Research On Lens Antenna Design

The rapid development of wireless communication asks for new antennas and feeding structures.Antennas with broadband,high gain and miniaturized structure have attracted more and more attention from researchers.In this thesis,the design of the lens antenna is studied in detail.The design method of curved conformal lens,high gain plane lens and beam-shaping lens are studied.The design of horn antennas feeding planar lens is also presented synchronously.The chief contributions are as follows:Firstly,the background of lens antenna is introduced followed by its working principle.At the same time,the working principle and the design arts of the phase-shifted surface which is a key technology in lens design are introduced.The geometrical optics method and phase compensation principle which is used in the design of the lens antenna are also shown in detail.Secondly,the design method and steps of the horn antenna which will be used as the feed of the lens antenna will be explained in the thesis.A horn antenna whose working frequency range from 8 to14 GHz has been designed,and the horn has a uniform radiation pattern which meets the requirements to be a lens antenna's feed.Based on the knowledge given above,a design method for cylindrical lens antenna with high gain has been studied.The phase-shift structures(PSS)using two-layer square resonant rings and EBG structure are designed to extend the phase shift range and bandwidth of the cell.At the same time,a cylindrical conformal high directional beam lens antenna is designed use the proposed PSS.The center frequency of the antenna is 10 GHz and the maximum gain is 12 d B in the main direction,and working frequency range from 9 to 10.5 GHz.The simulation results verified that the broadband performance of the phase delay structure and the effectiveness of the cylindrical conformal lens design.Then,the design process of planar lens antenna based on generalized refraction law is also discussed in the thesis.The designs of a phase delay structure combining air hole unit and watering unit are proposed to increase the phase shift range of the unit.Based on this,a lens antenna with high gain is designed.The center frequency of the antenna is 10 GHz.The gain is increased by 17.2 d B by the lens,which verifies the phase compensation capability of the PSS Lens.Finally,based on the generalized refraction law and the method of refraction angle control,a beam-forming conformal lens is designed using the PSS,which can provide a desired flat-top beam.The lens antenna designed in this paper can be applied to communications and other fields.