Ultrawideband Parallel Strip Antennas Designed by Genetic Algorithms

Since the Federal Communications Commission (FCC) approved rules for the commercial use of ultrawideband (UWB) radio applications, UWB antenna structures have been a intensive research field in order to satisfy the spectrum requirements of this technology. Different kind of UWB radiators like monopole and printed single side dipoles have received more attention compared to double side structures. In this paper, a set of different shape antennas fed with parallel-strip transmission lines (UWB-PS antennas) are proposed and studied, taking into account the return losses metric. The geometrical parameters have been computed using a genetic optimizer linked to a method of moment (MoM) simulator like IE3D Zeland. The main advantage of the designed geometries lie in the fact they do not include ground plane, radiating in almost the whole space. Measurements of two candidates with circular and exponential profiles have been carried out, showing a good frequency behaviour in the frequency band from 3.1 GHz to 10.6 GHz.