Performance improvement of RF-MEMS capacitive switch via asymmetric structure design

摘要

This paper presents a new type of capacitive shunt RF-MEMS switch. In the proposed design, float metal concept has been utilized to make the asymmetric structure on either side of the transmission line to implement the switch. This novel structure is used to inductively tune the isolation in C, X and K-u bands. Isolation peaks of 42.63, 44.22 and 47.75 dB has been observed at 7.2, 8.8 and 16.5 GHz when left, right or both cantilevers are electro-statically actuated in the down-state respectively, whereas conventional switch has peak only in X-band. Switch shows an insertion loss better than 0.10 dB, a return loss below 23.93 dB up to 25 GHz as compared to 0.90 dB insertion loss and 8.02 dB of return loss in case of conventional device. Further, improvement of around 5 times in bandwidth, 50 % in the pull-in voltage and 16.7 % in device area have also been observed. The designed switch can be useful at device and sub-system level for the future multi-band communication applications.