A Slow Wave Ridged Half-Mode Substrate Integrated Waveguide With Spoof Surface Plasmon Polaritons

In this article, a slow wave (SW) ridged half-mode substrate integrated waveguide (RHMSIW) combined with spoof surface plasmon polaritons (SSPPs) structure is proposed. The SW feature is achieved by integrating the SSPP structure into the metal ridge of RHMSIW. Besides, the proposed structure has a compact lateral size because the ridge of the RHMSIW introduces a step capacitance in the waveguide. Due to the loading of the SSPP structure, the proposed RHMSIW-SSPP structure has the ability of strong electric field confinement. Compared with the RHMSIW structure, the proposed RHMSIW-SSPP structure has a low crosstalk feature. A prototype of the proposed RHMSIW-SSPP structure with band-pass 4.5-14 GHz is designed and fabricated under PCB process. The proposed RHMSIW-SSPP structure reduces the longitudinal size over 50% and the lateral width by 40% compared with the HMSIW, and reduces the longitudinal size over 50% and the transverse width by 70% compared with the SIW. Therefore, the proposed structure has potential applications in miniaturized microwave and RF systems.