Radiation characteristics of short backfire antennas

The backfire antenna is a compact antenna with good radiation pattern characteristics. The performance compares favourably with horns but the structure of the antenna is much shorter. Applications are as a feed for a reflector or as a single antenna for mobile communications or as an array element. The backfire antenna operates in a resonant mode. This means that no simple theories to predict performance are available and most design data has been obtained from experimental models. The paper reports a study of the short backfire antenna using the finite difference time domain (FD-TD) technique. FD-TD is a powerful computational technique which has enabled a parametric study of the geometry of the antenna to be undertaken. The theory has been verified by an experimental model. >