A Microstrip Planar UWB Bandpass Filter with Dual Notched Bands using Dual-mode resonator

This research proposes a novel highly selective E-shape resonator-based ultra-wideband (UWB) bandpass filter (BPF), which can generate dual adjustable notches. Initially, a UWB filter with a frequency range of 2.8 GHz to 10.9 GHz is developed using a triple-mode resonator that has been short-circuited, two
$\lambda/2$
wavelength open-circuited radial stubs that have to generate transmission zeros (TZs), and then coupled E-shape resonators above three-line parallel coupling line of the filter to generate notches to suppress narrowband signal interference at 5.8 GHz and 8 GHz. The proposed filter can be implemented for stopband frequencies centered at 5.75 GHz and 7.95 GHz, and they correspond to notch magnitudes of −39 dB and −29 dB. Finally, the notch-generating resonator is flexible to be embedded in the UWB filter, and it does not increase the circuit area of the proposed filter. The consistency of the simulation and experimental results illustrates that a highly selective and compact UWB BPF with dual notches has been achieved.