Voltage breakdown characteristics of microwave antennas

At low pressures, antennas are susceptible to voltage breakdown. In the case of missiles, for example, there are indications that very low power is sufficient to initiate and maintain breakdown. Since it is essential that the system performance is not interrupted for high-altitude operation, an experimental investigation has been made to study the properties of antennas under breakdown conditions. When voltage breakdown occurs, the effect is fourfold: the input impedance is altered, the total radiated power is decreased, the radiation pattern is changed and the pulse shape is distorted. The effect on these properties of input power level, pulse width, pulse repetition rate, and pressure is discussed.