Abstract: An antenna element for radiating electromagnetic signals having a first and a second generally C-shaped groundplane that are formed of conductive material. The groundplanes are connected to one another and define a notch which has one end that is open to free space. An elongated section of transmission line is disposed between the two groundplanes. The transmission line has a source receiving end connectable to a signal source and also has a feed end opposite to the source receiving end. A segment which acts as a transformer is located within the notch. The transformer segment has a first end that is connectable to the feed end of the transmission line and has a second end which faces the notch open end.Preferably, at least one transformer step is located along the transmission line between the source receiving end and the feed end. Also, an open circuit section of transmission line is preferably connected to the transformer segment second end.