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arXiv · 2506.07678

Quasi-Closed-Form Driven Near-Field Flat-Top Beamfocusing with Concentric Circular Vertical Polarized Dipole Array For Large Intelligent Surface Applications

Jiawang Li
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Abstract

This letter presents a near-field flat-top beam synthesis method based on a semi-closed-form approach. First, the feasibility of achieving a flat-top beam in the near field is examined using a closed-form analysis. A circular concentric ring array structure is adopted, and it is observed that circular rings with different radii exhibit distinct gain characteristics along the focal region on the z-axis. Specifically, smaller radii lead to a monotonic increase in electric field strength near the focus, whereas larger radii result in a monotonic decrease. Based on this behavior, parameters such as the number of rings and the initial radius are determined through field superposition. Subsequently, an optimization algorithm is employed to fine-tune the excitation amplitudes of the individual rings in order to suppress sidelobes. The effectiveness of the proposed method is validated through full-wave electromagnetic simulations.

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Jiawang Li. 2025-06-09. Quasi-Closed-Form Driven Near-Field Flat-Top Beamfocusing with Concentric Circular Vertical Polarized Dipole Array For Large Intelligent Surface Applications. https://arxiv.org/abs/2506.07678

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