Surface-Micromachined Capacitive RF Switches With Low Actuation Voltage and Steady Contact

Abstract

In this paper, we report fabrication and dynamic characterization of low-actuation-voltage capacitive radio frequency microelectromechanical systems (RF MEMS) switches with improved electromechanical performance. Electromechanical and electromagnetic modeling is used to modify the previously known geometries of switches and the number and size of holes in them to improve their overall dynamic characteristics. The switches are fabricated on a Pyrex glass substrate using a low-complexity four-mask surface micromachining process. These designs of MEMS switches require only 4.8-6.2 V as pull-in voltage. The dynamic behavior of these MEMS switches is investigated experimentally. Measured mechanical resonant frequency and quality factor are found to be in the range of 7.56-10.7 kHz and 1.1 to 1.2, respectively. Measured switching times for all the designs are 33-37 μs at their respective pull-in voltages. These switches show bounce-free switching during contact and fast settling after release. Two of the switch designs have insertion loss of less than 0.25 and 0.7 dB at 20 and 40 GHz, and isolation better than 30 dB. Close agreement between experimentally measured and simulation results demonstrates successful realization of fast-switching capacitive RF MEMS switches at low voltage. [2016-0152].