Patent ID: 6320553
Filing Date: 2001-11-20
Classification: H01Q

Abstract:
An antenna structure comprising:a parabolic reflector having a focal region;an ellipsoidal subreflector having real and virtual focal points and a dichroic surface, said subreflector being positioned at the focal region of said parabolic reflector in a Gregorian arrangement;a phased array antenna feed integral with said subreflector and operating in a mid-frequency band, said phased array antenna feed being capable of illuminating said parabolic reflector and including means for correcting for defocusing aberrations, said dichroic surface being transparent to energy in mid-frequency band;a linear antenna feed operating in high frequency band, said linear feed capable of illuminating said parabolic reflector, said linear feed being positioned in the illumination path of said phased array feed passing through the real focal point generally along a line connecting the real and virtual focal points, thereby reducing mutual blockage between the illumination from said linear feed and said phased array antenna feed; anda hybrid mode antenna feed operating in a low frequency band, said hybrid mode antenna feed being capable of illuminating said subreflector and being positioned at a point adjacent the virtual focal point of said subreflector.