High gain, low side lobe dual reflector microwave antenna

摘要

A significant problem in rotationally symmetric dual reflector systems is the blockage caused by the sub-reflector. This blockage produces lower gain and higher side lobes. The invention disclosed herein can be used to minimize or eliminate the blockage effects. In its simplest form, the invention is to place a hole in the sub-reflector. This allows radiation to by-pass the main reflector and replaces the radiation which is blocked by the sub-reflector. In general this radiation and the radiation which progresses on the standard path, which includes the main reflector, will not be in a useful phase and amplitude relationship. However by appropriate design of the inner and outer sub-reflector surfaces, the main reflector surface, the feed aperture, the dielectric support and the possible use of a dielectric rod, the phase and amplitude relationships can be controlled. The invention also applies to cylindrical dual reflector systems which are symmetric about a plane.