Antenna modelling using linear elements, with applications to UWB

It is a convention to place an antenna in the coordinate system in a way that simplifies radiation field expressions. In order to model more complex antenna structures using a combination of basic linear elements, we first describe how three-dimensional radiation field expressions corresponding to an infinitely thin linear antenna change with rotation and translation. Then we decompose a more complex antenna (diamond), which is of particular interest in ultra wideband applications, into combinations of basic linear elements. The effective radiation pattern is a superposition of the radiation patterns corresponding to each of six linear antennas positioned along the edges of the two diamond antenna elements. The radiation patterns predicted by modelling and by simulations match well, when one accounts for frequency-dependent superposition factors and for the continuity of the current where model antenna line elements meet.