| Multiple-beam antenna plays a key role in three-dimensional radar. In this thesis, onekind of dielectric lens antenna system which can lead to greatly increased scan coveragehas been investigated. The system is composed of feed antennas and dielectric sphericallens. The feed antennas are placed around the sphere; the beam scan can be achieved by theswitching of the feed. The main research is:ⅰ) The basic principle and analytical method of the lens antenna are discussed.A general model of the dielectric lens antenna is built and all kinds ofefficiency have been defined.ⅱ) The volume of the taped slot antenna is very big, so yagi antenna is designedby HFSS. The whole length of this antenna is only 1.4λ, while the taped slotantenna will need 5λin the same condition.ⅲ) A few parameters which can inference the performance of the system havebeen invested especially to the efficiency and far-field radiation properties. (a)The index of refraction of the lens mainly influence the focusing properties(b) The bigger the radius of the sphere, the narrower beam width of theantenna. (c) The distance between the sphere and the feed antenna mainlyinfluence the efficiency of the system and the side lobe (d) Along with theincrease of the feed antenna's beam width, spillover efficiency will increase,but the beam width of the system will decrease. (e) Otherwise the researchwork also invests how cutting the spheres influence the efficiency of thesystem.ⅳ) The work discussed above has been utilized to design a multiple beamhomogenous dielectric spherical lens antenna system at 14GHz, the beamsoverlap at 3dB level, and scan coverage can reach 360°by the 20 beamsand the efficiency of the system can reach 50%. |
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