Breakdown in a high power microwave antenna

In this work, a high power microwave (HPM) antenna is designed and its breakdown limits are investigated. It has been shown that the designed antenna can handle Giga Watt (GW) power without attaining breakdown. The flash-over which usually occurs at the interface of HPM antennas, where microwave leaves and enters into the air, was controlled by adjusting the field intensity at the output window of the antenna. It has been shown that by adopting Gaussian beam distribution at the aperture of horn with appropriate beam waist, the E-field intensity at the output window can be reduced significantly. It has also been demonstrated that an HPM antenna with 0.4 m aperture radius can sustain >30 GW power for a pulse duration of 1ns and the same is reduced to <5 GW for the pulse having duration > 1μs.