Piezoelectric RF MEMS switches and phase shifters

Abstract

Piezoelectric thin films were utilized to actuate cantilevers for a radio frequency (RF) microelectromechanical system (MEMS) switches. Using lead zirconate titanate (PZT) thin films, an RF MEMS series switch was designed and fabricated. The switch operates from -25°_C to 100°_C with no change in actuation voltage of 9V. The switch isolation is better than -20 dB and the insertion loss (-S21) less than 0.5 dB from DC to 40 GHz. In addition to improvements in switch performance, a 17 GHz, 2-bit reflection phase shifter has been demonstrated using PZT shunt switches operating at 15 V. Each of the 4 phase states are demonstrated with minimal phase error and an average insertion loss of 6.8 dB with a high of 8 dB for the longest phase state (limited by substrate losses highlighted in our previous work). Correcting the substrate loss reduces the insertion loss of the long phase state to less than 2 dB.