On the Performance of Tree-Based Antennas for SLF-VLF Signal Reception

Abstract

A full-wave electromagnetic simulation and experimental study is carried out to explore the effects of tree-induced dielectric loading on the receiving properties of an electrically small, earth-grounded wire monopole. It is demonstrated that by connecting the upper end of the wire to the tree trunk, the input impedance and current distribution of the monopole can be significantly transformed, leading to an enhancement in the received signal strength that becomes more noticeable as the frequency is decreased; for example, at the lowest frequency considered, it is seen that the tree-loaded antenna can increase the received voltage by over 40 dB, when compared to the case without tree loading. An application of the tree-based antenna for low-frequency power line signal monitoring is presented. Overall, simulation results for the input impedance and received signal response are in good agreement with measurement data.INDEX TERMS Electrically small antenna, full-wave analysis, industrial-scale equipment monitoring, lowfrequency radiation, method-of-moments antenna simulation, monopole antenna, power line emission, treebased antenna.