High Selectivity Ultra-Wideband (UWB) Mutimode Stepped-Impedance Resonators (SIRs) Bandpass Filter with Two-Layer Broadside-Coupled Structure

Ultra-wideband (UWB) bandpass filter with high selectivity response is contrived on the multimode characteristic of stepped-impedance resonators (SIRs). To achieve strong coupling requirement, two-layer broadside-coupled structure is employed. Using three triple-mode SIRs, quasi-Chebyshev filter with nine transmission poles is synthesized with a fractional bandwidth (BW) Delta = 110%. Measured results of experimental circuits show good agreement with simulated responses.