Low sidelobe reflector design using resistive surfaces

Low-sidelobe amplitude distributions for rotationally symmetric reflectors are obtained by varying the reflection coefficient as a function of the radial distance. The required reflection coefficient is calculated by comparing the geometrical optics (GO) current to the desired aperture taper (e.g., Taylor). If the normalized GO current at every point on the surface is greater then the normalized design taper, the required reflection coefficient will be less than one, and the GO current can be corrected with a resistive surface. This provides a means of fine tuning the amplitude distribution, something that cannot be accomplished entirely by feed shaping.<>