Demonstration of a tunable RF MEMS bandpass filter using silicon foundry process

A novel tunable microwave filter with tuning range of 13.8 GHz to 18.2 GHz fabricated using a standard silicon foundry process based on lowresistivity silicon substrate is reported. The filter effect has been realized by integrating two interdigitated comb capacitors with a straight line inductor. The tuning effect has been achieved by varying the capacitance value of the capacitors with a bimorph MEMS actuator. The structure in whole, measuring 1.5 mm × 3.3 mm, allows 27.5% continuous tuning and insertion loss ranging from 3.4 to 6 dB. The driving voltage ranges from 0 V to 0.36 V.