A high performance MEMS miniature tunable bandpass filter

A miniature tunable 3-pole filter is fabricated using coplanar waveguide (CPW) transmission-tines on glass substrate (C/sub r/ = 4.6, tan /spl delta/ = 0.006) and an array of RF-MEMS varactors. The filter is tuned using a bias voltage of 0-80 Volts. The filter is /spl sim/3.6 mm long and gives a near ideal frequency response. A tuning range of 14% from 18.6 to 21.4 GHz was achieved, with a constant fractional bandwidth of 7.4 /spl plusmn/ 0.1% and a mid-band insertion loss of 3.85-4.15 dB.