FDTD design of a Chinese hat feed tor shallow mm-wave reflector antennas

Relationally symmetric reflectors with hat feeds are attractive for radio link applications in tlx: mm-wave band due to their low sidelobes, simple rotationally symmetric structure and low manufacture cost. The standard hat feed has its best performance in a very deep reflector. In this paper, the V2D computer code based on the finite-difference time-domain (FDTD) method is applied to the analysis of a Chinese hat feed, which is optimized for use in a more shallow reflector. The FDTD results have been post processed to obtain the different subefficiencies characterizing spillover, polarization, illumination and phase losses.