Multilayer Dual-band Filter Based on Substrate Integrated Waveguide (SIW)

This letter presents a dual-layered filter with dual band using mixed dual-mode and single-mode resonators. An example of a substrate integrated folded waveguide (SIFW) with two channel and each channel of two single-mode (TE101 and TE201) is demonstrated using substrate integrated waveguide technology. A type of microstrip line to CPW coplanar transition as passive input feed structure is inserted between source and load. Compared to conventional waveguides, the structure of folded waveguides roughly shrinks half. Furthermore, the fractional bandwidths (FBWs) of the two channel filters can be allocated flexibly based on the FBW design graph. A prototype centered at 11.82GHz and 13.51GHz with respective FBWs of 5.3% and 5.5% is designed for demonstration.