非对称十字孔双脊波导定向耦合器的设计

The Design of Double-Ridge Waveguide Directional Coupler with Unsymmetrical Cross Holes

借鉴波导定向耦合器的设计原理,采用双脊波导的形式(本文采用标准双脊波导WRD650型号)设计大功率宽频带定向耦合器。由于双脊波导相比于矩形波导,最低模式的截止频率更低,单模工作的频带更宽,特性阻抗更低,所以采用双脊波导的形式比矩形波导在带宽方面更有优势。波导耦合器耦合方式有很多种,最常用的有小孔耦合和缝隙耦合,本文采用非对称十字孔耦合的方式,并与等孔径分布和切比雪夫分布的圆孔耦合比较来确定非对称十字孔耦合方式,在耦合平坦度、方向性方面有更好的改进。利用电磁仿真软件进行仿真对比其结果,通过一些具体措施改善双脊波导定向耦合器的性能,使定向耦合器的各种设计指标达到要求。

Referring to the design principle waveguide directional coupler, we adopt the form of double-ridge waveguide to design high-power and broadband directional coupler （Type WRD650 standard double-ridge waveguide is used）. As we know that double-ridge waveguide has lower cut-off frequency, wider single mode bandwidth, and lower impedance compared with rectangular waveguide, using double-ridge form has superiority in bandwidth. Waveguide coupler has a lot of coupling means such as little holes and slots. In this article we adopt unsymmetrical cross hole coupling. Compared with cross hole and circular hole coupling it is found that the unsymmetrical cross hole coupling is better than circular hole in coupling flatness and directivity. Using electromagnetic simulation software the simulation results are compared. For achieving perfect target several particular actions to improve the performance of double-ridge waveguide coupler are taken.