A
design process first determines a desired aperture distribution, then converts the
electric power conservation law, Snell's law on the rear face side of a
dielectric lens, and the formula representing light-path-length constraint, into
simultaneous equations, and computes the shapes of the surface and rear face of the
dielectric lens depending on the azimuthal angle θ of a primary
ray from the focal point of the
dielectric lens to the rear face of the
dielectric lens, and then reduces the light
path length in the formula showing light-path-length constraint by an integral multiple of the
wavelength when the coordinates on the surface of the
dielectric lens reach a predetermined restriction thickness position. A
dielectric lens is designed by sequentially changing the lazimuthal angle θ from its initial value, and also repeating the second and third steps. Thus, downsizing and quantification is realized by
zoning while keeping antenna properties at the time of constituting a dielectric lens antenna in a good condition.