A wideband millimeter-wave (mmW) circular aperture horn antenna with a conical radiation pattern realized by the metallic three-dimensional (3-D) printing technology is presented in this letter. The proposed structure consists of a coaxial waveguide and a quadruple-ridged conical horn. The horn antenna is fabricated using a direct metal laser sintering (DMLS) technology, and both manual polishing and yellow-gold coating are employed to realize a surface roughness of Ra = 1.6161 μm. The overall size of the fabricated antenna is 20 mm × 20 mm × 15.8 mm. Experimental measurements show that a wide relative impedance bandwidth of 60.7% and a peak gain of 11.4 dBi can be achieved within the frequency band of 24.9–46.6 GHz.

中文翻译：

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具有锥形辐射模式的 3D 打印宽带毫米波喇叭天线

这封信介绍了一种采用金属三维 (3-D) 打印技术实现的锥形辐射图的宽带毫米波 (mmW) 圆形孔径喇叭天线。所提出的结构由同轴波导和四脊锥形喇叭组成。喇叭天线采用直接金属激光烧结（DMLS）技术制造，并采用手工抛光和黄金涂层，实现表面粗糙度 Ra = 1.6161 μm。制成的天线的整体尺寸为 20 mm × 20 mm × 15.8 mm。实验测量表明，在 24.9-46.6 GHz 频带内可以实现 60.7% 的宽相对阻抗带宽和 11.4 dBi 的峰值增益。