In this article, two Ka‐band (26.5‐40 GHz) waveguide attenuators designed for three‐dimensional (3‐D) metal printing are presented. These designs are based on long waveguides with elliptical cross‐sections, so that the waveguide structure can be self‐supported during printing. Bended waveguide and helical waveguide are utilized by the two attenuators, respectively, to achieve reduced overall sizes. The attenuations are fixed, however, these can be altered by varying the length/height of waveguides. The limitation of 3‐D metal printing process on surface roughness is also used to provide attenuation. Therefore, the proposed attenuators can cope with printing process with relatively poor surface finish. The prototype designs are fabricated using a metallic selective laser melting (SLM) process and are measured to have good electrical performance across the full waveguide band. The measured attenuation values are in the range of 3.7 to 6.3 dB for the bended waveguide attenuator and 4.3 to 6.3 dB for the helical waveguide attenuator. Both attenuators are measured to have a good return loss (S₁₁ < −20 dB) across the whole Ka‐band. This demonstrates that 3‐D metal printed attenuators could be an attractive alternative to the conventional designs based on absorbing materials, particularly for applications demanding high powers.

中文翻译：

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在ka频段（26.5-40 GHz）下运行的3D打印波导衰减器

本文介绍了两个专为三维（3D）金属印刷设计的Ka波段（26.5-40 GHz）波导衰减器。这些设计基于具有椭圆形横截面的长波导，因此在打印过程中可以自支撑波导结构。两个衰减器分别利用弯曲的波导和螺旋形波导来减小整体尺寸。衰减是固定的，但是可以通过更改波导的长度/高度来更改衰减。3D金属印刷工艺对表面粗糙度的限制还用于提供衰减。因此，所提出的衰减器可以应付表面光洁度较差的印刷过程。原型设计是使用金属选择性激光熔化（SLM）工艺制造的，并经过测量在整个波导带上均具有良好的电性能。弯曲波导衰减器的测量衰减值在3.7至6.3 dB范围内，螺旋波导衰减器的测量衰减值在4.3至6.3 dB范围内。测量两个衰减器的回波损耗（S在整个Ka频带上为₁₁ <−20 dB）。这表明3D金属印刷衰减器可能是基于吸收材料的传统设计的有吸引力的替代品，特别是对于要求高功率的应用。