Radiation From an Aperture Antenna in the Near-Field of a Reflecting Surface

The article discusses the use of Green’s functions for analyzing the radiation of aperture antennas, specifically the open end of a rectangular waveguide. The article explains how the concept of a directional pattern is not applicable in real systems where antennas are located close to reflecting objects affecting antenna matching. The calculation of antenna characteristics becomes significantly more complicated in such cases. Green’s functions are used as a method of electrodynamics to determine the radiation parameters of a point source, which is used as an element for modeling the field of the considered aperture antenna. The resulting graphs and data confirm that the antenna has a good match with the presence of a reflective surface. This approach enables us to solve the problem of aperture antennas (e.g., slits, slots, waveguides, horns, reflectors, lenses) that emit close to the boundaries of different media. The article’s methodology enables the design of such systems to consider the best location for the sensor above the interface, including consideration of the sensor’s electro-physical properties and subsurface reflective objects.