8 Mm Band Coaxial Extended Interaction Oscillator Research

The millimeter wave refers to electromagnetic wave which has an operating frequency ranging from26.5-300GHz. Due to its several advantages, such as wide frequency band and narrow beam, it has an attractive prospect in both military and civil field, and now is a very active research area in the world. The extended interaction device is a major category of millimeter-wave electronic vacuum tube. The study found that the extended interaction oscillator (EIO) is well suited to work in the millimeter wave band, and now becomes one important type of High power millimeter-wave devices. This dissertation which is funded by the National Natural Science foundation of China, has conducted an in depth research on the extended interaction oscillator. The major achievements are listed as follows:1. The EIO with inner and outer disk loaded coaxial waveguide slow-wave structures(SWS)is studied in the paper:The dispersion equation of the SWS is derived according to the non-uniform theory of the cylindrical loaded mode waveguide. The numerical analysis is carried out, and the dispersion curves and the SWS structure parameters of8mm wave band are gotten.2. The high frequency system of the millimeter wave EIO with two section of the inner and outer disk loaded coaxial waveguide SWS is designed. The high frequency system is simulated by the2.5-dimensional full electromagnetic model MAGIC software. The basic physical process of the beam-wave interaction is observed, and the structure parameters, the beam parameters, and the magnetic field parameters which will effect on output power are analyzed. A set of optimum parameters is gained.3. The planar electrode shape of the Kano long-barrelled electron gun is calculated according to the theory of space-charge flow in the Kano plane and the symmetric electrode shape is deduced according to the cathode surface electric field matching calculation method. The electrode parameters of the electron gun is simulated and optimized by MAGIC software. The Toroidal electron gun which satisfies the high frequency system requirements is obtained.4. Based on the operation control indicators of our laboratory, the particle simulation method is used to investigate the whole-tube properties of the coaxial EIO, which the high-frequency system and toroidal electron gun. The results show that, when the axial guide magnetic field is0.5T, this device can generate continuous wave output power of14.5kW in8mm wave band with a good spectrum.