In this study, high common-mode (CM) suppression balanced substrate-integrated waveguide (SIW) bandpass filter (BPF) and half-mode SIW (HMSIW) directional coupler are formed by two vertically stacked identical SIW or HMSIW single-ended ones and an aperture etched on the common ground between them. Under CM operation, the aperture is perfect magnetic conductor (PMC). When the height is less than λ _g /4, the space between perfect electric conductor and PMC cannot transmit electromagnetic wave and a total reflection is got at the aperture edge. So, the aperture structure in SIW can effectively cut off CM noise over a wide frequency range. For the HMSIW, the spoof surface plasmon polariton structure is further loaded in the aperture near the open circuit plane to suppress the slot line mode (main TE mode). The CM suppression can be basically made independent of differential-mode response, which is very important to simplify the design and tuning processes. Finally, high CM suppression balanced SIW BPF and HMSIW directional coupler are designed and fabricated. Good agreements between the simulated and measured results demonstrate the validity of proposed configurations.

中文翻译：

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高CM抑制平衡SIW BPF和HMSIW定向耦合器，具有完美的电导体/完美磁导体特性

在这项研究中，高共模（CM）抑制平衡的基片集成波导（SIW）带通滤波器（BPF）和半模SIW（HMSIW）定向耦合器是由两个垂直堆叠的相同SIW或HMSIW单端滤波器构成的，在它们之间的共同点上刻有一个孔。在CM模式下，光圈是完美的磁导体（PMC）。当高度小于λ _g / 4时，理想电导体与PMC之间的空间无法传输电磁波，并且在光阑边缘会产生全反射。因此，SIW中的孔径结构可以有效地在很宽的频率范围内消除CM噪声。对于HMSIW，欺骗表面等离子体激元极化子结构进一步加载在开路平面附近的孔中，以抑制缝隙线模式（主TE模式）。CM抑制基本上可以独立于差模响应进行，这对于简化设计和调谐过程非常重要。最后，设计并制造了高共模抑制平衡的SIW BPF和HMSIW定向耦合器。模拟结果和测量结果之间的良好一致性证明了所提出配置的有效性。