An improved design for parallel plate MEMS variable capacitors

A MEMS variable capacitor having additional carrier beams is proposed. The use of the carrier beams increases the capacitor's tuning range and prevents the top plate from collapsing at a tuning range of 50%. The tuning range was measured and found to be 410% at 1 GHz with a maximum DC bias voltage of 9.2 volt. The achievable tuning range exceeds that of the traditional parallel plate MEMS variable capacitors. The proposed MEMS variable capacitor is built using the PolyMUMPs process.