Optimization of the geometry of a TEM-horn for radiation of ultrashort pulses used as an element of an antenna array with controlled position of the main lobe

The finite-difference time-domain method is used to build the model of a TEM-horn with exponential longitudinal distribution of the characteristic impedance along the axis. This model is used to calculate the antenna energy pattern and the shape of the ultrashort pulse of the electromagnetic field in the far zone. Geometrical parameters of the antenna aperture are selected so as to increase the width and the uniformity of the energy pattern in the direction of radiation as well as minimize the level of the backward radiation.