Multi-focus transmitarray antenna in near/far field design

In this paper, the design of single-focused and multi-focused transmitarray antennas in the near-field (NF) or/and far-field (FF) applications are proposed. A unit-cell element consists of a dielectric square box with four identical holes is used. The phase compensation of the unit-cell element depends on changing the hole radii according to the position of the unit-cell, the feeding horn, and the beam direction. The radiation characteristics of 13×13 unit-cell elements transmitarray antenna focused in the near- and the far-field regions are investigated. A single structure multi-focused transmitarray is designed using a chess-board arrangement of the unit-cell elements. Multi-focused transmitarray antennas for FF/FF, FF/NF, and NF/NF are designed and investigated. The phase distributions and the corresponding hole radii for different configurations of the multi-focused transmitarray antennas are presented. The radiation characteristics of different array configurations are investigated and analyzed using a full-wave simulator CST Microwave Studio.