全息表面上感知互耦合的可移动流体天线：波数域的电路-场统一

中文摘要 AI 辅助

可移动流体天线系统将天线位置作为设计变量，但在亚波长间距下，其性能受互耦合支配，目前该耦合的建模分为两个互不关联的传统方向：基于元件级常数的电路理论阻抗矩阵，以及具有范数型功率约束的场理论核。本文将二者统一：从全息表面的阻抗核出发，通过坡印廷锚定平衡将其电阻部分识别为欧姆功率与辐射功率之和，电抗部分识别为储能不平衡；电路-场等价性表明，多端口阻抗矩阵是端口间距处采样得到的核，采用单一闭合球汉克尔形式。在波数域中，电阻核随孔径尺寸渐近对角化：可见模式以闭式代价辐射，倏逝模式仅耗散功率；灵活端口成为恒模码字，其耦合为谱权重的拉回。随后，在物理功率和电压约束下，将感知耦合的多用户和速率最大化问题表述为预编码器与端口位置的优化问题，通过加权最小均方误差（weighted-MMSE）和带闭式梯度的投影梯度步骤求解；模态松弛为每种端口配置提供上界，并通过基于快速傅里叶变换（FFT）的码字投影初始化搜索。半波长推论和超方向性余量可量化耦合何时有害、何时有益。

英文摘要

Movable and fluid antenna systems turn antenna position into a design variable. At sub-wavelength spacings, however, their behavior is governed by mutual coupling, modeled today by two disjoint traditions: circuit-theoretic impedance matrices with element-level constants, and field-theoretic kernels with norm-type power constraints. This paper unifies the two. Starting from the impedance kernel of a holographic surface, a Poynting-anchored balance identifies its resistive part with ohmic plus radiated power and its reactive part with stored-energy imbalance, and a circuit-field equivalence shows that the multiport impedance matrix is the kernel sampled at the port separations, in a single closed spherical-Hankel form. In the wavenumber domain the resistive kernel asymptotically diagonalizes in the aperture size: visible modes radiate at closed-form prices, evanescent modes only dissipate, and a flexible port becomes a constant-modulus codeword whose coupling is the pullback of the spectral weight. Coupling-aware multi-user sum-rate maximization over precoders and port positions is then formulated under physical power and voltage constraints and solved by weighted-MMSE and projected-gradient steps with closed-form gradients. A modal relaxation upper-bounds every port configuration and seeds the search by FFT-based codeword projection. A half-wavelength corollary and a superdirectivity margin quantify when coupling hurts, and when it helps.

发表机构

• Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg（卢森堡大学安全、可靠性与信任跨学科中心）

机构由 AI 辅助整理，请以论文原文为准。