A 3V Operation RF MEMS Variable Capacitor using Piezoelectric and Electrostatic Actuation with Lithographical Bending Control

A 3 V operation RF MEMS variable capacitor using hybrid actuation of piezoelectric and electrostatic forces is presented. Bending of the piezoelectric actuator is controlled by a lithographical pattern formed on top of the actuator. The hybrid actuation and the optimized bending enabled 2.6 V pull- in voltage with the pull-out voltage as high as 2.0 V The measured capacitance ratio is 14.

1. INTRODUCTION

RF MEMS variable capacitor is regarded as a key component in next generation reconfigurable RF front-end systems for mobile handsets, thanks to its low loss, excellent linearity and broad operation frequency [1], [2]. Piezoelectric actuators are ideal for such applications due to its low actuation voltage and low power consumption [3]–[5]. The ability to operate at 3V is especially attractive for mobile handsets, because power consuming charge pumps can be eliminated. It is also effective in reducing the bias voltage noise.