Abstract Achieving simultaneous controls of the amplitude and phase for electromagnetic waves is essential when shaping a complete wave-front aimed at forming an arbitrary beam. Here a strategy of manipulating the reflected amplitude and phase is proposed using a bi-layered metasurface element. The metasurface unit cell, consisting of a modified I-shape particle and one all-metal ground, achieves broadband phase- and amplitude control by tuning the gap size and rotating the modified I-shape particle, respectively. As a proof of concept, we design a fan-shaped beam metasurface antenna using the genetic algorithm to obtain the optimal phase and amplitude distributions. A Vivaldi antenna with less blockage effect is chosen to illuminate the metasurface, and then the amplitude and phase are compensated by the elements to achieve the optimized distributions. Finally, the beam-forming metasurface antenna is simulated, fabricated, and measured. The results show that the metasurface can generate a flat top beam under rectangular coordinate within the frequency range of 9–12 GHz. Our findings not only provide a universal way for generating beams with arbitrary shapes using metasurfaces but also offer an economical and simple alternative for a beam-forming array antenna.

中文翻译：

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具有同步相位和幅度调制的宽带波束形成超表面

摘要 在形成一个完整的波前以形成任意波束时，实现电磁波的幅度和相位的同时控制是必不可少的。这里提出了一种使用双层超表面元素来操纵反射幅度和相位的策略。超表面晶胞由改良的 I 形粒子和一个全金属接地组成，分别通过调整间隙大小和旋转改良的 I 形粒子来实现宽带相位和幅度控制。作为概念证明，我们使用遗传算法设计了扇形波束超表面天线以获得最佳相位和幅度分布。选择阻塞效应较小的 Vivaldi 天线来照亮超表面，然后通过元件补偿幅度和相位以实现优化的分布。最后，对波束成形超表面天线进行了仿真、制造和测量。结果表明，超表面可以在9-12 GHz频率范围内在直角坐标下产生平顶光束。我们的发现不仅提供了一种使用超表面生成具有任意形状的波束的通用方法，而且还为波束成形阵列天线提供了一种经济且简单的替代方案。