The image method of beam shaping

The image scheme of beam shaping for use at microwave frequencies is described. Cosecant-squared radiation patterns are obtained with parabolic reflectors no larger than those required to give pencil beams of commensurate beam widths. Radiation patterns calculated using diffraction theory are compared with measured patterns of a paraboloidal dish fed by a horn feed and one image horn. Experimental patterns are included to show the effects of variation of all parameters. A qualitative analysis of a paraboloid fed by a horn and several images is shown to agree with measured results.