Multibeam antennas have found more and more applications in current and future communication systems. In this letter, a low-profile multibeam fully planar folded transmitarray antenna (FTA) based on the bifocal principle is proposed. It consists of a reflectarray, a transmitarray, and a group of identical planar feeding antennas. The transmitarray is developed with the metasurface and achieves high transmission efficiency and 3 b compensation phases. A new technique is proposed to improve the isolations among the feeding antennas by taking advantage of the multiplicity of the feeding elements. As an example, a multibeam FTA operating at the Ku-band was designed, fabricated, and tested. Experimental results achieve a peak gain of 22.7 dBi and a scanning range of ±21°, with a maximum feed isolation of 24 dB.

中文翻译：

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Ku波段的紧凑型多波束折叠式发射阵列天线

在当前和未来的通信系统中，多波束天线已发现越来越多的应用。在这封信中，提出了一种基于双焦点原理的薄型多波束全平面折叠发射阵列天线（FTA）。它由一个反射阵列，一个发射阵列和一组相同的平面馈电天线组成。发射阵列与超表面一起开发，并实现了高传输效率和3b补偿阶段。提出了一种新技术，通过利用多个馈电元件来改善馈电天线之间的隔离度。例如，设计，制造和测试了在Ku频段运行的多光束FTA。实验结果实现了22.7 dBi的峰值增益和±21°的扫描范围，最大馈电隔离度为24 dB。