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A Survey of Pinching-Antenna Systems (PASS)

Yuanwei Liu, Hao Jiang, Xu Gan, Xiaoxia Xu, Jia Guo, Zhaolin Wang, Chongjun Ouyang, Xidong Mu, Zhiguo Ding, Arumugam Nallanathan, Octavia A. Dobre, George K. Karagiannidis, Robert Schober

TL;DR

PASS is presented as a waveguide-based pinching-antenna system that enables large-scale reconfigurability and LoS creation. The survey develops physics-informed models and abstract multiport networks, and introduces architectures SWAN, C-PASS, and M-PASS, together with sensing-enabled extensions. It reviews performance analyses for communications (rate and outage) and sensing (CRLB and sensing rate), and surveys optimization and learning methods from structure-based, population-based, to game-theoretic and DL/GNN approaches. It also discusses practical challenges—uplink modeling, PA reciprocity, hardware constraints, and maintenance—and outlines wireless feeding and ML-enabled sensing as future directions.

Abstract

The pinching-antenna system (PASS), recently proposed as a flexible-antenna technology, has been regarded as a promising solution for several challenges in next-generation wireless networks. It provides large-scale antenna reconfiguration, establishes stable line-of-sight links, mitigates signal blockage, and exploits near-field advantages through its distinctive architecture. This article aims to present a comprehensive overview of the state of the art in PASS. The fundamental principles of PASS are first discussed, including its hardware architecture, circuit and physical models, and signal models. Several emerging PASS designs, such as segmented PASS (S-PASS), center-fed PASS (C-PASS), and multi-mode PASS (M-PASS), are subsequently introduced, and their design features are discussed. In addition, the properties and promising applications of PASS for wireless sensing are reviewed. On this basis, recent progress in the performance analysis of PASS for both communications and sensing is surveyed, and the performance gains achieved by PASS are highlighted. Existing research contributions in optimization and machine learning are also summarized, with the practical challenges of beamforming and resource allocation being identified in relation to the unique transmission structure and propagation characteristics of PASS. Finally, several variants of PASS are presented, and key implementation challenges that remain open for future study are discussed.

A Survey of Pinching-Antenna Systems (PASS)

TL;DR

PASS is presented as a waveguide-based pinching-antenna system that enables large-scale reconfigurability and LoS creation. The survey develops physics-informed models and abstract multiport networks, and introduces architectures SWAN, C-PASS, and M-PASS, together with sensing-enabled extensions. It reviews performance analyses for communications (rate and outage) and sensing (CRLB and sensing rate), and surveys optimization and learning methods from structure-based, population-based, to game-theoretic and DL/GNN approaches. It also discusses practical challenges—uplink modeling, PA reciprocity, hardware constraints, and maintenance—and outlines wireless feeding and ML-enabled sensing as future directions.

Abstract

The pinching-antenna system (PASS), recently proposed as a flexible-antenna technology, has been regarded as a promising solution for several challenges in next-generation wireless networks. It provides large-scale antenna reconfiguration, establishes stable line-of-sight links, mitigates signal blockage, and exploits near-field advantages through its distinctive architecture. This article aims to present a comprehensive overview of the state of the art in PASS. The fundamental principles of PASS are first discussed, including its hardware architecture, circuit and physical models, and signal models. Several emerging PASS designs, such as segmented PASS (S-PASS), center-fed PASS (C-PASS), and multi-mode PASS (M-PASS), are subsequently introduced, and their design features are discussed. In addition, the properties and promising applications of PASS for wireless sensing are reviewed. On this basis, recent progress in the performance analysis of PASS for both communications and sensing is surveyed, and the performance gains achieved by PASS are highlighted. Existing research contributions in optimization and machine learning are also summarized, with the practical challenges of beamforming and resource allocation being identified in relation to the unique transmission structure and propagation characteristics of PASS. Finally, several variants of PASS are presented, and key implementation challenges that remain open for future study are discussed.
Paper Structure (58 sections, 3 equations, 17 figures, 12 tables)

This paper contains 58 sections, 3 equations, 17 figures, 12 tables.

Table of Contents

  1. Introduction
  2. Flexible Antennas
  3. Pinching-Antenna System (PASS)
  4. Motivation and Contribution
  5. Notations and Organization
  6. PASS Fundamentals
  7. PASS Signal and Channel Models
  8. PA Implementation and Hardware Models
  9. Small Dielectric Scatterer (SDS) Model
  10. Directional Coupler Waveguide (DCW) Model
  11. PA Multiport Network Model
  12. Discussion and Outlook
  13. Hardware Limitations
  14. System Design Simplifications
  15. Optimization Limitations
  16. ...and 43 more sections

Figures (17)

  • Figure 1: Condensed overview of this survey on PASS.
  • Figure 2: Illustration of signal propagation in PASS.
  • Figure 3: Illustration of the evanescent and propagation fields for rectangular and circular waveguides. The figures illustrate the power density at 28 GHz for a dielectric core with a refractive index of 2.1 surrounded by air. Only the fundamental mode is plotted.
  • Figure 4: Three EM-level hardware implementations for PAs.
  • Figure 5: Multiport network model for PAs.
  • ...and 12 more figures