Research On High-frequency System Of Dual-grating Diffraction Radiation THz Source

The broad application prospect of Terahertz-waves in areas such as broadband communication, radar, electronic warfare, astronomy, Medical imaging, nondestructive testing and security check which makes the terahertz technology has become one of the hottest research directions in twenty-first century. Lack of miniature and high-power terahertz source is the bottleneck of development of terahertz technology. As a newly developed vacuum terahertz source, dual-grating diffraction radiation device has the advantages of compact dimensions, high efficiency and low voltage. In the dissertation, the high frequency system of dual-grating diffraction radiation device was studied, and our researches are mainly focus on the following aspects:l.The high frequency structure was studied, and the modes and distribution of field were analyzed. The working mode of dual-grating diffraction radiation device were analyzed by studing the mode characteristics of high frequency system. And the high frequency characteristics was studied by electromagnetic field method in this dissertation.2.The intensity of electromagnetic field and Q characteristics of dual-grating diffraction radiation device was studied. The influence of structure parameters on the mode distribution and resonance frequency were analyzed, and the influence of structure parameters on the Q characteristics was also studied. A newly simulation method of analyzing resonant frequency and field distribution was presented in the dissertation.3.The characteristics of mode competition in dual-grating diffraction radiation device was studied, and the effective methods to ensure stable operation on working mode was presented.4.The beam-wave interaction of dual-grating diffraction radiation device was studied. Meanwhile, the the process of bunching particles, the output characteristics and electric tuning characteristics were also simulated by particle-in-cell method.5.The processing method of high depth width ratio of grating structure in dual-grating diffraction radiation device was explored, which providing an effective reference for the processing of this structure.6.A new diffraction radiation device based on gratings structure was presented. The numerical analysis of mode competition and field distribution were carried out which was intended to lay the groundwork for future research.As a new type of THz vacuum device, the technique of dual-grating diffraction radiation device is immature. The high frequency system of dual-grating diffraction radiation device was studied in details in the dissertation, and the results show that the dual-grating diffraction radiation device is a novel promising vacuum tube with compact dimensions and high power. The studies in the dissertation can provide some guidance to the design and optimize of dual-grating diffraction radiation device.