A novel structure for extended interaction oscillators operating at 0.3 THz

Abstract

To improve the efficiency of vacuum electron devices operating in the terahertz band, a crossed structure for the extended interaction oscillator (EIO) is proposed. With this structure, the Ez field around the cylindrical beam is more uniform, thereby allowing full use of the electron beam's energy. The characteristic impedance in this crossed configuration is also enhanced compared with those of the traditional one-cavity-EIO of the same size. In optimising the parameters of the crossed EIO, the effects of the beam and the guiding magnetic field on the device's performance were studied. The influences of various lossy materials on the output power were assessed with copper prevailing as best for these terahertz devices because of its high conductivity. Finally, the optimised structure was analysed by particle-in-cell simulations. The conductivity of the used metal was set at , which is around 20% that of pure copper and coincides with practical situations. The results show that for an electron beam of 14 kV and 0.6 A, the device operates stably at a frequency of 318.3 GHz and output power of 14.7 W. The enhanced output results demonstrate the practicality of the crossed configuration for EIO in the terahertz range.