An Electromagnetically Consistent and Mutual Coupling-Aware Near-Field Communication Model for Holographic MIMO

As a potential technology to support the extreme requirements of next-generation communications, holographic multiple-input multiple-output (H-MIMO) refers to arrays with a large number of individually controlled and densely deployed antennas. An important challenge to realize this innovative concept is the need to integrate information theory, electromagnetic theory and circuit theory in modeling, which is also required for electromagnetic information theory (EIT). This paper aims to connect information theory and electromagnetic theory using circuit theory to provide electromagnetically consistent and mutual coupling-aware near-field communication models for H-MIMO systems. Specifically, first, the considered H-MIMO system model is given and represented as a linear multiport network in circuit theory. Unlike the mainstream models that only consider the wireless propagation environment, the circuit-based model is physically consistent and considers the radio frequency components, mutual coupling between different antenna elements, noise, etc. Second, the mutual coupling and propagation effects are represented in the circuit model by the impedance, which requires relating the quantities of the circuit to the fields generated by the antenna. The relationship between the quantities of the circuit and the fields generated by the antenna is given according to the reciprocity and reaction theorems. Furthermore, the method of moments (a computational electromagnetic method) is introduced to calculate the impedance in the line-of-sight case. Finally, the integration of the physical model with the digital model provides a framework for the design of H-MIMO. In the numerical simulations, the H-MIMO performance is provided using the proposed model.