AN ANALYSIS OF MULTIMODE CONICAL HORN ANTENNAS WITH FLARE-ANGLE CHANGES BY USING GENERALIZED TELEGRAPHISTS EQUATION

A multimode conical horn antenna can realize a rotationally symmetric radiation pattern with a low cross polarization level by exciting a do minant 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 analy sis of a flared multimode conical horn antenna using a generalized tel egraphist'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 va lidity 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.