A HIGH-DIRECTIVITY MICROSTRIP PATCH ANTENNA DESIGN BY USING GENETIC ALGORITHM OPTIMIZATION

Abstract

A high-directivity patch antenna with broadside directiv- ity is attractive, since a narrow beam can be obtained without the need of using an array of antennas. Therefore, the solution becomes simpler as there is no need for a complicated feeding network. In this sense, this paper presents a novel patch antenna design with high directiv- ity in the broadside direction by using genetic algorithms (GA). The proposed GA method divides the overall patch area into difierent cells taking into account that cells have a small overlap area between them. This avoids optimized geometries where cells have only an inflnitesimal connection. Therefore, the proposed method is robust for manufactur- ing. The antenna operates in a higher-order mode at 4.12GHz and the geometry flts inside a patch of 40mm £ 40mm on a substrate with a relative permittivity of 3.38 and a thickness of 1.52mm resulting in a directivity of 10.5dBi. The specialty of this design is the use of GA to select the optimized shape and the feeding position instead of a known shape and a flxed feeding position. The antenna has been fabricated and the simulation results are in good agreement with the measure- ments. This results in a simpler design of a single high-directivity patch, which can substitute an array of two elements operating in the fundamental mode.