A Novel MEMS LC Tank for RF Voltage Controlled Oscillator(VCO)

A linearly tunable MEMS capacitor changing the overlap area and a high-Q electroplated solenoid inductor are developed. The single crystal silicon MEMS structure is bonded with the pyrex glass substrate to make the designed capacitor. The pyrex glass is adopted as a substrate instead of the silicon to reduce the RF losses through the substrate for both a capacitor and a inductor. The measured capacitor shows the nominal capacitance of 1.4 pF, 10 % tuning range at 2 GHz and the inductor has inductance between 1 nH and 5 nH, maximum Q factor over 10 at 2 GHz. The models are also developed and proven by Serenade software of Ansoft Corporation respectively.