Design of phase-correcting zone plate antennas for microwave and millimeter-wave applications using a full electromagnetic analysis

At optical frequencies, the features of a zone plate are electrically large, so geometrical and scalar theories are adequate for their analysis. At microwave and millimeter-wave frequencies, however, this is often no longer true, and a full electromagnetic analysis is required to obtain accurate results. In this paper, the body-of-revolution finite-difference time-domain (BOR-FDTD) method is used to study the performance of the grooved-dielectric, phase-correcting Fresnel zone plate antenna. Graphs are presented that examine the effect of various parameters on the focusing ability of these antennas, such as the focal length F, the diameter D, the number of full-wave zones N, and the number of subzones per full-wave zone P. This information should be useful to the designers of these antennas.