Design Procedure of Continuous Profile Stopband Filters Implemented With Empty Substrate Integrated Coaxial Lines

This article presents a systematic procedure aimed to design continuous profile stopband filters assembled with empty substrate integrated coaxial lines. The coaxial filter is made of five low-cost substrate layers, where the central boards contain the filter profile. This structure exhibits unimodal TEM operation over a wide frequency band, it is not dispersive, it is shielded and cannot be interfered from external signals, and it can be easily...