An influence on radiation characteristics by FSS on a beam-waveguide feed with FSS
An influence on radiation characteristics by FSS on a beam-waveguide feed with FSS
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FSS 对带有 FSS 的光束波导馈电的辐射特性的影响
DOI：
10.1002/ecja.10041
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
S. Urasaki
中科院分区：
文献类型：
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作者：
N. Miyahara;T. Mizuno;S. Matsumoto;H. Deguchi;S. Urasaki
用波束波导馈电的双反射器天线广泛用于卫星通信基站和射电天文学。当天线在多个频率下使用时，利用波束波导中的频率选择表面(FSS)进行双工是有效的。传统上，当设计反射器表面包含FSS的天线或评估其辐射特性时，假设FSS是理想的，并通过金属板或透明板对其进行建模，以便推导天线在FSS用于传输或反射的频率范围内的辐射特性。接下来，单独导出 FSS 的回波损耗或传输损耗。这种损耗被认为是具有理想FSS的天线的辐射特性的增益降低。然而，由于FSS的反射和透射特性根据入射到FSS上的波的入射角和偏振角而不同，所以整个天线系统的辐射图以及入射到连接到FSS的聚焦反射器上的波的辐射图与使用由理想FSS建模的聚焦反射器时获得的辐射图不同。因此，为了准确设计和评估使用FSS的波束波导馈电的双反射器天线，除了FSS引起的损耗之外，还必须考虑FSS的反射和传输特性对辐射特性的影响。本文研究了当由部分安装了FSS的光束波导馈电的双反射器被主辐射器的基模（EH11）激励时，FSS对辐射特性的影响。为了计算束波导馈源中的电磁场，采用束模展开法，从而考虑波动效应。为了计算FSS的反射和传输特性，使用了一种简单的方法，其中将FSS散射的电磁场以Floquet模式展开，并通过矩量法确定FSS上的电场。此外，为了减少金属部分和FSS处的反射相位差对辐射特性的影响，FSS的安装位置被偏移，从而补偿来自两个区域的反射波的相位差。发现所提出的方法是有效的。 © 2003 Wiley periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 21–31, 2003；在线发表于 Wiley InterScience (www.interscience.wiley.com)。 DOI 10.1002/ecja.10041
Dual reflector antennas fed with a beam waveguide are widely used for base stations of satellite communication and for radio astronomy. When the antenna is used at several frequencies, it is effective to carry out diplexing with a frequency selective surface (FSS) in the beam waveguide. Traditionally, when an antenna containing an FSS on the reflector surface is designed, or its radiation characteristics are evaluated, it is assumed that the FSS is ideal and it is modeled by a metal plate or a transparent plate in order to derive the radiation characteristics of the antenna at the frequency range in which the FSS is used for transmission or reflection. Next, the return loss or transmission loss of the FSS alone is derived. This loss has been considered as gain reduction of the radiation characteristics of the antenna with an ideal FSS. However, since the reflection and transmission characteristics of the FSS differ depending on the angle of incidence and polarization angle of the wave incident on the FSS, the radiation pattern of the entire antenna system and that of the wave that is incident on the focusing reflector connected to the FSS are different from those obtained when using a focusing reflector modeled by an ideal FSS. Hence, for accurate design and evaluation of a dual reflector antenna fed by a beam waveguide using an FSS, the effect of the reflection and transmission characteristics of the FSS on the radiation characteristics must be considered in addition to the loss caused by the FSS. This paper studies the effect of the FSS on the radiation characteristics when a dual reflector fed by a beam waveguide with an FSS partially installed is excited by the fundamental mode (EH11) of the primary radiator. For calculation of the electromagnetic field in the beam-waveguide feed, the beam mode expansion method is used, so that the wave effect is taken into account. For calculation of the reflection and transmission characteristics of the FSS, a simple method is used in which the electromagnetic field scattered by the FSS is expanded in terms of Floquet modes and the electric field on the FSS is determined by the method of moments. Further, in order to reduce the effect on the radiation characteristics resulting from the difference in reflection phase at the metal part and at the FSS, the location of installation of the FSS is offset so that the phase difference of the reflected waves from two regions is compensated. This proposed method is found effective. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(5): 21–31, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10041