An analysis of multimode conical horn antennas with flare-angle changes by using generalized telegraphist's equation

Abstract

A multimode conical horn antenna can realize a rotationally symmetric radiation pattern with a low cross polarization level by exciting a dominant mode and higher‐order modes with appropriate composition ratios. One of the mechanisms to generate the higher‐order modes is a flare type in which the flare angle of the horn is varied. This structure is simple and can be made only with a conductor. In this paper, an analysis of a flared multimode conical horn antenna using a generalized telegraphist's equation is described. In the present method, many higher‐order modes are considered in the telegraphist's equation; the results are confirmed to agree well with the measured results and thus the validity of the method is proven. A design method based on the presented analysis procedure is also described. It is confirmed that sufficient accuracy can be obtained in this design. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80 (2):79–89, 1997

Multimode horn antenna with both high efficiency and low cross polarization

“…By using an optimization process, the inner diameter of the horn can be determined in such a way that the evaluation function is minimized. The radiation pattern of the antenna with the derived taper can easily be derived if the aperture plane method based on the modal coefficients on the aperture plane is used [5]. …”

“…Hence, the wave front on the aperture plane is a spherical surface determined by the flare angle. As a result, a phase error on the aperture plane is generated and the efficiency deteriorates [2,5]. To eliminate such phase errors, the present authors have considered suppression of the higher-order modes generated by the phase error.…”