Wideband monopole Vivaldi antenna and its angular periodic performance

This paper presents a Vivaldi antenna structure and a study of its performance in an angular perspective over a wide frequency range. A conventional Vivaldi antenna is a structure with two halves creating a tapered open ended slot. Here the conventional Vivaldi is halved with a ground plane and thus the structure become as a monopole. The single monopole antenna is studied and it is compared with an array of two Vivaldis. The simulations results are presented in terms input impedance with different angular periodic values. The radiation patterns are presented with one and two Vivaldis at 1, 3 and 5 GHz based on results of the maximum gain in boresight. Also surface current distributions of a single Vivaldi are presented in the aforementioned frequencies. To steer the beams, a simple method to obtain main lobes in 22.5° angular steps is presented by exciting only one or two antenna ports.