A study on beam-tilt type planar antenna having high aperture efficiency.

在大规模多单元平面阵的构建中，减小馈电损耗对于实现高效率性能是重要的。本文提出了一种通过低损耗径向波导激励单馈圆极化微带天线（CP-MSA）的波束倾斜型平面天线。为了检验这种天线的性能，我们在SHF波段制作了几种倾斜波束型平面阵列天线，并进行了测试，得到了如下结果。阵列的轴比在很宽的频带范围内被抑制到1.0 dB以下。由径向线的内径确定的孔径效率η在SHF波段达到约90%。在检查输入阻抗特性时，测试阵列的VSWR在宽带区域上低于1.5。如前所述，由径向线馈电的这种平面阵列表现出高效率性能（约90%孔径效率）。证明了这种天线可以作为圆极化平面天线的一种实用模型。

In construction of a large-scale multi-element planar array, reduction of the feeding loss is important for realization of high-efficiency performance. In reflection of this requirement, much attention is paid to a planar antenna having a loss-suppressed feeding system.This work presents a beam-tilt type planar antenna which excites singly-fed circularly polarized microstrip antenna (CP-MSA) via a low-loss radial waveguide. In order to check the performance of this antenna, some beam-tilt type planar arrays were fabricated and tested at the SHF-band.As a result of experiment, the following results were obtained. The axial ratio of the array was suppressed to below 1.0 dB over a wide range of frequency band. The aperture efficiency eta as determined from the inner diameter of the radial line reached approximately 90% at the SHF-band.On examining the input impedance characteristics, VSWR of a test array was below 1.5 over a broadband region.As mentioned previously, this planar array fed by a radial line demonstrated high-efficiency performance (approximately 90% aperture efficiency). It was conformed that this type of antenna can be useful model of a circularly polarized planar antenna.