Increasing the directivity of a microstrip patch array by genetic optimization

Conventional single element microstrip patch antennae have a low directivity (6-8 dB). In order to increase the directivity, an array of microstrip patches can be used. It may be possible to further improve the performance of arrays by applying genetic algorithms (GA). This paper presents a method to increase the directivity of a 2 × 1 patch array with broadside radiation using GA. The proposed GA method divides the patch area into different cells, taking into account that cells have a small overlap area between them. The patch array is etched on a substrate with a relative permittivity of 3.38 and a thickness of 1.52 mm. The antenna operates at 4 GHz resulting in a directivity of 10.9 dB. The specialty of this design is the use of GA to select the inter-element spacing, optimized shape and the feeding position instead of a known shape and a fixed inset length of feeding. The results show that the directivity of the genetic array is larger than that of the conventional array with the same overall dimensions, which resonates at the same frequency.