Patent ID: 6181289
Filing Date: 2001-01-30
Classification: H01Q

Abstract:
A multibeam antenna reflector having a reflection surface expressed by a combination of at least first and second corrected surface functions, wherein:in a coordinate system defined by an X1 axis horizontally extending across an aperture of said reflector, a Y1 axis vertically extending across said aperture, and a Z1 axis extending perpendicularly to said X1 and Y1 axes, said first corrected surface function is expressed byz1=[-(x1.sup.2 +y1.sup.2)/4(F1+g(x1, y1))]+F1where g(x1, y1) is expressed by k1(y1+.alpha.)+k2(.vertline.x1.vertline.+.beta.), (being a value not smaller than -(of +D) and not greater than (of +D), .beta. being a value not smaller than -D/2 and not greater than D/2, of being an offset amount of said reflector which is not smaller than 0, D being a diameter of a circle resulting from projecting a desired area of said first corrected surface function onto the X1-Y1 plane, F1 being a focal length of said first corrected surface finction, k1 and k2 being coefficients;in a coordinate system defined by an X2 axis horizontally extending across an aperture of said reflector, a Y2 axis vertically extending across said aperture, and a Z2 axis extending perpendicularly to said X2 and Y2 axes, said second corrected surface function is expressed byz2-[-(x2.sup.2 +y2.sup.2)/4(F2+g(x2, y2))]+F2where g(x2, y2) is expressed by k1(y2+.alpha.)+k2(.vertline.x2.vertline.+.beta.), .alpha. being a value not smaller than -(of +D) and not greater than (of+D), .beta. being a value not smaller than -D/2 and not greater than D/2, of being an offset amount of said reflector which is not smaller than 0, D being a diameter of a circle resulting from projecting a desired area of said second corrected surface function onto the X2-Y2 plane, F2 being a focal length of said second corrected surface function, k1 and k2 being coefficients;said reflection surface ties in a combined area provided by weighting and averaging said first and second corrected surface functions with said Z1 and Z2 axes being disposed in parallel with respective directions in which at least two electromagnetic waves propagate, andfocal points of first and second corrected surface functions are determined such that coordinate values of said first and second corrected surface functions at the center of said combined area are the same and normals of said first and second corrected surface functions at the center of said combined area are aligned.