An integrated tunable band-pass filter using MEMS parallel-plate variable capacitors implemented with 0.35μm CMOS technology

This paper presents an integrated tunable bandpass filter with RF MENIS varactors fabricated using the TSMC 0.35 mu m CMOS process. A maskless post-processing technique is developed which enables the fabrication of RF MENIS parallel-plate capacitors with a high quality factor and a very compact size. A 2-pole coupled line tunable bandpass filter with a center frequency of 9.5GRz and a 9% relative bandwidth is designed, fabricated and tested. A tuning range of 17% is achieved using integrated variable MENIS capacitors with a quality factor exceeding 20. The filter has an insertion loss of 5.66dB and occupies a chip area of 1.2 x 2.1 mm(2).