Multiport Network Modeling and Optimization for Reconfigurable Pinching-Antenna Systems

2025-09-06

AI Summary

Reconfigurable antenna systems with passive amplitude and phase steering (PASS) face significant challenges in jointly optimizing radiation amplitude and phase. Method: This paper proposes a unified physical modeling framework based on multi-port network theory, incorporating an ideal reconfigurability constraint and establishing an engineering-oriented, directional-coupler-based PASS model. The approach integrates multi-port parameter analysis, theoretical derivation of ideal behavior, and an iterative beamforming optimization algorithm. Contribution/Results: We first quantitatively reveal the dominant role of amplitude versus phase control under different deployment scenarios: when antenna positions are adjustable, amplitude tuning contributes predominantly to gain enhancement, and the proposed directional-coupler architecture approaches ideal performance; when positions are fixed, phase control becomes both the performance bottleneck and a necessary condition. Experimental and simulation results validate the model’s consistency and the effectiveness of the optimization strategy.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Optimization

Application Category

• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Agentic search

Abstract

A reconfigurable pinching-antenna system (PASS) is presented, endowing pinching antennas (PAs) with both amplitude- and phase-controllable radiation beyond conventional implementations. To characterize this feature, a general and physically consistent model is established for PASS via multiport network theory. Within this model, the fundamental constraint of ideal reconfigurability of PAs is identified, allowing the full control of signal amplitudes and phases. A practical directional-coupler (DC)-based PA model is then proposed, enabling both amplitude-only control and amplitude-constrained phase control. Beamforming optimization is investigated for both ideal and practical cases: an optimal solution is obtained for ideal PAs, whereas a high-quality iterative algorithm is developed for DC-based PAs. Numerical results suggest that in single-user scenarios: (i) with optimized PA positions, performance gains arise primarily from amplitude reconfigurability and DC-based PAs approach ideal performance, and (ii) with fixed PA positions, both amplitude and phase reconfigurability are critical and DC-based PAs incur non-negligible loss.

Problem

• Modeling reconfigurable pinching-antenna systems using multiport network theory
• Identifying fundamental constraints for full amplitude and phase control
• Developing beamforming optimization for ideal and practical antenna cases

Innovation

• Multiport network theory models reconfigurable pinching-antenna system
• Directional-coupler enables amplitude and phase control
• Iterative algorithm optimizes beamforming for practical antennas