Printed UWB antenna for portable devices

The shape of the radiator of an UWB antenna has a very strong effect to the impedance bandwidth of the antenna. This paper showed that the -10 dB bandwidth of an UWB antenna can be increased even 60 % using elliptical edges instead of straight edges in the radiator and without increasing the largest dimensions of the radiator. Is was also shown that the size of the radiator and the ground plane clearance can be reduced by covering the radiator with a dielectric superstrate. The size reduction of an UWB antenna operating at European UWB frequency range from 6.0 to 8.5 GHz was 31.6% for the radiator and 30.6% for the ground plane clearance. This means considerable space saving in portable device point of view, where space is very precious.