Comparative analysis of an open-ended waveguide antenna pattern obtained by exact model and by heuristic approaches

An open-ended waveguide as a front-end radiating component is a wide-spread element of many antenna systems. Though the problem of its radiation pattern calculation is an old one, however, some aspects are not completely developed. One of the most popular method for calculation of radiation characteristics is the Kirchhoff-Huygens approximation. This paper attempts to verify the field of application of the Kirchhoff-Huygens method and develop a surrogate model for intensive calculations. Results indicate that one can use the Kirchhoff-Huygens method for calculation of power patterns as well as polarization and cross-polarization ones with sufficient accuracy for practice purposes. Otherwise, it is possible to apply this approach for calculation of power characteristics in the main lobe direction, while polarization and cross-polarization patterns are still sensitive to error of the approximation model.