A broadband rolled edged cavity antenna

A cavity antenna has been developed to feed a small reflector antenna efficiently over a relatively wide bandwidth. Efficient antenna feeds for reflector antennas generally require rotationally symmetric, low sidelobe patterns. The novel cavity antenna has a broadband crossed dipole and a rolled edge cavity termination to reduce illumination loss resulting from feed backlobes. The design is motivated by a future GPS monitoring application covering the L5 (1186 MHz) to L1 (1575 MHz) frequencies. The compact feed reduces blockage in a relatively small (4 ft) reflector. Analyses and validating measurements are presented.