A Quarter-Wavelength Wideband Bandpass Filter with Two notch Bands

In this paper, a wideband bandpass filter (WD BPF) with two notch bands is presented. The proposed filter is started from a terminated cross-shaped resonator (TCSR), which is fully composed of quarter-wavelength transmission lines. Then, a pair of quarter-wavelength parallel-coupled lines (PCLs) are added. With the aid of the added parts, a WB BPF with two notch bands can be realized. To verify this, a prototype filter is designed and experimentally measured. The experimental results are in good agree well with the theoretical analysis and therefore validate a simple designing approach of WB BPFs with two notch bands.