基于矩形结构的大功率微波弯头研究

发布时间：2019-04-13 09:07

【摘要】：高功率回旋管因其具有高功率和宽带宽的优势,在毫米波雷达和通讯等领域有着广泛的应用前景,得到国内外研究人员的重视。随着应用系统的不断发展,与回旋行波管配套的高功率传输器件,也成为了国内外众多科研人员积极研究的热点。波导弯头是微波传输系统中的重要器件之一。在高功率传输的情况下,圆波导弯头中工作模式与寄生模式之间极易出现相互耦合的现象,而且这种耦合很难通过变曲率的方式去消除,势必会极大的影响弯头工作性能。与圆波导相比,在过模情况下,弯曲矩形波导中的模式之间的耦合更加容易控制,能否利用矩形波导的这一特性实现波导转弯的宽频带和高效率是本论文关注的重点技术问题。本论文的主要工作和贡献如下:1、研究了过模弯曲矩形波导中的模式耦合问题,建立了相应的数学模型,并对矩形波导中各模式之间的耦合系数进行了详细的推导和归纳总结。2、在理论推导的基础之上,编写了弯曲矩形波导耦合波方程组的数值求解程序。并在仿真软件HFSS中建立了仿真模型,将仿真计算结果与数值计算结果进行了对比,验证了数值计算程序的正确性,但在分析速度方面,数值计算程序的速度约为仿真软件计算速度200倍,这样大大缩短了分析所需的时间,为后续电大尺寸弯头的优化计算提供了必要的工具。3、利用数值计算工具和仿真软件,优化设计了具有矩形结构,口径为50mm,工作在Ku波段的TE01弯头。计算结果如下:传输效率在96%以上的带宽可达到13.9%,最高传输效率为99.97%。4、利用数值计算工具和仿真软件,对一种极化可控的TE11弯头进行了分析和优化设计,该弯头工作于Ku波段,口径为32mm。提出的结构可以保证在引导TE11模式高效率转弯的同时,既能够实现TE11模式线、圆极化之间相互转变也可以实现TE11模式极化不变的传输。为了验证方案的可行性,对第二种情况的弯头进行了加工测试,S-参数的测试结果表明:在13GHz-15GHz的频率范围内,TE11弯头的传输效率高于97%;空间辐射场测试表明:线极化TE11模式在经过该弯头之后能够保持极化方向不变的输出,功率容量测试结果表明:在频率13GHz~15GHz、峰值功率120k W、平均功率10.4k W的情况下,研制的弯头未发生击穿现象。5、鉴于矩形弯曲波导在弯头中的成功应用,本章节还尝试将矩形弯曲波导应用到了TE01-TE11蛇形弯曲模式变换器中的设计中,期望能够探索出一种宽频带的模式变换器设计方案。结合数值计算工具和仿真软件,对一种工作在Ka波段,口径为23mm,改进型的TE01-TE11蛇形弯曲模式变换器进行了优化设计。计算结果表明:最高转化效率为98.5%,相对带宽为11.5%。
[Abstract]:Because of its advantages of high power and wide bandwidth, high power gyrotron has a wide range of application prospects in millimeter wave radar and communication, and has been paid more attention by researchers at home and abroad. With the development of the application system, the high power transmission devices with cyclotron traveling wave tube (TWT) have become the active research hotspot of many researchers both at home and abroad. Waveguide elbow is one of the most important devices in microwave transmission system. In the case of high power transmission, the coupling between operating mode and parasitic mode is easy to occur in circular waveguide elbows, and this coupling is difficult to be eliminated by varying curvature, which will greatly affect the performance of the elbow. Compared with circular waveguides, the coupling between modes in curved rectangular waveguides is easier to control in the case of over-mode. Whether we can make use of the characteristics of rectangular waveguides to realize the wide-band and high efficiency of waveguide turning is the focus of this paper. The main work and contributions of this thesis are as follows: 1. The mode coupling problem in over-mode bending rectangular waveguide is studied and the corresponding mathematical model is established. The coupling coefficients among the modes in rectangular waveguides are deduced and summarized in detail. 2. On the basis of theoretical derivation, a numerical program for solving the coupled wave equations of curved rectangular waveguides is compiled. The simulation model is established in the simulation software HFSS. The simulation results are compared with the numerical results, and the correctness of the numerical calculation program is verified, but in the aspect of the analysis speed, the simulation results are compared with the numerical results. The speed of the numerical calculation program is about 200 times that of the simulation software, which greatly shortens the time required for analysis and provides the necessary tools for the optimization calculation of the subsequent electrically large size elbows. 3, using the numerical calculation tool and simulation software, The TE01 elbow with rectangular structure, 50mm aperture and working in Ku band is optimized. The results are as follows: the bandwidth of transmission efficiency above 96% can reach 13.9%, and the highest transmission efficiency is 99.97%. Using numerical calculation tools and simulation software, an TE11 elbow with controllable polarization is analyzed and optimized. The elbow operates in the Ku band and has a diameter of 32mm. The proposed structure can not only guide the high efficiency turn of TE11 mode, but also realize the transmission of TE11 mode line, circular polarization and constant polarization of TE11 mode. In order to verify the feasibility of the scheme, the processing test of the elbow in the second case was carried out. The test results of S-parameter show that the transmission efficiency of the 13GHz-15GHz elbow is higher than 97% in the frequency range of TE11; The space radiation field test shows that the linear polarized TE11 mode can keep the output of the polarization direction unchanged after passing through the elbow. The power capacity test results show that: when the frequency is 13GHz / 15GHz, the peak power is 120kW and the average power is 10.4kW. 5. In view of the successful application of rectangular bend waveguide in the elbow, this chapter also tries to apply the rectangular bend waveguide to the design of TE01-TE11 serpentine bending mode converter. It is expected that a design scheme of broadband mode converter can be explored. Combined with numerical calculation tools and simulation software, an improved TE01-TE11 serpentine bending mode converter operating in Ka band with an aperture of 23 mm is optimized. The results show that the highest conversion efficiency is 98.5% and the relative bandwidth is 11.5%.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN12

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