Research And Design Of Phase Center Of Ultra-wideband Horn Antenna

With the progress and development of science and technology,ultra wide band（UWB）antennas are widely used in military and civil fields.Reflector antennas and satellite navigation antennas are based on their respective phase centers,but the phase centers of antennas have a large deviation in the wide-band range.Therefore,the variation law of the phase center of ultra-wideband antennas is studied and the deviation of the phase center can be narrowed.The scope approach is significant.This thesis firstly introduces the development of ultra-wideband antennas and their phase centers,as well as the antenna design scheme with stable phase centers,then discusses the influence of the structural parameters of horn antennas on the phase centers,and finally,according to the method of loading lenses to modify the field phase distribution,a method is proposed.A method of loading an H-surface metal diaphragm at the aperture of the horn antenna is presented,which narrows the deviation range of the phase center within the design frequency band,and is verified in related types of horn antennas.The main contents of this thesis are as follows:First,the research status and development trend of ultra-wideband antennas,the application scenarios of phase center and antenna design schemes with stable phase center are reviewed.Second,the performance parameters of UWB antenna,the concept of phase center and the common calculation method of phase center are introduced,and the basic principle of lens loading and the influence of different loading methods on the antenna field distribution are summarized.Then,through the radiation principle and design requirements of the horn antenna,the design of the optimal gain pyramid horn antenna working in the X-band is completed,and the performance parameters of the horn antenna and the phase center in the frequency band are obtained by software simulation.The influence of its structural parameters on the deviation range of the phase center is discussed.Taking the X-band optimal gain pyramid horn antenna as a reference,related types of horn antennas with different structures and different frequency bands are designed,and their performance parameters and the deviation range of the phase center are obtained.Finally,based on the method of loading metal diaphragms to modify the aperture phase of lens antennas,a method of loading H-surface metal diaphragms in the horn aperture plane is proposed,and the size,quantity and spacing of the metal diaphragms are reasonably designed to make the X-band optimal gain angle.The maximum deviation of the phase center of the cone horn antenna is reduced from 14.28 mm to 7.23 mm.The design method of the H-surface metal diaphragm is summarized,and it is applied to related types of horn antennas with different structures and different frequency bands.The performance parameters of the metal diaphragm before and after loading and the maximum deviation of the phase center are compared.The deviation range of the phase center is narrowed while the performance is basically unchanged.