This paper presents a novel method to obtain high isolation for a wideband RF MEMS switch. The MIM shunt capacitive switch consists of two identical beams placed in parallel over floating metals of different lengths on the signal line of a CPW. With two beams in parallel, the effective resistance and inductance of the switch is lesser than a switch with only one beam. The decrease in resistance provides higher isolation at resonant frequency while the decrease in inductance provides higher isolation at frequencies beyond resonant frequency. While the increase in insertion loss due to two beams is insignificant, there is a substantial increase in isolation over a large band of frequency. A switch with two beams with isolation greater than 30 dB and insertion loss less than 0.5 dB in the range of 3 GHz to 30 GHz is demonstrated.

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Radio frequency (RF) microelectromechanical system capacitive shunt switch with metal-to-metal contact is designed, fabricated and tested with the aim of having very low insertion loss (<0.2 dB) for high frequencies. The switch is designed with two identical parallel side beams with no overlapping with the signal line. This design has an added advantage of removing the self-actuation issues at high RF power. The measured isolation offered by the switch is greater than 40 dB at the resonant frequency, and the resonant frequency can be easily tuned by changing the length of a thin floating metal layer beneath the signal line.