Radiation patterns of a slot antenna in the presence of a breakdown sheath

The experimental radiation patterns are measured for a
0.4\times0.9
-inch slot antenna in the presence of aperture breakdown over a wide range of gas pressures and breakdown power levels. It was found that pattern distortion caused by the breakdown plasma was not very significant. The overall signal attenuation, however, could be extremely severe, particularly below 0.5 torr.