Patent ID: 6747604
Filing Date: 2004-06-08
Classification: H01Q

Abstract:
A steerable antenna for allowing transmission of an electromagnetic signal between a fixed feed source or image thereof and a target moving within an antenna coverage region, said electromagnetic signal having a gain varying with the position of said target within said coverage region according to a predetermined signal gain profile thereacross, said coverage region defining a region peripheral edge, said antenna comprising:a reflector defining a reflector surface for reflecting said electromagnetic signal between said feed source or image thereof and said target, said reflector surface defining a focal point, a reflector center point and a reflector normal axis substantially perpendicular to said reflector surface at said reflector center point, said reflector center point and said focal point being spaced relative to each other by a focal point-to-center point distance, said reflector center point and said feed source or image thereof being spaced relative to each other by a feed-to-center point distance along a feed axis, said feed-to-center point distance being substantially equal to said focal point-to-center point distance, said reflector normal axis and said feed axis defining a common offset plane; a first rotating means for rotating said reflector about a rotation axis extending generally perpendicularly from said offset plane in a position generally adjacent said reflector center point so that said antenna provides a nominal signal gain profile over said coverage region, said reflector defining a reference position wherein said focal point substantially intersects said feed axis and corresponding to a nominal signal gain being substantially maximum with said electromagnetic signal substantially pointing at said region peripheral edge; and a gain altering means for altering said nominal signal gain profile so that the latter matches said predetermined signal gain profile; whereby said reflector in combination with said gain altering means are rotatable about said rotation axis so as to steer said electromagnetic signal according to said predetermined signal gain profile at said target moving across said coverage region.