Design of UWB bandpass filter with dual notched bands based on E-shaped resonator

A new microstrip ultra-wideband (UWB) bandpass filter (BPF) with dual sharply rejected notched bands based on E-shaped resonator is proposed in this letter. The basic UWB BPF is designed using interdigital coupled lines and rectangular patch multiple-mode resonator (MMR). Then, the resonance properties of the E-shaped resonator are studied. The analyzed results reveal that the dual-mode resonant property of the E-shaped resonator can be utilized in the UWB BPF design to achieve dual band-notched characteristics. To validate the design theory, a microstrip UWB BPF with two notch-bands centered at the frequencies of 5.8 GHz and 8.0 GHz, respectively, is designed and fabricated. Both simulation and experimental results are provided with good agreement.