A reflectarray antenna with an optimized sectorial beam is designed for the surveillance channel of a DVB-S-based passive radar (PR). The employment of satellite illuminators requires a high gain antenna to counteract the losses due to the great distance from the transmitter, but without forgetting a beamwidth wide enough to provide angular coverage. A method based on optimizing the position of several contiguous beams is proposed to achieve the required sectorial pattern. Different reflectarray elements are designed to achieve S-curves with smooth slopes and covering all the required phases (the S-curve represents the reflection phase of a single element, as a function of size, rotation and incidence angle). The real phase and modulus of the reflection coefficient of each element are considered in the optimization process to achieve the best real prototype. Geometry has been studied and adapted to employ commercial elements for the feed, feed-arm and the structure that holds the aperture. The designed prototype has been characterized in an anechoic chamber achieving a stable gain greater than 19 dBi in almost the complete DVB-S band, from $10.5$ GHz to 12 GHz with a sectorial beam of ${8.7}^{\circ }\times {5.2}^{\circ }$. The prototype has also been validated in PR trials in terrestrial scenarios allowing the detection of cars at distances up to 600 m away from the PR, improving the performance achieved with commercial parabolic dish antennas.

中文翻译：

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设计和验证具有优化波束的反射阵列天线，用于使用基于 DVB-S 的无源雷达监测地面目标

具有优化扇形波束的反射阵列天线专为基于 DVB-S 的无源雷达 (PR) 的监视信道而设计。卫星照明器的使用需要高增益天线来抵消由于距离发射器很远而造成的损失，但又不能忘记足够宽的波束宽度以提供角度覆盖。提出了一种基于优化几个连续波束位置的方法来实现所需的扇形图。不同的反射阵列元件被设计为实现具有平滑斜率并覆盖所有所需相位的 S 曲线（S 曲线代表单个元件的反射相位，作为尺寸、旋转和入射角的函数）。优化过程中考虑了各单元反射系数的真实相位和模量，以实现最佳真实原型。几何学已经被研究并适应于将商业元素用于进料、进料臂和保持孔的结构。设计的原型在一个消声室中进行了表征，在几乎整个 DVB-S 频段内实现了大于 19 dBi 的稳定增益，从$10.5$ GHz 至 12 GHz，扇形波束为 ${8.7}^{\circ }\times {5.2}^{\circ }$. 该原型还在地面场景中的 PR 试验中得到验证，允许检测距离 PR 最远 600 m 的汽车，从而提高商用抛物面天线的性能。