A cryogenic broadband DC contact RF MEMS switch

A dielectric free DC contact RF microelectromechanical systems (MEMS) switch is designed and tested under room temperature and cryogenic temperature. The switch demonstrates a 1 Omega contact resistance and 2 fF up-state capacitance, and thus has an insertion-loss less than 0.4 dB up to 50 GHz and less than 0.9 dB up to 75 GHz at room temperature. The isolation is better than 24 dB up to 50 GHz and 18 dB up to 75 GHz at room temperature. At cryogenic temperature (77.5 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 actuation voltage and contact resistance have been noted. The theoretical and experimental results of the switch performance are presented and compared.