Research Of Octave Circular Polarization Horn Antennas

Circular polarization horn antenna is applied broadly in many regions ,such as communication,navigation and control-guide, due to its nice directivity and wide spectrum band. In order to satisfy the requirement of projects, the thesis analyses and designs a circular polarization horn antenna, which works in octave bandwidth and possesses the capacity of better amplifying,less VSWR and lower axial ratio.This thesis comprises detailed contents below:(1) The antenna's feeding part adopts the transition of coaxial-ridge-rectangular wave guide. It is assisted with step and gradual changing impedance matching. The coaxial feeding part has the capacities of wide spectrum band and less VSWR.(2) This thesis analyses the theory about how to generate circular polarization wave from clapboard polarizer,corrugated waveguide polarizer and dielectric-sheet polarizer. The S parameter of the clapboard polarizer has been introduced. The reason how the parameters of corrugated waveguide polarizer and dielectric-sheet polarizer impact on the circular polarization capability is analyzed by using the numerical method. Both the corrugated waveguide polarizer and dielectric-sheet polarizer have achieved the antenna's standards.(3) The theory about power divider orthogonal mode transducers is clarified. According to simulation, a method of disturbing the output end's square calibre wave guide faintly is proposed to solve the problem about the degenerate mode. The simulation result shows that the power is divided equally.(4) The practical problems, such as project feasibility and machining error, have been considered when designing the antenna.Summing up each part's analysis and design above, this thesis proposes two design schemes of circular polarization horn antenna. Corrugated waveguide polarizer is adopted in one scheme and dielectric-sheet polarizer is used in the other scheme. The simulation results of the two schemes have meet the need of antenna design.