Leaky Mode Radiation Properties of Dielectric Loaded Helix

In this paper, a full wave analytical theory has been established in order to determine the radiation properties of the dielectric loaded helix (DLH) in leaky mode configurations. The dispersion diagram, which establishes the axial phase propagation constant as a function of frequency, is used to categorize the guided and leaky mode region. By taking into account, electric and magnetic field vector potentials as well as the polarization current approach, the analytical theory of radiation is developed. According to the guided mode's and leaky mode's respective modal dispersion properties, the radiation pattern in end-fire direction and broadside direction is calculated and described. The calculated axial phase constants have been used to identify the electric and magnetic field components at a given frequency, which have then been translated into electric and magnetic field potentials and, ultimately, radiation characteristics. This type of geometry is useful for designing wideband leaky wave antennas.