This paper presents single and dual notch ultra-wideband bandpass filters (UWB BPFs) to mitigate interference with coexisting wireless communication systems in ultra-wideband (UWB). The single and dual notch UWB BPF is developed by using signal interaction concept loaded with stub loaded resonator. The stub loaded resonator creates notches in the passband to avoid the interference with coexisting wireless communication systems. The notch frequency can be placed at the points of interest within passband by selecting a proper length of stub loaded resonator. Transmission zeros are introduced to enhance the selectivity of stopband. It presents UWB BPF with single notch at the frequency of 6.5 GHz and dual notch at the frequencies of 6.3 GHz and 8.0 GHz. The circuit size of proposed filters is 6 mm x 6 mm and 6 mm x 6 mm. The proposed filters exhibit good performance in terms of compact size, good fractional bandwidth and sharp selectivity. All the filters are simulated and fabricated on a Rogers R03010 substrate with relative permittivity of 10.2 and thickness of 1.28 mm. There is good agreement between simulated and measured results.
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