High power microwave air breakdown by changing effective aperture of horn antenna

The paper presents a method to get high power microwave gas breakdown by changing the effective aperture of horn antenna. Changing the effective aperture can adjust the electric field near the inner dielectric window, lending to air breakdown. The principle of this method is introduced. In addition, the verification experiment has been carried out for L band microwave with pulse duration being 30 ns, and the experimental waveforms are analyzed. The breakdown threshold of 0.40×105 Pa air was measured to be 33.9 kV/cm. The experimental results agree well with the design, and the method is proved to be effective to study high power microwave gas breakdown.