High Tuning Range Parallel Plate MEMS Variable Capacitors with Arrays of Supporting Beams

A novel MEMS variable capacitor, built with arrays of supporting beams, is proposed. The supporting beams create different restoring forces, as the top plate deflects, increasing the tuning range of the capacitor. The tuning range was measured and found to be 470% at 1 GHz with a maximum DC bias voltage of 10.2 volt. The achievable tuning range exceeds that of any known parallel plate MEMS variable capacitor. The proposed capacitor promises to achieve a higher tuning range by optimizing the supporting beams array configuration. The experimental MEMS variable capacitors are built using the PolyMUMPs process.