We propose a waveguide directional coupler design with weak coupling using silicon-based suspended coupling microstrip probes and the split-block type of construction common in integrated millimeter wave components. WR4.0 coupler prototypes with standard UG-387 flanges were fabricated and measured. The simulation and measurement results show that this design achieves a coupling of around −18 dB, with a typical $\pm$2-dB variation across the band from 210 to 270 GHz, while the isolation is better than 30 dB. Tolerance studies confirm that this design could be scaled up to terahertz frequency with modern computer numerical control (CNC) machining and silicon chip fabrication technology.

中文翻译：

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用于太赫兹应用的基于硅芯片的波导定向耦合器

我们提出了一种具有弱耦合的波导定向耦合器设计，该设计使用基于硅的悬浮耦合微带探头和集成毫米波组件中常见的分块式结构。制造并测量了带有标准 UG-387 法兰的 WR4.0 耦合器原型。仿真和测量结果表明，该设计实现了约 -18 dB 的耦合，在 210 至 270 GHz 的频段内具有典型的 $\pm$2-dB 变化，而隔离度优于 30 dB。公差研究证实，这种设计可以通过现代计算机数控 (CNC) 加工和硅芯片制造技术放大到太赫兹频率。