A QUASI-STATIC THEORY FOR DIELECTRIC-COATED THIN-WIRE ANTENNA STRUCTURES

Analytical investigations of the problem of dielectric- coated thin-wire antenna structures have invariably focused on the physics of developing appropriate models for the dielectric insulation on the thin-wire conductors that serve as antenna for the structure. These include the frequency domain moment-method-based approaches in which the dielectric insulation is replaced by equivalent volume polarization currents; and the time-domain analysis based on the 'equivalent radius' concept. An earlier paper gave a physical interpretation to the frequency-domain solutions to suggest that the volume polarization currents derive from an equivalent static charge distribution, which excites an essentially radially-directed quasi-static fleld, conflned to the region associated with the dielectric insulation. It is the main objective of this paper to investigate the veracity of the claims made in open literature as they concern the physics of the model for the dielectric insulation in terms of the electric fleld excited in the dielectric region. And to that end, simulation experiments were carried out, using a commercial Transmission Line Matrix (TLM) Method code, with which the characteristic features of the radial and axial components of the electric fleld within the dielectric region were investigated. The simulation results obtained from the experiments suggest that the fleld in question is not only of the quasi-static variety, but that it is also characterized by an axial component that meets the