An Equivalent Excitation Method for Planar Phased Array Scanning Based on Mutual Coupling in Active Element Patterns

In planar phased arrays, mutual coupling significantly impacts the beam pointing accuracy. During wide-angle scanning, increased phase differences between elements lead to more pronounced mutual coupling effects, which are also reflected in the degradation of the active standing wave. This paper proposes an equivalent excitation method based on mutual coupling in active element patterns for planar phased array scanning. The method analyzes the change in the active element patterns and establishes the relationship between the equivalent and desired excitations using a mutual coupling matrix. By setting excitation and observation points at the desired beam pointing location, the method constructs a simplified equation related to the mutual coupling matrix. The mutual coupling matrix is optimized using corresponding samples, with regularization introduced to prevent overfitting and accelerate the convergence process. Simulations on an $8 \times 8$ array demonstrate that the equivalent excitation, even without parameter optimization, effectively corrects beam pointing errors to within 0.6 degrees.