Mechanically robust single crystalline silicon (SCS) single-pole-double-throw (SPDT) MEMS switch and its application to dual-band wlan filter

In this paper, we present mechanically reliable single crystalline silicon (SCS) single-pole-double-throw (SPDT) MEMS switch and successfully demonstrate a dual-band WLAN filter having different two center frequencies of 2.4 and 5.2 GHz using the proposed SPDT switches. Two direct-contact type SPDT MEMS switches are placed on the input and output position of two filter banks. They control the signal path to select one frequency-band between two ones of the WLAN. In this filter, precise filter responses without loss of RF matching can be obtained since pre-designed two filter banks are separately selected by ON/OFF actuation of the SPDT switches. The switches and two filter banks are fabricated on a wafer by batch process, and the SiOG-based silicon process enables to make robust switches and filter structures. The SPDT switch shows symmetric configuration for each output port, and the insertion loss and input to output isolation for one path were measured to be 0.12 and 38.1 dB with the actuation voltage of 30 V, respectively. The measured center frequencies of the fabricated filter were 2.85 and 5.45 GHz, and the insertion losses were 2.4 dB at 2.85 GHz and 5.4 dB at 5.45 GHz, respectively.