Research On Low-power Microwave Microplasma Source Based On Two-dimensional Reconfigurable Photonic Crystal

The low power microwave microplasma sources have advantages of simple structure,long life and stable state.Photonic crystals have properties of bandgap and defect state.Combined with low power microwave microplasma,the reconfigurable photonic crystals can be realized.Therefore,it is of great significance to study low-power microwave microplasma sources based on two-dimensional reconfigurable photonic crystals.Firstly,based on the theory of photonic crystals,the bandgap of two-dimensional photonic crystals arrayed periodically with alumina dielectric pillars is studied using COMSOL software in this thesis.The influence of parameters such as crystal lattices,cross-sectional shapes of dielectric column,column radius and lattice constants on the photonic crystal bandgap are analyzed.The transmission properties of two-dimensional photonic crystals are studied using HFSS software.Simulation results show that the bandgap of the photonic crystals with circular dielectric column is larger than that of the square dielectric column.When the frequency is 2.45GHz,the S₂₁ value of the square lattice photonic crystal array is smaller than that of the triangular lattice photonic crystal array.Secondly,according to the theory of photonic crystal line defects,the characteristics of bandgap,wave-guide and resonance of two-dimensional photonic crystal arrays fed with a coaxial-line in a specific space are studied.Simulation results show that the electromagnetic power transmittance of optimized two-dimensional photonic crystal array is less than 5.76%in the band of 2-3 GHz,and the minimum transmittance can reach 0.04%.The photonic crystal waveguide,whose dominant mode is TM mode,can be formed in the two-dimensional photonic crystal array.The S₁₁value of the photonic crystal equivalent waveguide with cylindrical dielectric pillars is-33.47d B at 2.45 GHz.The resonator structure is formed in the two-dimensional photonic crystal waveguide,and the single dielectric cylinder resonator has the best performance.When the resonant frequency is 2.45 GHz,the S₁₁ value is-33.75 d B,and its quality factor is 1070.Finally,the influence of properties(equivalent dielectric constant,loss tangent)on the resonance and transmission of the photonic crystal resonator after excitation of microwave microplasma at 2.45 GHz is studied.Research results show that the resonance and transmission of the photonic crystal resonator change with the equivalent medium characteristics of microwave microplasma.Therefore,the reconfigurability of photonic crystal is verified.The transmission power will decrease significantly with the microwave microplasma ignition.The work provides a reference for research of low power microwave microplasma sources based on tunable photonic crystal arrays.