Singular Metric for Antenna Array Mutual Coupling: Unveiling the Array Coupling Index (ACI)

In this paper, we present a novel approach for quantifying mutual coupling within antenna arrays. Our method introduces a unified metric, referred to as the Array Coupling Index (ACI), which succinctly captures the collective mutual coupling effect among array elements. The formulation reveals that mutual coupling is intricately linked to impedance matching and provides insight into the worst-case coupling scenario within a specific array configuration. To demonstrate the efficacy of our approach, we analyze several illustrative examples, showcasing the effectiveness of our method in characterizing and understanding mutual coupling phenomena within antenna arrays.