Analysis of monopole antenna excited by a current probe

This paper presents a study of monopole antenna at high frequency (HF) band for wireless communications. The traditional monopole antenna is commonly excited using the electric probe feed method. In this paper, the current probe excitation method is presented. A current probe which consists of a ferrite coil with N turns is used to induce current into the monopole antenna. In order to optimize and understand the ferrite coil of the current probe, an analysis of the characteristics of the ferrite coil is presented. Parameters such as the outer radius, core radius and relative permeability of the ferrite coil, are varied and results are presented and analyzed. Results show that in order to maximize current coupling from the current probe to the antenna, the outer radius of the ferrite core should be small and the core radius should be thick. Relative permeability has little effect as long as it is sufficiently large.