| It is one of an indispensable electrical device for microwave vacuum devices in fields of microwave or millimeter wave, especially in microwave communication. There are some merits like high power, high gain, high efficiency and broad bandwidth for the microwave tube. At the present time, microwave tube has been found application in fields of civilian and military, which include of wide bandwidth communication, radar, electronic jamming and electronic countermeasure. Since high frequency characteristics of slow-wave system may have a crucial influence to some parameters of microwave tube, which are work bandwidth, gain, output power and efficiency, people usually take some adjustment on its structure or material to improve the performance based on correlative theory. It is gone into simple and economy duo to the import of numerical computation.For the purpose of accurate and fast emulation and simulation to the slow-wave structure (SWS), in-depth researches have been developed on the numerical method of high frequency characteristics of SWS in this paper. Based this work and research findings of References[1], we have consummated the High Frequency Circuit Simulator, which is the first domestic software to simulate three dimensional SWS and named HFCS in short words. HFCS, which is using Finite Element Method and Maxwell's electromagnetic theory as the foundations of mathematical and physic, is able to simulate SWS with any structure and material in three dimensional. Currently, as a component of Microwave Tube Simulator Suite, this soft has been widespread used in some research entities, and gained good evaluation. There are some main work and innovations:1. Theory of Finite element method has been deeply studied, and application of vector FEM basis functions in electromagnetic has been grasped. The vector basis functions are twice differentiable, so there will be no pseudo solutions and problems of field singularity when deal with vector questions.2. At first, we proceeded from the boundary value problem and combined with the theory of electromagnetic of SWS to analyze and deduce its functional. Next, we used the variation method of Ritz and vector basis functions to disperse the functional. Finally, we got the matrix equation which can be solved in numerical.3. Approach of imposing the period boundary conditions has been improved and the generalized variation theory has been used, according to that the calculations of dielectric loss in SWS was realized.4. We studied the technology of Auto Mesh Refinement (AMR). What the technical problem on it is the determination of error and the local control of mesh. Simply, we exploit the Eigen value as the judge reference and preliminarily implement the AMR in this paper.5. A simulator of SWS which is using C++ underlying Windows is presented. With model that has been produced by MTDE this soft can compute and give the parameter of SWS, such as Phase velocity, Coupling impedance and Attenuation constant.6. Lots of example model have been calculated to verify the precision of HFCS with analytical solution, experimental value and solution of HFSS. Also, products which were using have been calculated by HFCS and compared the results with the test value. The purpose of what we have done is to check the HFCS in engineering. |
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