The Radiation Field of a Magnetic Dipole Antenna in a Conical Sheath

摘要

The radiation pattern of a magnetic dipole antenna that is situated on the axis of a cone of finite conductivity, such as a conical plasma sheath, has been calculated. The analysis makes use of Green's functions in terms of which an integral equation is set up for the induced current distribution in the conical sheath. This integral equation is then solved by a perturbation technique that is based upon the assumption that the sheath is highly reflect¬ing. Finally, the current distribution calculated in this way is used as a source to obtain the far-field radiation pattern. In the case of a 10 degree cone and a wavelength of 2Π times the distance between the antenna and the apex, this pattern exhibits lobes at 60 and 130 degrees from the conical axis.