A new approach for the design of wideband band-pass filters with extended stop-bands

In this paper, a new design approach is introduced for the design of very wideband band-pass filters with extended stop-bands. The approach is based on interleaving two low-pass filter sections with a high-pass filter section. The proposed approach is applied to the realization of a wideband filter in the frequency range from 0.8 GHz to 2.2 GHz. Open circuit stubs from the low-pass filter sections are used to realize finite stop-band transmission zeros. The filter is analyzed using circuit model and the results were verified using full electromagnetic simulations as well as actual measurements. The simulations and measurements show that the proposed design approach results in a wideband filter with very low insertion loss in the pass-band and a very wide stop-band with stop-band rejection of 25 dB or more.