Radiation patterns of a log-periodic antenna in the VHF band: comparison between simulations and measurements

The aim of this paper is to compare the output of two models used to determine the radiation patterns of log-periodic antennas placed over a ground plane, with measurements performed in the VHF band. In the first part, we describe the simulation models: the reflection coefficient method based on the moment method, and the R/sub V//R/sub H/ method, based on the Fresnel reflection coefficients. In the second part, we present the method used to measure the radiation patterns. These measurements were realized at several frequencies and several antenna heights. Then, we compare the experimental and the simulated results and we conclude with the capabilities of each model.