Design, fabrication and characterization of capacitive RF MEMS switches with low pull-in voltage

The dielectric charging caused by high actuation voltages is one of the reasons behind the poor reliability of capacitive MEMS switches. This paper reports the design, fabrication and characterization of an RF MEMS switch with a very low-actuation voltage and high isolation. The device is fabricated on a glass substrate using a four mask surface micromachining process. The electromechanical characterization reveals a very low pull-in voltage of 4.8 V for the fabricated device. The RF measurement results show an insertion loss of 0.55 dB and an isolation of -47.6 dB at 40 GHz. The excellent RF performance makes these switches a suitable choice for very high frequency (K-band and above) applications.