Measurment of output power of microwave sources using cutoff characteristic of waveguide

The cutoff characteristic of waveguide is theoretically analysed in this paper, as well as the feasibility and accuracy in measuring the output power of HPM using the characteristic. It was used to measure the output microwave power of a magnetically insulated transmission line oscillator(MILO) operating at 1.75 GHz in far-field region. The experimental results show that a 2.3 GW high power microwave of TM01 mode is detected from the MILO device. The detected radiation pattern agrees with that of the simulation well. The microwave pulse width is more than 40 ns, and there is no obvious microwave power breakdown. It is good to use the cutoff characteristic of waveguide to prevent the power breakdown of the receiving horn and improve the measuring accuracy.