Effect of air breakdown on high power microwave antenna

The high electric field of high power microwave propagating in atmosphere makes air breakdown possible, which confines the maximun transmitting power of microwave antenna because of its intense power density. It is in the near field that the air breakdown often occurs. The power density distributions of rectangle and circular aperture antennae were analyzed and the normalized power density of different aperture distribution was obtained. Based on the air breakdown power density threshold, the maximum transmitting power of circular antenna was given.