Design and fabrication of a single membrane push-pull SPDT RF MEMS switch

In this paper, we report a new push-pull-type SPDT (single pole double throw) switch actuated by the combination of electromagnetic and electrostatic forces for low power and low voltage operation. The switch is initially actuated by large electromagnetic force to change its state and is held to maintain its state by applying electrostatic force to reduce static power consumption. The electromagnetic force can be easily generated at low voltage. The maximum actuation voltage is below 4.3 V and the required energy is 15.4 μJ per switching. It achieves signal isolation of −54 dB and insertion loss of −0.16 dB at 2 GHz, respectively. For 20 GHz operation, isolation and insertion loss were measured as −36 dB and −0.52 dB, respectively. The proposed SPDT switch combines two switching elements in a single structure, simplifying the overall structure and control signals and eliminating mismatches between the two switching elements. The dimension of the switch has been optimized using FEM simulation and analytical calculations. We have successfully carried out a lifetime test over more than 166 million cycles with the maximum actuation voltage below 4.3 V. (Some figures in this article are in colour only in the electronic version)