A low-profile dual-band shorted patch antenna (SPA) with bandwidth-enhancement and multifunctional beams is proposed in this article. Initially, the radiation patterns of the traditional SPA are extensively studied. It demonstrates that the radiated fields of its TM_1/2,0, TM_3/2,0, and TM_3/2,1 modes are unsuitable to be employed for multibeam radiation. As such, a pair of shorting pins2 is loaded underneath the radiating patch, aiming to transform the broadside-beam of TM_1/2,0 mode into the dual-beam. After that, a set of shorting pins3 is placed to reshape radiated fields of its TM_3/2,0 and TM_3/2,1 modes as the dual-beam and broadside-beam, respectively. Meanwhile, the resonant frequencies of its TM_1/2,0 and TM_1/2,1 modes are reallocated closely to that of TM_3/2,0 and TM_3/2,1 modes. With these arrangements, both of impedance bandwidth and radiation beams are enhanced under quadruple-mode resonance. Finally, the proposed SPA is fabricated and measured. The results illustrate that the microstrip patch antenna has successfully obtained an enhanced-bandwidth (|S₁₁< −10 dB) ranging from 4.0 to 4.29 GHz and 5.24 to 5.77 GHz with two in-band attenuation poles. Besides, a small thickness of about 0.04 free-space wavelength is still maintained, while keeping single-layer and single-fed properties. Most importantly, the proposed SPA has generated desired broadside−/dual-beam radiation patterns over the operating bands.

中文翻译：

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一种在整形模式下具有增强带宽和多功能波束的低剖面双频短路贴片天线

本文提出了一种具有带宽增强和多功能波束的低剖面双频短路贴片天线 (SPA)。最初，广泛研究了传统 SPA 的辐射模式。它表明其 TM _1/2,0、TM _3/2,0和 TM _3/2,1模式的辐射场不适用于多波束辐射。因此，在辐射贴片下方加载了一对短路销2，旨在将TM _1/2,0模式的宽边光束转换为双光束。之后，放置一组短路引脚₃以重塑其 TM _3/2,0和 TM _{3/2,1 的}辐射场模式分别为双光束和宽边光束。同时，其TM _1/2,0和TM _1/2,1模式的谐振频率重新分配为接近TM _3/2,0和TM _3/2,1模式的谐振频率。通过这些布置，阻抗带宽和辐射束在四模谐振下都得到了增强。最后，制造并测量了建议的 SPA。结果表明，微带贴片天线已成功获得增强的带宽（|S ₁₁< −10 dB) 范围为 4.0 至 4.29 GHz 和 5.24 至 5.77 GHz，具有两个带内衰减极点。此外，仍保持约0.04自由空间波长的小厚度，同时保持单层和单馈特性。最重要的是，提议的 SPA 已在工作频段上生成了所需的宽边/双波束辐射模式。