Multiple reflector antenna

Claim 1

A multiple reflector antenna comprising: a main reflector formed of a portion of rotatively symmetrical surface with respect to a rotation axis, a sub-reflector, at least one auxiliary reflector, and at least one wave source; said axis being so constructed as to be parallel to or slightly deviated from the antenna aperture plane, and characterized in that said sub-reflector and auxiliary reflector are designed by the following procedure: first a coordinate system having its origin on the aperture surface is defined, and next a vector S representing a path from said origin to a point on said sub-reflector and a vector B representing a path from said origin to a point on said auxiliary reflector are defined, said vectors B and S being given by equations (1) and (2) below, function f(θ, φ) included in said equations (1) and (2) is substantially determined by the solution of extremal value problem of a functional which is related to a function f(θ, φ) representing a difference between a desired value and the actual value of the aperture field distribution at said antenna aperture plane, ##EQU13## S=B+[l.sub.O -λ.sub.A -λ.sub.M -f(θ,φ)]R.sub.B ( 2) where ##EQU14## where, FO is a vector of a path from the origin to the focus of the feed horn, θ and φ are, respectively, zenith angle and azimuth angle in a polar coordinates with its center at the focus of the feed horn and zenith direction toward the center of the auxiliary reflector, β is an angle between the zenith axis of said polar coordinates and the wave path from said main reflector to the aperture plane, l o is the length of wave path from wave source through auxiliary reflector, sub-reflector and main reflector to the antenna aperture plane, λ M is the wave path from the sub-reflector to the main reflector, and λ A is the wave path from the main reflector to the antenna aperture plane.