Multibeam feedhorn, feed apparatus, and multibeam antenna

摘要

A multibeam primary radiator apparatus (2) includes first, second and third primary horns (16, 18, 20). The first primary horn (16) has a generally circular proximal end aperture (22) at its proximal end, and a generally circular distal end aperture (24) at its distal end, which is larger than the proximal end aperture (22). The second and third primary horns (18, 20) have generally circular proximal end apertures (26, 28) at their proximal ends, and larger distal end apertures (30, 32) at their distal ends. The first through third primary horns are disposed with the center axes of the respective proximal end apertures being substantially in parallel with each other. The distance between the center axis of the first primary horn (16) and each of the second and third primary horns (18, 20) is smaller than the diameter of the proximal end aperture (22) of the first primary horn (16). The distal end aperture (30, 32) of each of the second and third primary horns (18, 20) is formed by a semicircular portion (30a, 32a), which is half of a circle having a diameter larger than the proximal end aperture (26, 28), on the side remote from the first primary horn (16), and also a semi-elliptical portion (30b, 32b), which is half of an ellipse, on the side closer to the first primary horn (16). Each semi-elliptical portion (30b, 32b) is contiguous to the associated semicircular portion (30a, 32a) at the two ends of the major axis thereof, and is located in a void in the distal end aperture (24) of the first primary horn (16). The end of the minor axis of each ellipse is located outward of the proximal end aperture (22) of the first primary horn (16).