Compact Silicon-Micromachined Wideband 220-330-GHz Turnstile Orthomode Transducer
Compact Silicon-Micromachined Wideband 220-330-GHz Turnstile Orthomode Transducer
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DOI：
10.1109/tthz.2018.2882745
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发表时间：
2019-01-01
影响因子：
3.2
通讯作者：
Oberhammer, Joachim
中科院分区：
文献类型：
--
作者：
Gomez-Torrent, Adrian;Shah, Umer;Oberhammer, Joachim
本文报道了一种在220-330-GHz频段用硅微机械加工实现的旋转栅结正交模换能器（OMT）。旋转栅门OMT是非常宽带的，并且允许共面端口，但是需要精确且复杂的几何形状，这使得它们的制造在较高频率下具有挑战性。本文介绍的紧凑型10 mm x 10 mm x 0.9 mm OMT芯片是第一个在任何频率范围内的微机械全频带OMT，也是第二个在110 GHz以上实现的旋转门OMT。在220-330-GHz频带中，在整个波导频带上测得的插入损耗（平均0.3 dB，最坏情况0.6 dB）和交叉极化（平均60 dB，最坏情况30 dB）代表了任何宽带OMT的最佳性能，而不管设计或制造技术如何。平均回波损耗为22 dB（最坏情况为16 dB），与以前的作品相当或更好。本文讨论了这种复杂的9层硅微机械器件的设计考虑和妥协，包括侧壁斜率的影响，钻蚀，和芯片之间的键合后未对准。结果表明，对于一个设备，是非常敏感的几何变化，如旋转栅门OMT，它是必要的，以预期和补偿任何制造缺陷的设计，以实现高RF性能。
This paper reports on a turnstile-junction orthomode transducer (OMT) implemented by silicon micromachining in the 220-330-GHz band. Turnstile OMTs are very wideband and allow for co-planar ports but require accurate and complex geometries, which makes their fabrication challenging at higher frequencies. The compact 10 mm x 10 mm x 0.9 mm OMT-chip presented in this paper is the first micromachined full-band OMT in any frequency range and only the second turnstile OMT implemented above 110 GHz. The measured insertion loss (0.3 dB average, 0.6 dB worst case) and the cross polarization (60 dB average, 30 dB worst case) over the whole waveguide band represent the best performance of any wideband OMT, regardless of design or fabrication technology, in the 220-330-GHz band. The return loss with 22 dB average (16 dB worst case) is comparable with or better than previous works. This paper discusses design considerations and compromises of this complex 9-layer silicon micromachined device, including the influence of side-wall slopes, underetching, and postbonding misalignment between the chips. It is shown that for a device that is very sensitive to geometrical variations, such as a turnstile OMT, it is necessary to anticipate and compensate for any fabrication imperfections in the design to achieve high RF performance.