A Novel Interdigitated, Inductively Tuned, Capacitive Shunt RF - MEMS Switch for X and K Bands Applications

This paper presents a new type of capacitive shunt RF-MEMS switch. In the proposed design, interdigitation of signal lines with actuation electrodes is used to make a compact device. A bridge structure anchored in between ground planes and attached to two cantilevers on either side has been used to implement the switch structure. This novel structure is used to inductively tune the isolation peaks in X and K bands which is not possible with conventional approach. The designed switch shows an insertion loss of 0.01 dB to 0.11 dB over the frequency range from 1 to 25 GHz. Isolation of 34.71, 34.33, and 40.7 dB has been observed at 10.4 GHz, 11 GHz and 21.4 GHz when bridge is electro-statically actuated with either left, right or both cantilevers in the down state respectively. The bridge structure shows a pull-in voltage of 12.25 V and switching time of 34.40 mu s whereas left and right cantilevers have 7.5 V and 57 mu s. The designed device can be useful for the future multi-band communication applications.