X-band high power microwave mode-selective directional coupler

The development of high power microwave(HPM) technology now trends toward higher power and longer pulse, and overmoded devices are employed to increase the power handling capacity of HPM sources. In order to discriminate the dominant TM01 mode of an X-band long-pulse overmoded HPM source, a mode-selective directional coupler with stable coupling coefficient, high directivity and high power handling capacity in wide band is numerically investigated. At the central frequency range of 9.2-9.6 GHz, the simulation results show that the coupling coefficient is -54 dB, the directivity of TM01 mode is more than 35 dB, the suppression of TM02 mode is about 15 dB, and the power handling capacity is 3 GW.