Substrate integrated folded-waveguide cross-coupled filter with negative coupling structure

Abstract

This paper presents a multilayer cross-coupled substrate integrated folded-waveguide filter with pseudo-elliptic power transfer function. The bandpass filter which consists of four resonators has a central frequency of 28 GHz with a passband of 1000 MHz and exhibits adjacent channel selectivity of 25 dB. Design procedure is briefly explained, coupling matrix and coupling scheme are derived, and theoretical transfer function is built. Taking into account a loss correction, simulated results agree well with those obtained theoretically