Subreflector near-field patterns in the “s” coordinate system as a function of angle θ_s from the ellipsoid axis z_s, in half-planes with different values of φ_s: φ_s = −90°, red; 0°, green; 90°, blue. Vertical lines indicate the near edge (), center (), and far edge () of the main reflector in the φ = −90° half-plane.