Abstract
This paper considers the gain performance of a square patch antenna when it is enclosed by complementary forms of either circular or square Electromagnetic Bandgap (EBG) cells. This performance is compared against the square patch antenna with EBG structures in their non-complementary forms. It shows that the use of complementary EBG cells results in a comparatively better gain performance. The study includes a consideration of the groundplane size and the number of rows surrounding the patch, as these could affect the gain performance. Initially, antenna configurations with complementary EBG geometries are simulated to observe the gain enhancements. This is followed by experimental measurements to substantiate the simulation outcome. Simulated and measured reflection coefficients (S 11) and co-polarized radiation patterns are in good agreement.