Study of Broadband Cryogenic DC-Contact RF MEMS Switches

A dielectric-free DC-contact RF microelectromechanical system (MEMS) switch is designed and tested at room temperature and cryogenic temperatures. The switch demonstrates a 1-?? contact resistance and 2 fF up-state capacitance at room temperature, with an insertion-loss less than 0.4 dB up to 50 GHz and less than 0.9 dB up to 75 GHz. The isolation is better than 24 dB up to 50 GHz and 18 dB up to 75 GHz at room temperature. At a cryogenic temperature of 1.6 K, the switch has an insertion loss less than 0.6 dB with isolation better than 24 dB up to 50 GHz. The effects of cryogenic temperatures on deformation of the cantilever beam, actuation voltage, and RF performance have been noted. The theoretical and experimental results of the switch performance are presented and compared.