Piezoelectric transducer tuned bandstop filter

A tunable bandstop filter with a wide tuning range is presented. A piezoelectric transducer with an attached dielectric perturber is used to perturb the filter to obtain a wide tuning range. Without changing the dimensions of the bandstop filter the tunable bandstop can provide a wide tuning range of 25% from 4.5 to 6 GHz. The high performance bandstop filter is useful for many microwave applications