Variable circular polarization antenna having parasitic Z-shaped dipole

摘要

A specially designed, Z-shaped, parasitic dipole is spaced radially outwardly from the slot provided in a cylindrical antenna; a controlled amount of energy which is in a horizontally polarized direction is coupled to the Z-shaped dipole so as to radiate energy into the vertical plane, thus creating a variable circularly polarized antenna capable of adding a selectable amount of vertical component to the horizontal in quadrature; since the dipole element, which parasitically develops its polarized energy, is in the same horizontal plane as the polarized energy emanating from the slot, a good, i.e. constant, axial ratio is maintained throughout the elevation pattern.