Extra DoF of Near-Field Holographic MIMOCommunications Leveraging Evanescent Waves

TL;DR

This paper explores how evanescent waves can enhance the spatial degrees of freedom and channel capacity of near-field holographic MIMO systems with constrained antennas, demonstrating significant potential through numerical analysis.

Contribution

It introduces a method to leverage evanescent waves for increasing DoF and capacity in near-field MIMO, extending analysis to isotropic scattering environments.

Findings

Evanescent waves significantly increase DoF in near-field MIMO.

Numerical results show capacity improvements with evanescent wave utilization.

Method can be extended to non-isotropic scattering environments.

Abstract

In this letter, we consider transceivers with spatially-constrained antenna apertures of rectangular symmetry, and aim to improve of spatial degrees of freedom (DoF) and channel capacity leveraging evanescent waves for information transmission in near-field scenarios based on the Fourier plane-wave series expansion. The treatment is limited to an isotropic scattering environment but can be extended to the non-isotropic case through the linear-system theoretic interpretation of plane-wave propagation. Numerical results show that evanescent waves have the significant potential to provide additional DoF and capacity in the near-field region.