A Novel Horn Radiator With High Aperture Efficiency and Low Cross-Polarization and Applications in Arrays and Multibeam Reflector Antennas

Abstract

A step horn structure is presented that yields about 90% aperture efficiency with low cross-polar radiation. It is found that for obtaining high aperture efficiency, the horn aperture should consist of only the TE type of modes in appropriate amplitudes and phases. The desired TE modes are produced using multiple steps in the horn walls. The distances between the steps are critical to suppress the undesired TM modes. Radiation characteristics of high efficiency circular and square horns are presented and potential applications of such high efficiency horns are discussed.

Genetic Algorithm Optimization of High-Efficiency Wide-Band Multimodal Square Horns for Discrete Lenses

“…The second horn structure (4λ 0 × 4λ 0 ) has an aperture efficiency better than 84% all over the band with a maximum one of 90.72%. Both horns present better electromagnetic performances than the equivalent one with abrupt discontinuities presented in [14] and, even more important, shows an efficiency which has smaller variations over the band of interest. The price to pay lies in the relatively longer horn attained, as Fig.…”

“…As a first test case for the geometry and optimization technique, a horn structure with a 3λ 0 × 3λ 0 aperture and one with a 4λ 0 × 4λ 0 aperture are considered so as to compare with results in [14]. The normalized dimensions, with respect to the wavelength, obtained from the optimization process are presented on Table 2.…”

“…A very interesting dual-polarization high aperture efficiency square horn is that presented in [14]. This soft horn structure allows for an 85% to 90% aperture efficiency and a cross-polarization lower than 25 dB.…”

“…This soft horn structure allows for an 85% to 90% aperture efficiency and a cross-polarization lower than 25 dB. The creation of the desired higher order mode, and the suppression of the undesired, is controlled in [14] via the two abrupt step discontinuities, (Fig. 2).…”

“…As already mentioned, the geometry in [14] is inherently narrow band, since it relies on the distance between the two abrupt discontinuities to cancel out undesired modes. To attain better performance on a wider band we will resort in this paper to slope only discontinuities, which allows for a softer transition and birth of desired modes (Fig.…”