The curved passive reflector

The curved passive reflector is analyzed theoretically by the aperture-field method and the results are presented in the form of gain characteristics and radiation patterns. It is seen that curving the reflector produces a focusing effect in addition to the basic diffraction phenomenon, thereby providing increased gain as compared with the flat reflector. The limiting value for the flat reflector gain is 6 db while the gain of the curved reflector increases continually with reflector size when properly illuminated. Radiation patterns are computed and it is shown that the effect of reducing tower height is to widen the main lobe and to move the side lobes outward and depress them. It is concluded that, in general, the curved reflector causes lower side lobes than the flat reflector. The dish illumination is shown to be relatively unimportant with respect to the total antenna gain but the side lobe levels are reduced when the dish illumination is made more uniform.