Antenna pattern distortion by dielectric sheets

The radiation pattern of an antenna covered with a radome can be determined from the following data: The antenna Fresnel-Zone fields in the absence of the radome, and the fields inside the radome produced by a plane-wave incident from an external source. In certain cases the pattern calculations may be simplified without excessive loss of accuracy by using optical theory to describe approximately the plane-wave transmission through the radome, and neglecting scattering by the antenna in determining the fields inside the radome from the external plane-wave source.