Field Distribution Features of Linearly Polarized Field of Plane Aperture

Abstract

In this study, we describe the specific features of the near-field distribution of a uniformly illuminated aperture. An analytical method based on physical optics in the time domain is used to calculate the field intensity. The primitive impulse response function makes it possible to calculate the near-field distribution of the antenna. The difference in the amplitudes of the fields during the observation point shift along the X and Y coordinate axes can reach up to 13% of their maximum relative values. This difference should be considered when calculating the antenna radiation patterns. At the end of this paper, we present the results of the comparison obtained using three methods: geometrical theory of diffraction (GTD), plane wave spectrum approach (PWS), and primitive impulse response function (IRF) method. In the near field of relatively small apertures (with respect to wavelength), the results of all three compared methods (GTD, PWS, and IRF) were very similar. The analytical IRF method, the results of which are given in this paper, is much more effective in terms of computer resources than the plane wave spectrum approach, and even more effective than the geometric theory of diffraction method.

Keywords

• Near field analysis
• physical optics
• aperture antennas
• spatial-frequency characteristics
• ultra-wideband antennas