Design of a compact and low-cost fractal-based UWB PCB antenna

In this paper, two compact PCB antennas operable over the ultra-wideband frequency range are presented. Both designs feature a 1.6-mm-thick substrate based on the low-cost FR4 epoxy material, a microstrip-line feed with a matching section, a patch that efficiently uses the available substrate´s surface, and an optimized partial ground plane comprising a rectangular and a semicircular part. The second antenna is a modified version of the first, basically obtained by rounding the corners of a rectangular patch and using fractal geometry in its construction. These modifications lead to better return loss values and an improved UWB bandwidth. FEM- and MoM-based EM packages were used to simulate and compare the two designs. Both yielded omnidirectional radiation patterns and good gain and efficiency figures, over the bands of operation.