Study of Thermal Noise Generated in a Vivaldi Antenna Using the Improved Wheeler Cap Method

We analyze sources of inefficiency in a single Vivaldi antenna. The analysis is based on simulations of antenna radiation efficiencies and measurement data obtained via the Improved Wheeler Cap (IWC) method. The accuracy of the IWC method is established in full-wave simulation (HFSS) by comparison to metal loss computation in method-of-moment simulation (FEKO) and efficiency calculation of a lossless Vivaldi antenna. These results suggest reliability of the IWC method. The method is then used to investigate sources of losses in the antenna.