Tunable bandpass microwave filters based on defect commandable photonic bandgap waveguides

A new type of tunable filter based on a commandable defect in the bandgap of a periodic CPW structure is proposed. The defect level is tuned either mechanically by adding a covering slab over the device or electrically by polarising diodes located at the defect. The validity of this concept is experimentally demonstrated at 4 GHz. This kind of filter is well suited for applications in the 10 to 60 GHz frequency range.