Rabe, Hanno; Friedrich, Aline (Institut für Hochfrequenztechnik und Funksysteme, Leibniz Universität Hannover, Appelstrasse 9a, 30167 Hannover, Germany)
Rolfes, Ilona (Lehrstuhl für Hochfrequenzsysteme, Ruhr-Universität Bochum, Germany)
A horn antenna fed by three circular waveguide modes is presented enabling directive imaging. The feed excites the E01 and two orthogonal H11 modes with good mode purity within 2 GHz around the center frequency of fc = 25 GHz. The modes are radiated by a linear tapered horn antenna. The fundamental limits of modal beamsteering are analyzed with the focus on level gauging. Imaging enables the localization of parasitic re??ectors even within the beamwidth of the fundamental H11 pattern making it a promising candidate for next generation level radars.