Two models of circular horn antenna were simulated using the WIPL-D software. Special attention is devoted to the dielectrically loaded horn antenna. The influence of the dielectric loading is highlighted and it is the most noticeable in radiation back lobe (significantly suppressed if dielectric load is used).
In order to reduce number of unknowns and simulation time, two symmetry planes were successfully used in each model. Both models were simulated very fast with minimum computational requirements, while simulation time is couple of seconds.