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X-band Broadband Circularly Polarized Feed Design

Posted on:2007-03-24Degree:MasterType:Thesis
Country:ChinaCandidate:R H JianFull Text:PDF
GTID:2208360212960786Subject:Radio Physics
Abstract/Summary:PDF Full Text Request
Start from the vector wave equation for source free region, the hybrid mode field of the cylindrical dielectric waveguide is presented via the method of seperation of variables, Given the aperture field, the radiation field of the conic dielectric horn is forwarded with E mode formula. Under the premise of cross polarization minimal, the mode ratio and hybrid condition equation of conic dielectric horn is derived, and the eigenvalue and dielectric thickness of horn is calculated via Matlab numerical method. Via Matlab programming of far field formula,the relationship between horn dimensions and the beamwidth is analyzed, and one horn whose performances comforms well with experimental results is designed. On basis of derivation of equivalent admittance and impedance corresponding to E type and H type excitation to meander line , the transmission matrix of meander-line unit layer is constructed. Furthermore the transmission matrix of N-layer meander-line polarizer is forwarded via network series-connection analysis method , and thus the transmission coefficient, insert loss , Axial ratio of meander-line polarizer are gained. taking the average axial ratio over 8GHz to 12GHz band as the target function ,The dimensions of 4 layer polarizer is optimized by pattern search method ,and the testing results conforms well with the numeric calculation of HFSS software and theory. At last,the antenna's performance is verified via experiment.
Keywords/Search Tags:hybrid mode, dielectric loaded horn, meander_line, broadband polarizer, transmission matrix Pattern search
PDF Full Text Request
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