Experimental investigation of a plasma covered, axially slotted cylinder antenna

A discharge tube and facility for measuring the equatorial patterns of an axial slot antenna on a plasma covered cylinder are described. A Langmuir probe survey of the tube is made to determine axial, radial, and azimuthal variations of electron density. Experimental patterns made at various concentrations of electron density are obtained which closely resemble theoretical patterns for
\nu/\omega \cong 0.16
. Absorption and dipole resonance predicted to occur at (
\omega_{p}/\omega)^{2} \simeq 1
and 1.8, respectively, are experimentally observed.