Terahertz technology is a hotspot in the current academic research. In this study, a 400 GHz broadband multi-branch waveguide hybrid coupler is designed, but it is very difficult to fabricate. In order to release the processing difficulty, a modified five-branch hybrid coupler has also been designed, fabricated and measured. The hybrid coupler consists of five modified branches and has been optimised to a great performance, which increases the operation bandwidth. Compared to the traditional five-branch hybrid coupler design, this structure has a wider operation bandwidth and the bandwidth is almost the same as traditional seven-branch hybrid coupler. Based on this model, the performance of the coupler is optimised by HFSS software. The measurement results show good performance that >18 dB return loss ( S ₁₁ ) and isolation ( S ₂₃ ), 90° ± 2° phase difference and 0.3 dB amplitude imbalance are obtained in the frequency range of 380–460 GHz, agreeing well with the simulation results.

中文翻译：

---

四百兆赫兹宽带多分支波导耦合器

太赫兹技术是当前学术研究的热点。在这项研究中，设计了一个400 GHz宽带多分支波导混合耦合器，但是很难制造。为了消除加工困难，还设计，制造和测量了改进的五分支混合耦合器。混合耦合器由五个修改的分支组成，并且已经过优化以实现出色的性能，从而增加了操作带宽。与传统的五分支混合耦合器设计相比，该结构具有更宽的工作带宽，带宽几乎与传统的七分支混合耦合器相同。基于此模型，可通过HFSS软件优化耦合器的性能。测量结果表明，回波损耗> 18 dB（ 小号 ₁₁ ）和隔离（ 小号 ₂₃ ），在380–460 GHz的频率范围内获得90°±2°的相位差和0.3 dB的幅度失衡，与仿真结果非常吻合。