A high-g low-voltage HARPSS tunable capacitor

This paper reports on the design, fabrication and testing of a low-voltage, high-g one-port tunable capacitor in single wafer low-resistivity silicon substrate for RF filtering applications. The tuning range of the parallel plate capacitor is measured to be 2:1 for a range of 2.5-5pF with a tuning voltage of only 2V. The electrical quality factor (g) of a 1 mm × 1.5mm, 60μm thick capacitor with a gap of 1 μm was measured to be 99 at 400MHz and 49 at 1GHz and the return loss was below 0.5dB. The self-resonance frequency is above 10GHz.