Spherical wavefunction analysis of radiation from the pyramidal horn

The pyramidal horn may be approximated as a quasi-pyramidal horn if the flare angles that describe it are measured from the same point. The quasi-pyramidal horn model is analyzed using spherical wave functions. Only the dominant TE/sup r01/ mode is considered. To simplify the boundary condition it is useful to consider the horn enclosed by a perfectly conducting sphere concentric to the horn apex. A finite spherical wave expansion (SWE) is used to describe the fields outside the sphere, with only outgoing waves needed. A comparison between the predicted and the measured far-field E-plane ( phi =90 degrees ) patterns was made with good agreement. Comparison with Jull´s results (1981) shows that the SWE method is more accurate in predicting the radiation pattern than the aperture integration method.<>