An alternative Design Approach for the Design of Wideband Bandpass Filters Based on Cascaded Building Blocks

This paper introduces a novel design approach for the realization of wideband bandpass filters (BPFs). The technique is based on a conventional filter topology consisting of shunt short-circuited stubs connected by transmission lines where its λ_g/4 interconnecting lines and its λ_g/4 short-circuited stubs are replaced by a building block consisting of λ_g/8 lines separated by λ_g/8 short-circuited coupled-line sections. Guidelines on the design formulas through ABCD analysis in practical filter implementations are provided. Additionally, the manuscript presents a design example and its practical validation through the manufacturing and testing of a fourth-order microstrip-type BPF.