Research And Design Of Holographic Antennas

The research of holographic antennas has become a hot topic. The concept of holographic antenna is derived from the optical holography. However, it shows a great application prospect in microwave frequencies. The holographic antenna structure is simple and the configuration of its feed is flexible. The certain kind of antenna is able to realize the desired radiation characteristics by the modulation of the holographic structure constructed by the interference pattern.This paper expounds the research status of the holographic antenna and some problems appeared in the researches. Also, the research background is illustrated and then the main work is determined, as well as the research approaches and the assistant software. The main work in this paper is demonstrated as follows.Firstly, the interference pattern is obtained based on the principle of the holography. Given the minimum of the interference, the holographic structure is constructed by etching the metallic strips on the position of the minimum values. Therefore, the original holographic antenna is designed and measured.Then, the miniaturization is realized in view of the bigger profile of the original holographic antenna. The key purpose is to increase the effective area of the aperture. The method of the miniaturization can be determined qualitatively by the analysis of energy distribution on the surface of the holographic structure, i.e., cutting the redundant and invalid scattering region out from the original holographic structure. In order to increase the gain, a Perfect Magnetic Conductor(PMC) truncation is designed at proper position, with the configure simplified and the cost of the manufacture reduced. The miniaturized antenna is manufactured and measured and it is shown that the area of the original is reduced dramatically and the gain of the miniaturized antenna is 3.61 d B in measurement higher than that of the original one.Also, the novel design of the application of holographic antenna in antenna test isimplemented. For the high accuracy and cost of the reflectors used in the traditional compact antenna test range(CATR), the holographic structure is designed to replace the reflectors and the holographic compact antenna test range is designed. The planar holographic structure and much lower surface accuracy requirement make manufacturing of a hologram simpler and less expensive than that of a re?ector. And a good quiet zone is produced.Finally, in order to solve the problems of the alignment and fixing of the feed, the complanation of the CATR is completed. Based on the analysis of the complanation of the holographic antenna, the antenna array, with the certain printed dipole above as its element, is used as the feed of the complanation of the hologram-based CATR. The holographic structure is constructed the same way as before and then is printed on the same material plate with the feed. The structure obtained is easy to integrate. Also, there is no need to fix and align physically with the occupation of the CATR reduced. More importantly, the characteristics of the quiet zone produced by the complanation design accords with the magnitude and the phase requirements of the quiet zone basically. A better quiet zone can be obtained by further optimization.