Radiation pattern of high power microwave from axially extracted virtual cathode oscillator

摘要

We have investigated a radiation pattern of high power microwave from an axially extracted virtual cathode oscillator (vircator) by adoption a horn-type transmitting antenna at the downstream end of waveguide in this experiment. This high power microwave generator is powered by the "Chundoong" intense relativistic electron beam pulser (Max 600 W, 88 kA and 60 ns duration). The 3 kinds of receiving horn antenna, WR 187, WR 137, and WR 90 have been alternatively used in this experiment to determine the high power microwave frequency. The receiving antenna has been located at 1 meter distance away from the transmitter antenna surface, where the angle of their respective receiving antenna has been varied to be 10/spl deg/ up to 90/spl deg/ in both horizontal and vertical directions along their respective arcs to measure a directivity of axially extracted high power microwave in free space propagating from transmitter antenna. It is found for high power microwave from axially extracted vircator that both horizontal and vertical radiation pattern have good directivity with plateau characteristics within 20/spl deg/ with respect to their 0/spl deg/ reference planes. It, is also noted that the maximum microwave power and its frequency are measured to be 200 MW and 67 GHz, respectively, under diode voltage of 300 kV and diode current of 25 kA.