This article presents a method for analyzing the coupling between two adjacent substrate-integrated waveguides (SIWs) sharing a common row of metallic cylinders, which is based on the concept of equivalent circuit and wavenumber calculation. When the specific sizes of two adjacent SIWs are known, the scattering parameters of the shared common row of metallic cylinders can be derived, and the equivalent transmission line model of the SIW coupling structure is extracted. The even-and odd-mode wavenumbers in both transverse and propagating directions are calculated for this equivalent circuit. For an ideal forward-wave directional coupler, the transmission and coupling coefficient are then derived directly from the wavenumber and the length of the structure. Based on the proposed method, three SIW directional couplers with different coupling levels are designed and fabricated for verification. Good agreements between the calculated and simulated coupling parameters are observed. The proposed method provides a simple and accurate approach to estimate the coupling between two closely spaced SIWs sharing one common row of metallic cylinders and is expected to use for the design of millimeter-wave SIW-based circuits and systems.

中文翻译：

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基于等效传输线模型的相邻基片集成波导耦合分析

本文基于等效电路和波数计算的概念，提出了一种分析共用一排金属圆柱体的相邻衬底集成波导 (SIW) 之间耦合的方法。当已知两个相邻SIW的具体尺寸时，可以推导出共用金属圆柱排的散射参数，并提取SIW耦合结构的等效传输线模型。计算此等效电路的横向和传播方向的偶模和奇模波数。对于理想的前向波定向耦合器，传输和耦合系数可以直接从波数和结构长度导出。基于所提出的方法，设计和制造了三个具有不同耦合水平的 SIW 定向耦合器以进行验证。观察到计算的和模拟的耦合参数之间的良好一致性。所提出的方法提供了一种简单而准确的方法来估计共享一排公共金属圆柱体的两个紧密间隔的 SIW 之间的耦合，并有望用于基于毫米波 SIW 的电路和系统的设计。