Low-loss RF MEMS fixed free capacitive switch characterization

RF MEMS are small mechanical devices fabricated by photolithographic processes, which are used for elemental signal processing functions in RF and microwave, frequency circuits. The design of low loss RF MEMS fixed free capacitive switch is explained. The most common RF MEMS control component is a microwave transmission line switch, currently under development for applications requiring low insertion loss, high linearity, moderate switching speeds and low to moderate power. These shunt switches possess a movable metal membrane which pulls down onto a metal dielectric sandwich to form a capacitive switch. These switches exhibit low loss (<0.25 dB at 35 GHz) with good isolation (35 dB at 35 GHz).This paper gives the construction and performance of low loss RF MEMS Fixed Free switches at microwave and millimetre-wave frequencies (0.1 to 100 Ghz) and also describes the improvements in the design of the switch.