Output characteristics of the high-power microwave generated from a coaxial vircator with a bar reflector in a drift region

Numerical simulation studies of a coaxial virtual cathode oscillator with and without a bar reflector have been performed by the three-dimensional particle-in-cell (PIC) code, MAGIC. Also, the experimental studies are performed in our high-power microwave pulser, "Chundoong" to compare with numerical results. It consists of a cylindrical anode-mesh, a coaxial type cathode, and a bar reflector. Results show that the output microwave mode without a reflector is shown to be a mixture of TE and TM modes and the output microwave frequency has a narrow bandwidth and a main frequency is about 3.38 GHz from a coaxial vircator without a bar reflector. But the TM01 mode with its frequency of 3.34 GHz is shown to be dominant for the coaxial vircator with a bar reflector. It is found in this experiment that the output microwave power sensitively depends upon the position of a bar reflector.