Performance Comparison and Selection Criterion of Sparse Array for Near-Field Focusing

Near-field focusing performance of different sparse arrays with grid topologies is calculated and compared in this paper. Firstly, the near-field characteristics based on the square, circular and regular triangular topologies are calculated accurately. The correctness of the calculation is verified by the simulation. It is found that the circular sparse array has the best performance in sparsity and focusing ability among three topologies. Then, the influence of the regular change in the element distance of the circular sparse array is discussed. The best selection criterion for the near-field focusing sparse array antenna is that the distance between two elements on the ring and the distance between two rings are two constants.