Synthesis of axisymmetric shaped dielectric dome antennas with shaped beams at 60 GHz

We investigate here the potentialities of shaped dielectric dome antennas for shaped beam applications at millimetre waves. To this end, we firstly describe the synthesis methodology that has been implemented for the design of any kind of multi-shell / multi-material dome antennas of arbitrary shapes. The design procedure consists in a Genetic Algorithm (GA) combined with an asymptotic method of analysis based on the Geometrical Optics / Physical Optics (GO/PO) technique. The main characteristics of this CAD tool are presented and discussed (representation of the dielectric interfaces and coding, convergence of the algorithm, etc.). Then, two axis-symmetric domes made in Rexolite are designed at 60 GHz. The first one radiates a secant-squared beam for indoor radio coverage with constant illumination. The second prototype produces a pencil beam with a Gaussian shape. In this case, it is shown that optimizing simultaneously the dome interfaces and the dimensions of the feed horn aperture allows improving significantly the radiation performance of the antenna.