Size Reduction of Dielectric-Loaded Horn Antennas Combining a Body-of-Revolution (BoR) - FDTD solver and a Genetic Algorithm (GA)

摘要

Wireless access and wireless LANs that will operate in the 60-GHz band have been more and more studied. Depending on the selected communication scenarii [1], various antenna specifications and technologies have been considered for multi-beam and beam-shaping radio coverages, including planar (e.g. antenna arrays and Butler matrices) and 3-D designs. In the 3-D case, reflector [2] and [3,4] lens antenna technologies are promising due to their low-cost, low-weight and attractive performance. In this paper, we study an alternative technology based on 60-GHz dielectric loaded horn antennas, as recently suggested by Holzman [5]. The typical antenna configuration is depicted in Fig. 1. It consists of a conical horn excited by a cylindrical waveguide and loaded by an axis-symmetric dielectric lens. The lens acts as a phase correction device in order to minimize the phase distortion in the horn aperture (especially when the flare angle 2ψ is large), and thus enhance the antenna directivity. In contrast to Ref. [5], the aim of our work is to design much more compact horns (O{sub}(HORN)=4×λ{sub}0) with the highest directivity as possible. To this end, we suggest to shape the lens. Due to the small lens size, the geometrical optics principles cannot be applied securely. Therefore, we propose to design the phase correction lens with the help of a full-wave optimization tool based on the combination between a Body-of-Revolution (BoR)-FDTD solver and a Genetic Algorithm (GA). We first present the main capabilities of this CAD tool. Then various numerical resuts are given. In particular, it is shown that shaping the lens profile provides better results than conventional hyperbolic lenses [5].