  A maskless post-processing technique for CMOS chips is developed that enables
the fabrication of RF MEMS parallel-plate capacitors with a high quality factor
and a very compact size. Simulations and measured results are presented for
several MEMS/CMOS capacitors. A 2-pole coupled line tunable bandpass filter
with a center frequency of 9.5 GHz is designed, fabricated and tested. A tuning
range of 17% is achieved using integrated variable MEMS/CMOS capacitors with a
quality factor exceeding 20. The tunable filter occupies a chip area of 1.2 x
2.1 mm2.
