Millimeter Wave Quasi-optical Power Synthesis Technology Research And Prototype

In this dissertation, a systematic study is carried out on a class of quasi-optical power combining schemes which are able to operate in short MM-wave and up to Thz frequency band, and they are all designed by applying scalar diffraction theory. The simulation and optimization methods for system design are investigated thoroughly. Based on the full understanding of the advantages and disadvantages of all previous systems, a sheme with new structure and some new design stratigies are proposed. A quasi-optical power combining system prototype is now nearly finished, and two pieces of software which are Hybrid Parallel Optimization System and Quasi-optical Power Combiner Design Software have been designed which integrate all the thoerical improvements made in this dissertation.The main contributions and innovations of this thesis are listed below:1. To sovle the most difficult problem which is optimization, a comparative study has been made on different types of optimization algorithms for electromagnetics which are gradient method, direct method and space mapping. Hybrid Parallel Optimization System, which can accelerate EM optimization through multi-PCs and multi-threads, is designed based on this study.2. Summarized the theriotical foundations of Talbot grating, fourier grating and shaped reflector quasi-optical power combining systems. The characteristics of different schemes and the scope of application of different algorithms are disscused. A method for designing a near field Fourier grating is proposed. Finally, Quasi-optical Power Combiner Design Software has been designed based on previous study;3. A optimization strategy which applies surface interpolation with sensitivity analysis is raised. By using this method, the number of optimization variables can be cut down largely, as a result, the optimization process will be much easier. Besides, the smoothness of the optimized surface can be guaranteed by surface interpolation. As a result, the optimized structure is smooth enough to be fabricated without revising and the smoothing procedure can be eliminated from the design process.4. A more compact near field single reflector system is proposed, by using near field grating projection method, the optimization problem of single reflector power splitter/combiner has been solved.5. A dual reflector splitter, a single reflector splitter and a spaceborne reflector antenna are designed successfully. By comparing the simulation result of PO, FDTD and scalar diffraction mehod, we verified that the simulation algorithm in this thesis has sufficient accuracy, meanwhile, is much faster than the other two.