An Analysis of Effects of Structural Factors of a Conical-Horn Antenna on its Electromagnetic Performance

In the antenna system of a radio telescope its feed is so important that its properties can directly affect the electromagnetic performance of the entire antenna system.Considering that the influence of the structure of a feed on an antenna system has not yet been extensively studied, we take a typical horn feed, a conical-horn antenna, as a research subject to evaluate its structural influence.By using the 3-dimensional electromagnetic simulation software CST STUDIO SUITE12.0, and modeling the structure of a conical-horn antenna, we have carried out simulations of certain effects of the antenna structure on the electromagnetic performance.The effects include those from the conicity of the waveguide and those from the ellipticity/irregularity of the radiation-aperture shape.By examining the pattern of electromagnetic fields far from the antenna, we have found that the influence of the conicity of the waveguide is little, but the influence of the irregularity of the radiation-aperture shape is prominent.Within certain limits, the ellipticity of the radiation aperture also has little influence, with the measured S11 of the antenna less than -15dB.Our study shows a new approach of studying effects of structural factors of a conical-horn antenna on its electromagnetic performance, and our conclusions can provide useful suggestions for designing or manufacturing a conical horn.