This paper discusses the design of a high gain right-hand circularly polarized millimeter-wave frequency reconfigurable antenna array. The 16-element antenna array is designed to reconfigure its operating frequency over both K- and Ka-bands. More specifically, the reconfigurability is ensured through the integration of a modified ring resonator along with the array’s sequentially rotated stacked feeding network. The ring resonator is designed to reconfigure its operating frequency over four distinct bands with center frequencies at 25 GHz, 26 GHz, 27.75 GHz and 29 GHz, respectively. Such integration enables the proposed millimeter-wave antenna array to exhibit unique radiation characteristics by maintaining circular polarization with an Axial Ratio (AR) < 1 dB in a fractional bandwidth of 37.5% between 21.2 GHz and 31 GHz. A Figure of Merit that takes into account the array’s axial ratio, sidelobe levels and fractional bandwidth is developed to highlight the unique performance of the presented millimeter-wave circularly polarized array in comparison to available work in the literature. The fabricated antenna array shows good agreement with the simulated data where it is found that the measured realized gain exceeds 12 dBic with sidelobe levels of less than −17.5 dB over the various frequency bands of the frequency reconfigurable antenna array.

中文翻译：

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毫米波频率可重构圆极化天线阵列

本文讨论了一种高增益右旋圆极化毫米波频率可重构天线阵列的设计。16 单元天线阵列旨在重新配置其在 K 和 Ka 波段上的工作频率。更具体地说，通过将改进的环形谐振器与阵列顺序旋转的堆叠馈电网络集成在一起，确保了可重构性。环形谐振器旨在在四个不同频段上重新配置其工作频率，中心频率分别为 25 GHz、26 GHz、27.75 GHz 和 29 GHz。这种集成使提议的毫米波天线阵列能够​​通过在 21.2 GHz 和 31 GHz 之间的 37.5% 的部分带宽中保持轴向比 (AR) < 1 dB 的圆极化来展现独特的辐射特性。开发了一个考虑阵列轴比、旁瓣电平和分数带宽的品质因数，以突出所呈现的毫米波圆极化阵列与文献中的可用工作相比的独特性能。制造的天线阵列与模拟数据显示出良好的一致性，其中发现实测增益超过 12 dBic，旁瓣电平在频率可重构天线阵列的各个频段上小于 -17.5 dB。