Enhanced Radiation Beams from Three Annular Plasma Layers Coaxial Line Excitation

Abstract

This study is concerned with the radiation pattern of an open-ended co-axial line excited in TEM mode in three annular plasma layers having central conductor along its axis. The field distribution at the open-end cross-section of the co-axial line is assumed to be equivalent to the vector sum of magnetic current rings of various radii, ranging from the outer radius of the inner conductor to the inner radius of the outer conductor of the co-axial line at the open-end. The radiation field is obtained as a vector sum of field components due to individual rings of magnetic current. This type of configuration gives rise to a well enhanceed radiation beams beyond the critical angle sin2θcc=ε) corresponding to the plasma layer having the least relative dielectric constant. The directions of these radiation beams can be changed by changing the plasma density.