High tuning range and low pull-in voltage MEMS tunable capacitors filled with liquid crystal materials

This article demonstrates a new concept of micromechanical tunable capacitor with nematic liquid crystal (NLC) as the dielectric material. Compared to the typical parallel-plate tunable capacitor with air as dielectric material, the NLC device shows a significant improvement with smaller pull-in voltage (25.2 V vs. 13 V), larger capacitance tuning ratio (0.542 vs. 1.224), and smaller recovering (pull-out) voltage (17 V vs. 4 V). As a result, the micromechanical tunable capacitor with NLC material can be operated at a smaller actuation voltage with larger capacitance tuning ratio, which makes the device a great potential in the future.