A Novel Approach for Low Insertion Loss, Multi-band, Capacitive Shunt RF–MEMS Switch

Abstract

This paper presents a novel capacitive shunt RF-MEMS switch. In the proposed design, broadside bridge structure joined with two cantilevers on either side has been used to implement the switch. The transmission line and actuation electrodes under the bridge are designed in the interdigitated form to reduce the area. Switch shows an insertion loss better than 0.11 dB, a return loss below 23.67 dB up to 25 GHz. In down-state, three resonant peaks of 34.71, 34.33 and 40.7 dB at 10.4, 11.0 and 21.4 GHz have been achieved as compared to a single peak in the case of the conventional switch. The proposed device has a bandwidth of 2.2 GHz in X-band and 5.2 GHz in K-band. Bridge structure shows a pull-in voltage of 12.25 V, actuation time of 34.40 µs while cantilevers have 7.5 V and 57 µs. Further, the electrical equivalent model has been presented to represent the switch. The model has been implemented in commercially available software. A good agreement with the 3-D electromagnetic simulated results validates the presented model.