Modelling aperture antennas in the near- and far-field regions using subarrays of equivalent uniformly illuminated apertures.

This paper develops and presents an application of Huygen's principle herein referred to as the equivalent uniformly illuminated aperture method (EUAM). This method is used to predict the E-field patterns of aperture antennas in both the near- and far-field regions. In applying this method the radiating aperture is mathematically replaced by an array of smaller, uniformly illuminated aperture sources. Thus the true aperture field is approximated in a step-wise manner by the individual sub-apertures that are uniformly illuminated by the field at the point on the aperture where the sub-aperture is located. This method is suitable for analysing any antenna if its aperture fields are known. Comparisons are made between this method, an equivalent dipole method, and experimental measurements. These calculations and measurements show that the EUAM is more accurate (especially in the near-field region), is much simpler to implement, and requires less execution time than the equivalent dipole method.