Design of Cluster Feed Horns of Beam Scanning Lens Antenna

In ITS services, millimeter wave frequency bands are used and antennas are required beam scanning ability. Wide angle scanning can be achieved by introducing Abbe sine condition to lens surface shaping. Authors designed a lens antenna that could achieve beam scanning over plusmn30deg. Narrow beam widths were maintained on the scanning planes. However, beam shapes were distorted on the transverse planes. The reason of this beam distortion was due to the phase delay on the aperture. A phase delay correction was achieved through the radiation pattern synthesis of a cluster feed. In this paper, the cluster feed is composed of a group of rectangular horns that corresponding to the situation of an actual antenna. In order to achieve a phase delay correction, a new radiation pattern synthesis method is developed. Resultant excitation coefficients of the cluster feed horns are shown. And the phase correction in the radiation pattern of this feed is clarified. More over, achievements of excellent beam shapes and antenna gain in the wide angle beam scanning are shown.