Piezoelectric Tuned LTCC Bandpass Filters

A piezoelectrically tuned second order LTCC bandpass filter with 46% measured tuning range is presented. The filter incorporates a novel parallel-plate capacitor which is tuned by a piezoelectrically moved electrode. The center frequency of the filter shifts from 1.28 GHz to 1.8 GHz with a preserved insertion loss and quality factor