Tunable notched planar bandpass filter for ultra wideband applications

This paper proposes a compact and tunable notch ultrawide band bandpass filter. We used the interdigital resonator for designing this filter. Using interdigital finger resonator we are getting the ultrawide band with one notch and due to diode we are getting the second notch. When diode is in OFF state we are getting one notch at 7.75GHz and in ON state we are getting the two notches one the previous one and second at 4.5GHz. The notches are removing the interference due to satellite systems in UWB band. The size of filter is compact with dimension 17 × 17 X 1 mm3 with the ground plane. For designing of this structure FR-4 substrate of thickness 1 mm and dielectric constant 4.9 is used. Simulation and analysis of this structure is done on the electromagnetic simulation software, computer simulation technology microwave studio (CST MWS). The proposed filter is working for whole UWB band from 3.1 to 10.6GHz and rejecting the frequencies 4.5GHz and 7.75GHz. The insertion loss of first notch band is -17dB and and for second notched band insertion loss is -14dB.