In this letter, a novel waveguide-to-microstrip vertical transition using a bifurcated probe is presented. The bifurcated probe consists of a pair of thin parallel $E$ -plane probes and bend branches, which forms a strong current crowding effect for electromagnetic energy coupling from rectangular waveguide and broadband impendence matching. Therefore, the bifurcated probe can effectively reduce the sensitivity of probe dimensions to transition performance and design difficulty. To demonstrate this concept, a back-to-back bifurcated probe transition operating at WR-4.3 band (170–260 GHz) was fabricated and measured. Measured results show the double transition covers the entire WR-4.3 band with a minimum return loss (RL) of 16 dB and an average insertion loss (IL) of 0.84 dB, respectively.

中文翻译：

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使用分叉探头的毫米波宽带波导到微带过渡

在这封信中，提出了一种使用分叉探头的新型波导到微带的垂直过渡。分叉探头由一对细平行 $E$ 平面探针和弯曲分支，对矩形波导和宽带阻抗匹配的电磁能量耦合形成强电流聚集效应。因此，分叉探头可以有效降低探头尺寸对过渡性能和设计难度的敏感性。为了证明这一概念，我们制作并测量了在 WR-4.3 频段（170-260 GHz）下运行的背靠背分叉探头转换。测量结果表明，双转换覆盖了整个 WR-4.3 频段，最小回波损耗 (RL) 为 16 dB，平均插入损耗 (IL) 分别为 0.84 dB。