Near-Field Array Shaped Multifocus Power Distribution With Dynamic Range Ratio Constraints Using Convex Optimization

The letter addresses precise control of multifocus (MF) power distribution problems in near-field focusing (NFF) planar arrays based on convex optimization. Firstly, a single focal point (FP) focusing problem with reduction of the focal shift (FS) effect and control of the dynamic range ratio (DRR) of excitation amplitudes is formulated as a convex optimization problem. The proposed single FP focusing method obtains superior power distribution in the FP region compared to the existing NFF synthesis methods. Then, the extended single FP focusing method is applied to MF power distribution scenarios with DRR constraints, which effectively reduces the FS effect and achieves preset power distributions. Finally, simulation results indicate that the proposed method demonstrates the excellent performance in terms of the low FS, effective DRR control, and different power distributions for NFF MF problems.