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AN EXPERIMENTAL STUDY OF PLASMA SHEATH EFFECTS ON ANTENNAS
ARIZONA UNIV TUCSON ENGINEERING RESEARCH LABS
A plasma simulation technique was developed which can be used to study the effects of homogeneous or inhomogeneous plasma sheath on the radiation pattern deterioration and input impedance of microwave antennas. A tank was designed and constructed for use in the simulation technique which can reproduce by means of real dielectric materials the dielectric constant encountered in plasma covered antenna research. The radiation patterns and the input impedances of an annular slot and a thin and long rectangular slot have been successfully measured in the presence of a simulated loss-less, homogeneous and isotropic plasma layer of varied thickness. Comparison with the available theoretical data indicates a generally good agreement, although some differences exist. In the case of the radiation patterns these differences are attributed to the finite distance between the radiator and the receiving antenna on one hand and the inherent inaccuracy of the saddle point method of integration in certain regions on the other hand.
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