Study On The Cherenkov Radiation Sources With Plasma-filled Metal Photonic Crystal

Photonic crystal is a periodic structure with properties of crystal which consisting of two or more than two kinds of materials. Since the conception of photonic crystal is proposed, the theoretical analysis method has been gradually improved and a variety of photonic crystal devices have been used. However, the research on theory and application of special type photonic crystal is still the focus of current research. Therefore, this dissertation studies the band gap characteristics of metal photonic crystal and constructs related microwave devices. The results of this research work provide theoretical and experimental foundation for the development of plasma filled metallic photonic crystal(PMPC).The main work and innovations are as follows:The band gap characteristics of plasma filled two-dimensional square lattice and triangular lattice metallic photonic crystal are analyzed by finite difference time domain method(FDTD). We make a comparative analysis of the affection of plasma density on the global band gap characteristics and local band gap of the TM and TE polarized wave of the two kinds of structure. Due to the introduction of the background plasma, dispersion curves of two dimensional(2D) PMPC shift clearly to the higher frequency direction and a new band below the plasma cutoff frequency emerges in TE polarization band diagram. In addition, the plasma density can control the width and position of TE and TM polarized wave band gap.Based on the above research, we analyze the band gap properties of magnetized PMPC. The results show that new forbidden bands and flat bands emerge in the TE diagram of Magnetized PMPC except the cut-off frequency. The flat bands, band gaps and the local positions and widths of the gaps can be adjusted by the magnitude of the external magnetic field. The research results provide a theoretical basis for the design of tunable photonic crystal devices.The characteristics of a slab PMPC waveguide filter with line defect are analyzed. The results show that metal column number, fill ratio and plasma density have a great influence on the propagation characteristics of the non magnetized system. The amplitude of defect modes decreases with the increase of metal columns layer, while the frequency has little variation. The filling rate and plasma density can adjust the frequency of defect mode in a large range. A new pass band appears in the frequency domain of observing line for magnetized PMPC system. Simultaneously, a new band gap emerges between the new pass band and the original one. The band gap decreases and the defect mode frequency increases with the variation of magnetic field intensity. In high magnetic field, a new defect mode appears, and the two defect modes exist in certain magnetic field intensity range.Based on the band diagram and defect mode properties of PMPC, the field distribution characteristics and mode frequency of an open resonator composed of PMPC are demonstrated. The results show that the TM01 mode in the cavity can be easily limited. The modes frequencies increase with the increase of the normalized frequency.A PMPC disk loaded open resonant cavity slow wave structure(SWS) is constructed. The dispersion characteristics of PMPC SWS are simulated by CST software with a spoke antenna as the input and output devices. Dispersion characteristics of structural parameters of the PMPC SWS are analyzed based on excitation technique. The results show that the plasma density, metal disc inner radius, the cycle length and other parameters can change the dispersion characteristics of slow wave structure. At the same time, the excitation validity of spokes antenna is shown.The physical process of beam wave interaction in the PMPC SWS is simulated by the software of Chipic. The results show that the SWS have a good mode selection characteristic. Background plasma can enhance the SWS surface field and improve the angular distribution of the field. The output power and efficiency of the Cherenkov device can be improved obviously with plasma filled.The hot test of metal photonic crystal SWS based on Cherenkov radiation is accomplished. We assemble the experimental system, finish the device tests, introduce the experiment principle and process, and design the experimental system of plasma filled. The experimental results show that the operating mode and the Cherenkov radiation source frequency are in agreement with the theory and simulation results. The measured radiation power and efficiency are slightly lower than the results of simulation.