相控阵-透镜系统的角信道容量与非局域波前工程
Angular-Channel Capacity and Nonlocal Wavefront Engineering for Phased-Array--Lens Systems
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto（多伦多大学爱德华·S·罗杰斯电气与计算机工程系）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
该研究建立相控阵-透镜系统高方向性波束扫描的角信道界限，提出利用非局域介质超透镜实现接近极限的波前工程，实验验证了保持50°扫描范围并提升2.5-3.5分贝方向性的紧凑圆柱形超透镜。
中文摘要 AI 辅助
具有高方向性的广角波束扫描从根本上受到衍射的限制，这制约了相控阵系统的扫描性能。在此，我们建立了相控阵-透镜系统中高方向性波束扫描的界限，并表明非局域介质超透镜可以接近这些极限运行。与抑制互耦的传统超透镜不同，我们的方法利用非局域电磁相互作用来横向重新分配能量，并扩展孔径上相位相干的空间宽度。这使得使用传统线性渐进相位对均匀激励的平面相控阵进行高效波前工程成为可能。我们进一步揭示了衍射和倏逝波在决定最大相干孔径扩展和方向性增强中的作用。由此产生的角信道界限确定了无源线性相控阵-透镜系统的两种不同运行模式：扫描分辨率增强和保持扫描范围的方向性增强。在这些极限的指导下，我们推导出与几何无关的设计方程，并为无源线性超透镜开发了基于伴随的逆向设计框架，使得平面和圆柱形实现能够接近基本极限运行。我们实验验证了一种紧凑的圆柱形超透镜，它保持了具有3.5λ0宽孔径的相控阵的50°扫描范围和扫描分辨率，同时提供了2.5至3.5分贝的峰值方向性增加。这些结果确立了非局域介质超透镜作为相控阵中衍射受限波前工程的实用平台。
英文摘要
Wide-angle beam steering with high directivity is fundamentally limited by diffraction, restricting the scan performance of phased-array systems. Here, we establish the bounds governing beam steering with high directivity in phased-array--lens systems and show that nonlocal dielectric metalenses can operate close to these limits. Unlike conventional metalenses that suppress mutual coupling, our approach exploits nonlocal electromagnetic interactions to laterally redistribute energy and expand the spatial width of phase coherence across the aperture. This enables efficient wavefront engineering for uniformly excited planar phased arrays using conventional linear progressive phasing. We further reveal the roles of diffraction and evanescent waves in determining the maximum coherent-aperture expansion and directivity enhancement. The resulting angular-channel bounds identify two distinct operating regimes for passive linear phased-array--lens systems: scan-resolution enhancement and directivity enhancement with preserved scan range. Guided by these limits, we derive geometry-independent design equations and develop an adjoint-based inverse-design framework for passive linear metalenses, enabling planar and cylindrical implementations that operate close to the fundamental limits. We experimentally validate a compact cylindrical metalens that preserves the $50^\circ$ scan range and scan resolution of a phased array with a $3.5λ_0$-wide aperture while providing a $2.5$--$3.5\,\mathrm{dB}$ increase in peak directivity. These results establish nonlocal dielectric metalenses as a practical platform for diffraction-limited wavefront engineering in phased arrays.
