Piezoelectric transducer-controlled dual-mode switchable bandpass filter

A piezoelectric transducer-controlled dual-mode switchable bandpass filter is introduced. A piezoelectric transducer is used to lift up or pull down the attached dielectric substrate perturbation. When the dielectric substrate is pulled down, the perturbation excites dual modes and the dual-mode filter is on. The return loss is better than 10 dB and the insertion loss is less than 3 dB from 2.92 to 3 GHz. When the dielectric substrate is lifted up, the dual-mode resonator is unperturbed and the dual-mode filter is off. The isolation is 21 dB at 3 GHz. The on-off ratio is 18 dB.