Axially Extracted Virtual Cathode Oscillator with Annular Cathode

A numerical simulation study of a virtual cathode oscillator withannular cathode has been performed by a 3 dimensionalparticle-in-cell (PIC) code called MAGIC. Also the experimentalstudies are performed for comparison of numerical results. Theannular diode consists of circular anode mesh and annular typecathode. The object for this investigation is to find theoptimized width and radius of the annular cathode in our highpower microwave pulser, “Chundoong". Both of simulation andexperimental results show that the output microwave power andfrequency depend on emission width and radius of annular cathode, and the dominant mode of output microwave is TM01 under theoptimized width 4 mm and radius of 20 mm.