Analysis And Research Of The Polarization Characteristic And The Key Technology For The Waveguide Slot Antenna

The waveguide slot antenna is a system which digs apertures on the waveguide to obtainquantity of radiant energy, whose feeding and radiant systems are integrative, so that thestructure is light and compact, and own well wind resistance. At the same time, the waveguideslot antenna possess diplex characteristics of both transmission and radiating antenna, and itscoverage rate of signal is well-proportioned, the coupler loss is low and the power capacity ishigh, especially suitable for the environment of high frequency. Base on these characteristicsmentioned above, the waveguide slot antenna has the advantage cannot be replaced in thefield of radar、missile homer and so on, and the polarization characteristic as one of the keytechniques of antenna play a very important role in practice.Beginning with the basic theory of the waveguide slot antenna，the paper first introducedthe surface current distribution of rectangular waveguide on the condition of single-modetransmission，the type of waveguide apertures，radiator mechanism, discussed the equivalentscheme and electrical parameter of apertures, analysis the relationship and influence betweenthe aperture parameter and its performance index. And then this paper introduced thepolarized characteristic of antenna, analysis the form theoretical foundation of all kinds ofpolarized wave, researched the basic theories of the far-field polarized radiation of waveguideaperture. All of these lay a theoretical foundation for the further study.Followed by, based on the theoretical foundation mentioned above, The aperture electricfield vector distribution was obtained by simulating by Ansoft HFSS, and researched thepolarized characteristic of the waveguide slot antenna systematically in this paper, summedup the structure of aperture units which can form vertical and horizontal polarized wave bythe method of polarization synthesis and vector analysis, introduced two kind of classicalcircular polarized aperture unit, researched characteristics of them at the same time, and usingthe functions of scan and optimization of Ansoft HFSS to obtain parameters for design of theseparate “人”aperture unit in the frequency band of X and Ku, and has improved the circularpolarized characteristic compared with the literature.At last, this paper studied and designed a new kind of circular polarized aperture unitbased on the research of the polarized characteristic for the waveguide slot antenna and thetheory of polarization synthesis. This paper obtains the parameters for design by using the functions of scan and optimization of Ansoft HFSS, and then further optimized the parametersby the method of combination of genetic algorithm, the result showed that the circularpolarized axis ratio bandwidth has been widen. Followed by, this paper also provided amethod to analyze the polarized sense of this circular polarized aperture unit, and thesimulation result is consistent with the result of the analysis.