Research On Low Loss Beam Adjust Technology Based On Holography

With the development of science and technology,the technology of high-power millimeter wave has gained increasing attention in the fields of scientific research and military.In the research of high-power millimeter wave,how to achieve beam adjustment with low loss and high efficiency is one of the problems must be solved.In addition,how to reduce the diffusion of millimeter wave during propagation,to improve the effective distance is the key point to expand the application of high-power millimeter wave.Based on the holographic theory,this thesis focusses on the research of uniform intensity field generation,single frequency and dual frequency high purity Bessel beam generation and optimization algorithms for the application such as high efficiency electromagnetic wave radiation and vortex wave radar.The work of the thesis is as follows:1.A high-power millimeter wave uniform algorithm based on mirror is proposed.The classic GS algorithm has been improved by some methods such as changing initialized phase selection,adding weight factor,which improves the scalar coupling and uniformity of output field.Based on the proposed improved GS algorithm,a numerical optimization program was developed,and a uniform intensity field generation system was designed and validated by simulation software.The results show that the designed system can achieve a scalar coupling value up to 97.8%,while amplitude non-uniformity is only4.6%.2.The research on single frequency high-power millimeter wave vortex beam forming with mirror has been carried out.Two kinds of dual mirror beam forming algorithm was investigated.Aiming at the shortcomings of the algorithms,a step-by-step beam forming algorithm was proposed,which improves the purity,bandwidth,and calculation speed of output beam.The proposed algorithm can achieve arbitrary vortex beam forming.Based on the algorithm,a mode-4 Bessel beam generation system was designed and validated by simulation and experiment.Results show that the OAM mode purity of the output beam can reach over 93% in the range of 31 to 35 GHz.3.The research on dual frequency high-power millimeter wave vortex beam forming with mirror has been carried out,achieving the generation of different vortex beam.Dual frequency beam forming algorithm was proposed,and a dual frequency beam generation system was designed.Simulation and experiment have been taken,and the results show that the OAM mode purity can reach 94.1% and 93.4% at low and high frequencies,respectively.