveguide/actuation-pad metallization, nitride passivation, sacrificial layer coating and airbridge construction.Finally, both experimental and theoretical data for the designed switches are presented. The actuation voltage of the fabricated switch is about 30V. The RF performance shows insertion loss of less than 0.2dB and isolation of greater than 22dB for the frequencies from dc to lOGHz. The isolation is even greater than 28dB below 5GHz.