Compact High-Power SPST and SP4T RF MEMS Metal-Contact Switches

This paper presents the design and characterization of compact high-power RF microelectromechanical system single-pole single-throw (SPST) and single-pole four-throw (SP4T) metal-contact switches. The SPST design results in a contact force of 1.9-2.8 mN at 80-90 V distributed over eight contacts and using four independent quadrants for actuation. The SP4T is a derivative of the SPST and results in a contact force of 0.45-0.7 mN per switch at 80-90 V. S-parameter measurements show an up-state capacitance of 70 and 17 fF along with a down-state resistance of 1-2 and 2-4 Ω using Au-to-Ru contacts for the SPST and SP4T switches, respectively. The switch pull-in and release voltages are 50 and 45 V, respectively, and the switching time is t on ~ 10 μs and t off ~ 2 μs. The SPST and SP4T are capable of handling 10 and 2 W up to 100 million cycles, and the SPST has been tested with 30 W of power up to 30 million cycles before failure (all cold switched). The application areas are in compact high-power applications such as wireless communication systems and base-stations.