New hat feed for reflector antennas realised without dielectrics for reducing manufacturing cost and improving reflection coefficient

This study presents a new hat feed that is made entirely of metal without using dielectric material. Compared to previous hat feeds where a piece of dielectric is used to support the hat on the waveguide, the new feed has lower manufacturing cost and higher reliability. In addition, the new hat feed has low radiation along the feeding waveguide, which makes the vertex plate unnecessary. Therefore the bandwidth over which the reflection coefficient magnitude is below -15 dB has increased. The feed has been optimised using a genetic algorithm. A prototype has been manufactured, and measured results are presented to verify the numerical simulations.