Surface Antenna Near-field Mutual Coupling Study

The research on antenna mutual coupling has been one of important problems in the area of Electromagnetic Compatibility. The thesis focuses on the research on the mutual coupling between independent aperture antennas.As for this problem, the thesis firstly discusses three methods used to compute antenna radiation pattern in the near-axis zone: Surface Integration, Aperture Integration, and Plane Wave Spectrum. As an example, the thesis use AI method to compute near-field pattern of typical pyramidal horn antenna at different distance, and use PWS method to compute far-field pattern of typical pyramidal horn antenna, drawing a conclusion about relationship between numerical integration in spectrum domain and integration grid and spectrum of aperture field. Then, the thesis introduces a way to compute far-axis zone field of aperture antennas-Geometrical Theory of Diffraction. Here, the thesis gives an improvement of transitional function approximation, and deduces some formulas used to compute near field at far-axis zone field of pyramidal horn antennas. At last, the thesis computes near-field mutual coupling between two pyramidal horn antennas in H-plane. The computational data agree well with experimental data.