Investigation of sparse near‐field focusing array antenna with different topologies

Abstract

The method to efficiently design a sparse near‐field focusing sparse array antenna is introduced here. First, the calculation model and analysis method of three array topologies including the square grid, the circular grid, and the regular triangular grid are established. The evaluation criterion is the lowest sparsity under the condition that the focusing performance of the sparse array approaches to that of a referenced focusing array with the element spacing of a half of one wavelength. After comparing the focusing performance of these array antennas with different grids, the circular‐grid array is the optimal one and selected to further discuss the influence of different topology parameters. The optimal sparse near‐field focusing array should have the constant distance between two adjacent rings and increase three elements compared with the last ring. Finally, the method based on the proposed selection criteria is employed to design a sparse near‐field focusing sparse array. The correctness of the method has been validated by the full‐wave simulated results.