An UWB band pass filter with a notch band using stub loaded multi-mode resonator

In this paper a UWB band pass filter using multiple mode resonator (MMR) with a notch band is reported. The MMR is realized by loading an open stub at the center of a uniform impedance resonator. Two modes are located within UWB passband to achieve UWB band pass response. The resonator is coupled via input output feed line through interdigital coupled line with a high degree of coupling. In order to incorporate a notch band in UWB passband one arm of the interdigital coupled line is extended in outward direction. Out of phase cancellation model is implemented for notch band insertion at 6.8 GHz RFID frequency. The proposed UWB band pass filter is simulated and tuned to improve in band, out of band performance and also the notch characteristics.