Excitation of the Circular Symmetric E-Mode on Dielectric Rods by an Open-ended Waveguide

ABSTRACT

The efficiency of excitation of the lowest order circular symmetric E-mode on dielectric rods is investigated for a circular filament source outside the rod and for an open-ended waveguide launcher. The fields for the latter case are obtained by a superposition of the fields for elementary circular filament sources inside and outside the dielectric region. Calculations of the excitation efficiency in both the cases are presented for various dielectric constants and the normalized dimensions of the launchers. Results point out that for operation near cut-off (i.e. for thin rods) efficiencies higher than 0·80 and 0·50 are obtained by using filament sources and open-ended waveguide launchers respectively.