Direct PO optimized dual-offset reflector antennas for small Earth stations and for millimeter wave atmospheric sensors

An efficient direct numerical synthesis method for dual offset reflector antennas which is directly based on the physical optics procedure for both reflectors (PO-PO-method) and where the reflector surfaces are advantageously characterized in the spatial domain by a 2D Fourier-transformation is described. The method uses an evolution-type optimization algorithm to shape both reflectors simultaneously so as to generate the desired far field with prescribed criteria. The efficiency of the design method is demonstrated for two computer-optimized dual-offset antenna designs for space applications, a very compact optimum shaped Gregorian Earth station antenna with high offset angle (70°) and small subreflector size (13 λ) and a shaped Cassegrain atmospheric sensor antenna for 200 GHz. The theory is verified by available measured results