论文简报
cs.IT 2605.26714v1 值得读

Amplitude-Tunable Pinching Antenna Systems: Single-Mode Phase-Mismatch Radiation and Multiuser Beamforming

Askin Altinoklu, Leila Musavian

发布日期：2026-05-26 08:54 相关性：1.0000 价值：0.7800 分类：cs.IT eess.SP
arXiv 摘要 PDF 原文 网页正文

摘要

Pinching antenna systems (PASS) enable reconfigurable radiating elements and extended line-of-sight communication, mitigating path loss effects. However, existing designs lack fully controllable radiation weights, as they are governed by structural parameters rather than explicitly assigned variables. In this paper, we introduce a new degree of freedom (DoF) for PASS by enabling radiation weight control through phase-mismatch manipulation of guided waves under single-mode excitation within a coupled-mode framework. By tuning the propagation constants of pinching antennas, independent complex-weight control of individual elements is achieved, transforming PASS into a weight-adaptive analog beamforming architecture. Based on this principle, we present a physics-based hardware model that provides a unified framework for both amplitude-tunable pinching beamforming and conventional equal-power radiation models, ensuring compatibility with existing PASS implementations, such as movable setups. To evaluate the proposed model, we formulate a sum-rate maximization problem for hybrid precoding in multiuser downlink systems and solve it using an alternating optimization framework that combines weighted minimum mean square error-based digital precoding with genetic algorithm-based optimization of PASS configurations, including various scenarios such as weight tuning, antenna movability, and discrete activation. Numerical results demonstrate that the amplitude-tunable PASS architecture achieves consistent performance gains over conventional arrays and existing PASS schemes, with pronounced improvements in interference-limited regimes under practical constraints.

相关性判断

high
相关方向
wireless_communications hybrid_precoding beamforming multiuser_mimo
判断依据

Paper is directly in cs.IT/eess.SP and studies PASS-based hybrid precoding, multiuser downlink sum-rate maximization, and beamforming optimization, which are clearly relevant to communications and adjacent information-theoretic wireless research.

价值判断

Directly relevant to cs.IT wireless communications with a clear new PASS degree of freedom: phase-mismatch-based independent complex radiation-weight control. Structure analysis indicates substantial technical content spanning physics-based hardware modeling, hybrid precoding formulation, WMMSE, alternating optimization, and GA-based PASS configuration. Claims include a unifying model for amplitude-tunable and equal-power PASS plus performance gains in multiuser interference-limited regimes, making it worth deeper technical reading.

核心问题与主要方法

核心问题

PASS lacks directly controllable radiation weights for analog beamforming and multiuser hybrid precoding

场景：single-mode pinching-antenna waveguides in a multiwaveguide multiuser downlink MISO hybrid precoding system

主要方法

Single-mode coupled-mode theory models the main waveguide and pinching antenna as a directional coupler with propagation constants beta1 and beta2; their mismatch Delta beta controls power transfer. For a fixed transfer length L0 and symmetric coupling, the T21 radiation coefficient varies with phase mismatch, inducing both amplitude and phase changes in the radiated field. In the feasible range 0 < Delta beta L0 < pi sqrt(3), the normalized power transfer varies continuously between full transfer and radiation suppression, enabling amplitude control. A cascaded multi-antenna signal model accounts for preceding antennas through transmission coefficients, so each element's complex coefficient contributes to the PASS radiation matrix A. Conventional equal-power PASS is recovered as a special case by analytically choosing phase-mismatch values for the active antennas, allowing comparison with discrete activation and movable PASS. The multiuser downlink design alternates between WMMSE digital precoder updates and GA-based optimization of PASS variables such as phase mismatch, activation, and displacement.

关键贡献与后续阅读

关键贡献

Introduces phase-mismatch manipulation of guided waves as a new PASS degree of freedom for controllable per-element complex radiation weights. Derives a physics-based amplitude-tunable PASS hardware model linking propagation-constant tuning, material properties such as effective permittivity, and amplitude-phase radiation response. Builds a unified multi-element signal model in which amplitude-tunable PASS and conventional equal-power radiation models are represented within the same phase-mismatch framework. Formulates multiuser downlink sum-rate maximization for PASS-based hybrid precoding with configurable radiation weights, activation, and movable/equal-power baselines. Applies an AO solver combining WMMSE digital precoding with GA-based PASS configuration search across AT-PASS, DAC-PASS, and MOV-PASS scenarios. Provides simulation evidence that AT-PASS improves sum-rate over fixed arrays and existing PASS schemes, especially at high SNR or larger user counts where inter-user interference dominates.

研究启发

How sensitive are the reported gains to deviations from the weak-coupling, symmetric-coupler, and identical-length assumptions used in the hardware model? Does independent complex-weight control remain accurate when mutual coupling among many closely spaced pinching antennas or fabrication tolerances are included? How much of the performance gain is due to the physical phase-mismatch model versus the larger effective analog-weight search space used by the GA? Are there measured or full-wave EM validation results for the assumed Delta n range, insertion loss, response speed, and quantization behavior in the proposed PASS geometry? Can the optimization be replaced or initialized by a more scalable deterministic method, given the GA cost and lack of global optimality guarantees?

限制与不确定性

Evidence is based on structure analysis only, not full-paper verification. Optimization is heuristic and GA-based, so algorithmic guarantees and practical deployment value may be limited. Impact depends on feasibility of tunable phase-mismatch ranges, quantization, and the single-mode PASS assumption.

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