Electrostatic RF MEMS tunable capacitors with analog tunability and low temperature sensitivity

This work presents novel RF MEMS tunable capacitors with very low temperature sensitivity. The designs have separate and interdigitated RF and actuation electrodes which prevents dielectric charging under high actuation voltages. It also increases the capacitance ratio and the tunable analog range. Two devices with different mechanical operating principles are fabricated on a quartz substrate and result in a capacitance ratio 2.8–3.3 (Cmin=90–100 fF, Cmax=280–310 fF) and with a Q 100 at 5 GHz. The designs also exhibit measured pull-in voltage variation of 50 mV/oC at 20–120oC.