An Estimate of the Effect of Forced Convection on Antenna Breakdown and Slotted Antennas

摘要

The equation for conservation of electron number density is used to calculate the number density growth rate for a gas flowing over a conducting ground plane past a slot antenna. When used with a breakdown condition, this growth rate implies a breakdown voltage. The second term of a series solution shows the reduction of time that an electron is in the exciting electric field. Since the electrons are convected through the exciting electric field, the breakdown acts as if the electric field were pulsed, even when it is on continuously. As a consequence, the pulse time used to calculate the first term breakdown is either the pulse duration or the 'effective transit time', whichever is shorter. Another effect of forced convection is to increase the concentration of electrons near the wall, which improves the coupling between the electrons and the nonuniform electric field outside the slot antenna, thereby initially reducing the breakdown voltage. (Author)