Antenna Beamwidth Control [Antenna Designer´s Notebook]

Some methods for controlling antenna beamwidth are briefly proposed for aperture widths approximately equal to one wavelength. They can be used as primary feeds to create fan beams for radar antennas. The mouth modifications can improve the radiation patterns and the matching of the input impedance. This allows narrowing the radiation pattern, and therefore increasing the gain. On the other hand, similar modifications are advantageous for dual orthogonal polarization or octave-frequency-bandwidth operations of aperture antennas, such as horns. The proposed modifications have been performed for a hoghorn antenna. The measurements of the conventional and modified hoghorn designs are compared in detail.