RF characteristics of dual-actuation CMOS-MEMS RF switches

The capacitive type of radio frequency micro-electromechanical systems (RF MEMS) switch is investigated for low driving voltages and low power consumption. The RF MEMS switch is actuated by electro-thermal forces and electrostatic forces at the same time, and then held the status by electrostatic forces only after driving. We also use complementary metal oxide semiconductor (CMOS) technology to integrate MEMS devices and integrated circuits (ICs) into a monolithic chip. The RF MEMS switch is fabricated using standard CMOS process, double poly-silicon four metal (2P4M), and the wet etching of MEMS fabrication is then used for post-processed. Experimental results show that the both actuation mechanisms, electro-thermal and electrostatic forces, are workable. The pull-in voltage of the switch for driving is about 7 volts. The insertion loss and the isolation of RF switch at a frequency of 5 GHz are 2.5 dB and 1.6 dB, respectively.