A quad-band filtering antenna based on a slotted half-mode substrate-integrated waveguide cavity is proposed. Three cavity edges are shorted by metallic posts and one edge is opened. Then three rectangular slots are etched to obtain multi-band operations and coaxial feeding is employed. Four radiation frequencies with similar field distributions but different resonating size can effectively radiate cavity energy through the opened edge and etched slots, resulting in good in-band antenna features. On the other hand, three radiation nulls whose dominant field is concentrated around the feeding port can generate little energy leakage, leading to good out-of-band filtering characteristics. The proposed design has been fabricated with an overall size of 0.40λ 0 × 0.20λ 0 . Measured radiation frequencies are at 3.35, 3.88, 4.54, and 5.18 GHz with high gain of about 5.0 dBi and efficiency of 70.0%, whereas measured radiation nulls are at 3.54, 4.24, and 4.91 GHz with very low gain of -16.75, -13.46, and -12.06 dBi and efficiencies of 0.59, 0.88, and 1.42%. Moreover, unidirectional patterns with stable radiation are experimentally confirmed.

中文翻译：

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基于开槽半模基片集成波导腔的四频滤波天线

提出了一种基于开槽半模基片集成波导腔的四频滤波天线。三个腔边缘由金属柱短路，一个边缘打开。然后蚀刻三个矩形槽以获得多频段操作，并采用同轴馈电。具有相似场分布但不同谐振尺寸的四个辐射频率可以通过开放的边缘和蚀刻的缝隙有效地辐射腔能量，从而产生良好的带内天线特性。另一方面，主导场集中在馈电端口周围的三个辐射零点可以产生很少的能量泄漏，从而导致良好的带外滤波特性。所提出的设计的总尺寸为 0.40λ 0 × 0.20λ 0 。测得的辐射频率为 3.35、3.88、4.54 和 5。18 GHz 具有约 5.0 dBi 的高增益和 70.0% 的效率，而测得的辐射零点位于 3.54、4.24 和 4.91 GHz，具有 -16.75、-13.46 和 -12.06 dBi 的极低增益以及 0.59、0.88 的效率和 1.42%。此外，实验证实了具有稳定辐射的单向模式。