A General EM-Based Channel Model for Reconfigurable Antenna Systems

TL;DR

This paper introduces a comprehensive EM-based channel model for reconfigurable antenna systems, capturing the effects of antenna position and orientation on channel gain, validated against simulations, and highlighting the importance of dynamic orientation adjustments.

Contribution

It presents a novel EM-based channel model using spherical vector wave expansion tailored for RASs, addressing limitations of previous models and enabling performance optimization.

Findings

A new EM-based channel model accurately predicts channel gains.

Dynamic antenna orientation can improve communication rates by up to 70%.

Model validation shows excellent agreement with simulation software.

Abstract

Reconfigurable antenna systems (RASs), such as fluid antennas and movable antennas, are poised to play a pivotal role in sixth-generation (6G) systems by dynamically adapting the antenna elements for system performance enhancement. However, unlocking their full potential requires channel models that accurately capture the influence of antenna configurations on the radiation, propagation, and reception of signals. Existing channel models suffer from several limitations, such as neglecting polarization effects, being restricted to specific antenna types, or relying on oversimplified assumptions. In this paper, we propose a general electromagnetic (EM)-based channel model grounded in spherical vector wave expansion (SVWE). The proposed EM-based channel model captures the impact of antenna position and orientation on the channel gain, thereby making it particularly well-suited for RASs. The effectiveness and accuracy are validated through comparisons with commercial simulation software, demonstrating excellent agreement in predicted channel gains. Moreover, it is shown that antenna orientation is a critical factor governing communication performance, and that dynamically adjusting the antenna orientation yields up to 70% improvement in achievable communication rate compared to a fixed-antenna configuration.