A comparative study on the parabolic and spherical FPA-fed reflector antenna

Focal and axial fields of the parabolic and spherical quasi-optical antenna systems are analyzed. The effects of axially displaced focal plane array (FPA) in both systems were investigated. The axially displaced FPA-fed parabolic reflector can broaden the field patterns across the FPA. FPA-fed spherical reflector if carefully tuned along its paraxial line can broaden the field patterns across the FPA as well. The broadening in both systems can results in a larger reuse of the antenna elements in the FPA during beam scanning, hence a smaller FPA size can be utilized. The advantage of the FPA size reduction is that it can reduce the complexity of the FPA feeding-lines and chip-sets integration.