In this chapter, we investigate the mathematical foundation of the modeling and design of
reconfigurable intelligent surfaces (RIS) in both the far-and near-field regimes. More …

With antenna spacing much less than half a wavelength in confined space, holographic
multiple-input multiple-output (HMIMO) technology presents a promising frontier in next …

3D spot beamfocusing (SBF), in contrast to conventional angular-domain beamforming,
concentrates radiating power within very small volume in both radial and angular domains in …

Traditional discrete-array-based systems fail to exploit interactions between closely spaced
antennas, resulting in inadequate utilization of the aperture resource. In this paper, we …

In this paper, we develop an effective degrees of freedom (EDoF) performance analysis
framework specifically tailored for near-field XL-MIMO systems. We explore five …

To meet the stringent requirements of next-generation wireless networks, multiple-input
multiple-output (MIMO) technology is expected to become massive and pervasive …

Holographic multiple-input multiple-output (HMIMO) systems constitute a promising
technology in support of next-generation wireless communications, thus paving the way for a …

Holographic MIMO communications, enabled by large-scale antenna arrays with quasi-
continuous apertures, is a potential technology for spectrum efficiency improvement …

This article conceives a unified representation for near-field and far-field holographic
multiple-input multiple-output (HMIMO) channels, addressing a practical design dilemma:" …

Spot beamfocusing (SBF) is the process of focusing the signal power in a small spot-like
region in the 3D space, which can be either hard-tuned (HT) using traditional tools like …