Microwave breakdown of antenna radomes at high altitudes

Abstract

This paper presents data obtained from experimental measurements of antenna-radome breakdown using pulsed power at X-band frequencies and compares the results with those predicted by analysis. Parameters that were investigated experimentally are: antenna dimensions, radome depth, radome material, pulse width, pulse repetition frequency and pressure. The equivalent diffusion lengths calculated from the measured breakdown data depend on these parameters in a manner which has been incorporated into the theoretical analysis. Furthermore, it has been observed that the antenna breakdown power drops off sharply above a certain critical pulse repetition frequency. This behaviour is attributed to an increasing radome surface charge which is also taken into account in the analysis. The breakdown data have been reduced to generalized radome breakdown curves which permit the breakdown conditions to be determined for a wide range of parameters. The effects of a plasma sheath surrounding the antenna radome are briefly discussed and scaling laws appropriate to antenna-radome breakdown are outlined.