Ga-based design of artificial magnetic ground planes (AMGS) utilizing frequency-selective surfaces for bandwidth enhancement of microstrip antennas

In this paper, we present a novel approach to improving the bandwidth of microstrip antennas using,frequency-selective surfaces (FSSs) as an artificial magnetic ground plane (AMG). The micro-genetic algorithm (MGA) is employed to derive an optimal FSS element configuration that achieves the zero-phase condition,for the reflection coefficient of an artificial surface at the desired frequency band. Two AMG configurations for single- and tri-band applications are designed by using the MGA, and their performances are compared with those of PEC ground-plane cases after integrating the AMGs with microstrip antennas. It is demonstrated that the use of such a surface, in lieu of the conventional PEC ground plane, leads to (in improvement in the bandwidth of planar antennas that are placed above the surface. (C) 2004 Wiley Periodicals, Inc.