Directivity Enhancement of Movable Antenna Arrays with Mutual Coupling

Fuente: arXiv
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Autori principali: Xu, Wei, Zhu, Lipeng, Ma, Wenyan, Liu, An, Zhang, Rui
Natura: Preprint
Pubblicazione: 2026
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_version_ 1866912970975477760
author Xu, Wei
Zhu, Lipeng
Ma, Wenyan
Liu, An
Zhang, Rui
author_facet Xu, Wei
Zhu, Lipeng
Ma, Wenyan
Liu, An
Zhang, Rui
contents In conventional antenna arrays, mutual coupling between antenna elements is often regarded as detrimental. However, under specific conditions, it can be harnessed to enhance the far-field directivity (i.e., beamforming gain). Theoretically, the directivity of an N-antenna superdirective array over the endfire direction can reach N^{2}, significantly exceeding the directivity of a traditional uncoupled array which is N over all directions. This paper investigates the potential of mutual coupling effects in movable antenna (MA) arrays for directivity enhancement. A low-complexity algorithm called Greedy Search and Gradient Descent (GS-GD) is proposed to optimize the antenna positions for maximizing the array directivity over any given direction, where the antenna positions are first selected sequentially from discrete grid points and then continuously refined through gradient descent (GD) optimization. Numerical results demonstrate that the optimized MA array design by exploiting the antenna coupling achieves significant directivity gains compared to the conventional uniform linear array (ULA) without antenna coupling over all directions. Additionally, the proposed GS-GD algorithm is shown to approach the global optimum closely in most directions.
format Preprint
id arxiv_https___arxiv_org_abs_2603_16472
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Directivity Enhancement of Movable Antenna Arrays with Mutual Coupling
Xu, Wei
Zhu, Lipeng
Ma, Wenyan
Liu, An
Zhang, Rui
Information Theory
In conventional antenna arrays, mutual coupling between antenna elements is often regarded as detrimental. However, under specific conditions, it can be harnessed to enhance the far-field directivity (i.e., beamforming gain). Theoretically, the directivity of an N-antenna superdirective array over the endfire direction can reach N^{2}, significantly exceeding the directivity of a traditional uncoupled array which is N over all directions. This paper investigates the potential of mutual coupling effects in movable antenna (MA) arrays for directivity enhancement. A low-complexity algorithm called Greedy Search and Gradient Descent (GS-GD) is proposed to optimize the antenna positions for maximizing the array directivity over any given direction, where the antenna positions are first selected sequentially from discrete grid points and then continuously refined through gradient descent (GD) optimization. Numerical results demonstrate that the optimized MA array design by exploiting the antenna coupling achieves significant directivity gains compared to the conventional uniform linear array (ULA) without antenna coupling over all directions. Additionally, the proposed GS-GD algorithm is shown to approach the global optimum closely in most directions.
title Directivity Enhancement of Movable Antenna Arrays with Mutual Coupling
topic Information Theory
url https://arxiv.org/abs/2603.16472