High-Q RF MEMS capacitor with digital/analog tuning capabilities

Abstract

This paper presents an RF MEMS switchedcapacitor suitable for tunable filters and reconfigurable matching networks. The switched-capacitor contains design features that result in a tunable capacitance ratio of 5–7, a high-Q (≫ 100) at C to X-band frequencies, and excellent reliability performance. The switched-capacitor has been temperature cycled to 120° C with only a 3–4 V change in the pull-down voltage. The design also features a digital switched-capacitor mode and an analog tuning mode, making it ideal for precision tuning.