This article presents the design and fabrication of low-loss, -weight, and -cost, modified Butler matrix in groove gap waveguide technology at W-band, implemented by additive manufacturing. The design, simulations, and measurements of each of the elements that conform to the modified Butler matrix are presented. The proposed modified Butler matrix is asymmetric and oriented to an easy assembly with a radial antenna in order to obtain simultaneous sum and difference patterns for a narrowband radar application. The measured individual components of the modified Butler matrix fit very well with the simulations. As for the full modified Butler matrix, measurements provide a 0.7% bandwidth below −20 dB for sum and difference ports centered at 94 GHz. The amplitude and phase imbalance are below 1.5 dB and 20°, respectively. This narrow bandwidth is due to the difference in length between input and output ports due to the asymmetry of the design. The total losses of the modified Butler matrix are below 1 dB.

中文翻译：

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用于单脉冲雷达的基于 W 波段间隙波导的 3D 打印修正巴特勒矩阵

本文介绍了 W 波段槽隙波导技术中低损耗、重量和成本的改进 Butler 矩阵的设计和制造，通过增材制造实现。介绍了符合修改后的巴特勒矩阵的每个元素的设计、模拟和测量。所提出的修正巴特勒矩阵是不对称的，并且易于与径向天线组装，以便为窄带雷达应用同时获得和和差方向图。修改后的巴特勒矩阵的测量单个分量与模拟非常吻合。对于完全修改的巴特勒矩阵，测量为以 94 GHz 为中心的和和差端口提供低于 -20 dB 的 0.7% 带宽。幅度和相位不平衡分别低于 1.5 dB 和 20°。这种窄带宽是由于设计的不对称导致的输入和输出端口之间的长度差异造成的。修改后的巴特勒矩阵的总损耗低于 1 dB。