Ring-like radiation enhancement phenomenon of inhomogeneous plasma layer coated metallic antenna.

Radiation enhancement phenomenon of a thin inhomogeneous plasma layer covered metal antenna can be observed by optimizing the plasma density and electron temperature for giving antenna--plasma layer configuration. Based on the collisional plasma assumption, theoretical results obtained by solving the eigenmode dispersion relation of symmetric waves propagating along the antenna--plasma layer interface indicate that, when the wave frequency is 1 GHz, the radius of the metal antenna is 3 times of the plasma skin depth, and the thickness of the sheath is about one tenth of the thickness of the main plasma layer, there is a ring-like radiation enhancement phenomenon where the plasma frequency is about 1.4 times of the wave frequency. This radiation enhancement phenomenon may induced by the impedance resonance of the antenna-plasma layer configuration, and which may have great potential in radio frequency antenna communication.