A low-loss, single-pole, four-throw RF MEMS switch driven by a double stop comb drive

Abstract

Our goal was to develop a single-pole four-throw (SP4T) radio frequency microelectromechanical system (RF MEMS) switch for band selection in a multi-band, multi-mode, front-end module of a wireless transceiver system. The SP4T RF MEMS switch was based on an arrangement of four single-pole single-throw (SPST) RF MEMS switches. The SP4T RF MEMS switch was driven by a double stop (DS) comb drive, with a lateral resistive contact, and composed of single crystalline silicon (SCS) on glass. A large contact force at a low-drive voltage was achieved by electrostatic actuation of the DS comb drive. Good RF characteristics were achieved by the large contact force and the lateral resistive Au-to-Au contact. Mechanical reliability was achieved by using SCS which has no residual stress as a structure material. The developed SP4T RF MEMS switch has a drive voltage of 15 V, an insertion loss below 0.31 dB at 6 GHz after more than one million cycles under a 10 mW signal, a return loss above 20 dB and an isolation value above 36 dB.