Design of high power and high efficient multimode feed by MMT

In an HPM radiation system, the horn feeds which have high power capacity and favorable radiation performance are required. The multimode and smooth-wall horn can fulfill the requirement. Based on the single step mode-matching technololgy, the method to get the scatter matrix of the smooth-profile horn was presented. By the method, the process of modes coupling which happened when TE11 mode was incident to horn feed was analyzed. The relationship of mode coupling and the change of radiation performance was investigated. Through simulation and selection, the primary design model, which had high power capacity above 1.5 GW and favorable radiation performance, was obtained and measured. Excellent correspondence between the experimental result and theory was demonstrated.