The growing popularity of metasurfaces and their exceptional physical phenomena has gained remarkable interest in terms of propagation and electromagnetic wave control. Particularly, for the case of retroreflection, retrodirective gradient metasurfaces are well known for their reciprocal responses in terms of retroreflection specially for subwavelength super-cell periodicity designs. Recently, we have observed that for metasurfaces with high super-cell periodicities greater than $$2\lambda $$ 2 λ , the retrodirective metasurface loses its reciprocal response in terms of retrodirectivity. The main challenge in this case is to retain the reciprocal response, as well as achieving efficient responses for retroreflection at the higher orders of diffraction that exist at these periodicities. Thus, in this paper we demonstrate the design of a retrodirective metasurface from non-reciprocal to reciprocal following the generalized phase law of reflection and introducing the impedance modulation technique, for a metasurface operating at 14.7 GHz with a super-cell periodicity of $$2.88 \lambda $$ 2.88 λ . On the other hand, with a well-engineered surface impedance of a super-cell at these periodicities, efficient responses of retroreflection can be achieved at the higher orders of diffraction, giving rise to a retrodirective metasurface design operating simultaneously for multiple incident angles. Retroreflection has been achieved at eleven angles simultaneously, and the reciprocal property was retained at the desired angle of incidence $$10^{\circ }$$ 10 ∘ .

中文翻译：

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使用阻抗调制从非互易到互易的逆向超表面用于高超级单元周期设计

超表面的日益普及及其特殊的物理现象在传播和电磁波控制方面引起了人们极大的兴趣。特别是，对于回射的情况，回射梯度超表面因其在回射方面的互反响应而闻名，特别是对于亚波长超级单元周期性设计。最近，我们观察到，对于具有大于 $$2\lambda $$2 λ 的高超级单元周期的超表面，逆向超表面在逆向性方面失去了其相互响应。在这种情况下的主要挑战是保留互易响应，以及在这些周期性存在的更高衍射级处实现回射的有效响应。因此，在本文中，我们展示了从非互易到互易的逆向超表面的设计，遵循广义的反射相位定律并引入阻抗调制技术，用于在 14.7 GHz 下工作且超级单元周期为 2.88 美元的超表面2.88 美元 另一方面，在这些周期性的超级电池的表面阻抗设计良好的情况下，可以在更高的衍射级上实现有效的回射响应，从而产生对多个入射角同时操作的回向超表面设计。已经在 11 个角度同时实现了逆向反射，并且在所需的入射角 $$10^{\circ }$$ 10 ∘ 保留了互易特性。