Switched-Feed Pinching-Antenna Systems for Wideband Terahertz Communications

2026-07-14

AI Summary

This work addresses the significant waveguide attenuation in the terahertz band, which severely limits the performance of conventional Pinching antenna systems for broadband communications. To overcome this challenge, the authors propose a Switched-Feeding Pinching Antenna System (SF-PASS), introducing the first unified terahertz propagation model that jointly accounts for waveguide loss, atmospheric absorption, molecular re-radiation noise, and beam misalignment. The system incorporates a switched-feeding architecture with an insertion-loss threshold criterion and a cluster layout strategy that equalizes signal-to-interference-plus-noise ratio (SINR) at band edges. Through coordinated multi-waveguide feeding and closed-form analytical optimization, SF-PASS achieves substantially improved spectral efficiency at optimal operating frequencies while approaching the performance of large-scale antenna arrays at reduced hardware cost.

Abstract

The pinching-antenna system (PASS) uses dielectric particles along a low-loss waveguide as reconfigurable passive radiators. Existing analyses conclude that the in-waveguide attenuation is negligible at low frequencies and millimeter wave bands; we show this fails at terahertz (THz), where realizable waveguide losses are dramatically larger. We develop a unified wideband THz-PASS propagation model integrating in-waveguide attenuation, atmospheric absorption, molecular re-radiation noise, and beam squint. Closed-form results follow: a band-averaged coherence factor; a cluster-center placement satisfying a band-edge SINR equalization condition; an associated placement-inversion threshold; and a proposed \emph{Switched-Feed PASS} (SF-PASS) architecture in which a centrally located radio-frequency switch routes the signal among multiple waveguide segments, with a closed-form insertion-loss payoff threshold. Numerical evaluation at the best PASS-compatible THz operating point shows that SF-PASS substantially outperforms single-feed PASS in spectral efficiency and is competitive with a large-scale antenna array at much lower hardware costs.

Problem

• Terahertz communications
• Pinching-antenna system
• Waveguide attenuation
• Wideband propagation
• Spectral efficiency

Innovation

• Switched-Feed PASS
• terahertz communications
• waveguide attenuation
• spectral efficiency
• reconfigurable antenna