Cross-coupled substrate integrated waveguide filter with enhanced electric coupling

This paper presents an electric coupling structure based on double-layered SIW cavity resonators which provides enhanced coupling coefficient. Electric coupling is achieved by inserting two short-ended striplines between two SIW cavities. The electric coupling depends on the width of the stripline. The proposed structure can achieve coupling coefficient more than 0.12. In order to validate the proposed structure, a fourth-order cross-coupled filter having center frequency of 9.7 GHz and 3-dB bandwidth of 13% has been designed.