On Minimum Range for Radiation Patterns

It is shown that the 2D2/¿ antenna criterion ensures a phase variation less than ¿/8 and an amplitude variation less than 10 per cent over D when using a paraboloidal or optimum horn antenna for illumination, providing its aperture dimensions do not exceed D. The pattern of a uniform line antenna illuminated by such a paraboloid is shown to be essentially the same as its conventional pattern (point source illumination). It is also shown that the appropriate criterion for back scattering patterns is 4D2/¿. earch Foundation.