Dual-Band Substrate Integrated Waveguide Filter With Independent TE₁₀₁ and TE₁₀₂ Coupling

This article presents a technique for dual-band substrate integrated waveguide (SIW) filters to implement independent coupling for their dual bands based on multilayers and overlapped cavities. It is achieved by using the proposed intercoupling slots in the middle layers. The slots parallel to and near the edge implement TE101 coupling, while the orthogonal slots in the center implement TE102 coupling, and they work independently of each other. Due to their independence, the design complexity of dual-band SIW filters could be significantly decreased, particularly for high-order applications, and the design flexibility could be significantly increased, allowing the use of additional techniques to produce distinct and high-performance responses. Five prototypes are provided, including those that additionally use cross coupling and spurious mode suppression to achieve significantly improved selectivity. The proposed technique should be efficient for developing high-performance dual-band SIW filters in microwave and wireless circuits and systems.