Novel bandpass filter and balun based on the double-sided parallel-strip lines (DSPSL)

Abstract

With the rapid growth of wireless and mobile communications, multi-layer structure has become a hot research topic in the microwave component design for size reduction and performance improvements. In this project, a novel three layer dual-band bandpass filter design with good return loss and low insertion loss was investigated based on the double sided parallel strip lines (DSPSL) with an inserted conductor plane The conductor plane is inserted into the middle of substrate, and can be treated as a “ RF ground” to isolate the top and bottom circuits With the non-identical structures on the top and bottom layer, the filter provide two different transmission paths between two layers and hence provide a dual-band bandpass effect. Moreover, a novel three-layer balun with band pass response is further investigated based on this structure.