A parasitic coupling network concept for mutual coupling utilization in wideband multielement antenna arrays

• Introduces a parasitic coupling network (PCN) derived from rigorous formulas to widen the active reflection coefficient (ARC) bandwidth of unbalanced-excitation antenna arrays. • Achieves 10.9% and 30.8% bandwidth enhancements in two-element H-plane and E-plane dual-layer coupled microstrip arrays, respectively. • Scales successfully to multielement arrays (3- and 5-element linear, 8×2 planar), exhibiting approximately 40% overlapped ARC bandwidth with stable radiation patterns and gains. • Demonstrates strong potential for large-scale wideband scanning arrays, leveraging mutual coupling as a beneficial resource rather than a performance-limiting factor.