Achievable Rate of Near-Field Communications Based on Physically Consistent Models

This paper introduces a novel information-theoretic approach for studying the effects of mutual coupling (MC), between transmit and receive antennas, on overall performance single-input-single-output (SISO) near-field communications (NFC). By incorporating finite antenna size constraint using Chu’s theory under assumption canonical-minimum scattering (CMS), we derive MC two radiating volumes fixed sizes. Expressions self impedances are obtained by use reciprocity theorem. Based circuit-theoretic two-port model SISO radio communication systems, first establish its input-output relationship where noise depends self/mutual unlike conventional independent additive white Gaussian noise. We then characterise achievable data rate given pair sizes, thereby providing an upper bound system physical constraints. Through lens these findings, shed new light influence limits compact antennas.