Research On Miniaturization Cold Cathode Electron Gun Based On Carbon Nanotubes

Microwave vacuum electron device is the only choice in the field of high power and high frequency. But the use of thermionic cathode has suffered many limitations. The birth of Vacuum microelectronics(VME) brings vitality and fresh blood into the research of microwave vacuum electron. The two important echnologies which establish the foundation for VME devices are field emission and microfabrication technique. These devices can be worked at room temperature, have rapid toggle speed, and have great emission current density. In this paper, carbon nanotubes(CNTs) are used as the electron source in FE. And a new modulated electron beam electron gun is proposed. The main contents are as following:1. Starting with the principle of FE, the modulated electron beam equation is inferred. The equation shows that FE electron beam current can be modulated by changing the electric field, which is used to excited FE. Then the moulated signal is obtained. The model is established in the CST.2. Parallel-plate electron gun is modeled, and then the rate that electron beam go through the grid of anode plate is researched. The results show that when the side length of the grid is 5mm, and the side length of the grid: the gap between of two grids =5, the best through rate can be obtained. At last the parallel-plate electron gun is simulated in CST particle studio.3. The electron gun, which similar to rectangular waveguide- microstrip mode converter is established. In this electron gun, high frequency electric field can be input from the rectangular waveguide port, this high frequency electric field will contibute to the modulation of the FE electron beam current. The shape and the size of the electron beam channel are researched respectively. The results shows that when the shape is rhombus and the short diagonal of the rhombus is 6mm can be achieved better transmission effect.4. The FE electron beam current and the modulated depth of electron beam current of the CNTs are reseached when the three aspects(the strength of electrostatic field, the power of high frequency electric field and the frequency of high frequency electric field) are changed. The results are respectively: the higher the electrostatic field is, the larger the modulated amplitude is. Under the same input power, ?I increases with the electrostatic field’s growth. And the frequency has little or no effect on the current and modulated depth. At last the field emission cathode array is researched.