全腔输出相对论磁控管输出模式转换结构的理论设计和数值模拟  

Design and simulation of output mode conversion structure of relativistic magnetron with all cavity output

作　　者：杨温渊[1] 董烨[1] 董志伟[1] Yang Wen-Yuan;Dong Ye;Dong Zhi-Wei(Institute of Applied Physics and Computational Mathematics,Beijing 100094,China)

机构地区：[1]北京应用物理与计算数学研究所,北京100094

出　　处：《物理学报》2018年第18期318-325,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11305015;11475155;11875094);中国工程物理研究院科学技术发展基金(批准号:2015B0402091)资助的课题~~

摘　　要：采用全腔输出结构后,相对论磁控管径向尺寸显著减小,轴向长度也有较大幅度的缩短.但是,由于输出结构为三个相对独立的扇形波导,实际应用时,一般需要对微波输出模式进行转换.针对全腔输出相对论磁控管,本文研究了两种输出模式转换结构并利用三维全电磁粒子模拟程序对其进行了研究.首先研究了将三个扇形波导角向增宽从而渐变或者突变为一个同轴波导的情况,研究结果表明,两种情况下输出微波功率均大于采用传统三个独立扇形波导输出时的90%,输出模式主要是TEM模.其次研究了输出区由三个扇形输出波导分别变换为三个截面大小与之接近的矩形输出波导的可行性,研究结果表明,注入扇形波导中的TE_(11)模式几乎全部转换为矩形波导中的TE_(10)模式.实际应用时,可根据需要选择上述输出模式转换结构.A relativistic magnetron using all cavity extraction and semi-transparent cathode has the virtues of compactness,high output power and high efficiency. The three-dimensional particle-in-cell simulations show that 1.15GW output microwave with an efficiency about 50% can be obtained at S-band with pure TE（11） mode of the fan waveguide.However, due to the fact that the output structure is composed of three detached fan waveguides, mode conversion structure in the output region is required for the convenience of practical applications. Therefore, two mode conversion structures are studied for the output mode conversion. The first structure is to widen gradually or abruptly the fan waveguide in the azimuthal direction from a given position（starting point） along the microwave transport direction. And then the three fan waveguides are connected into one coaxial waveguide. The effects of the position of the starting point on the beam-wave interaction and microwave extraction are numerically studied. For the convenience of description, we define L as the axial distance between the center of the output coupling hole and starting point. Simulation results show that for the abrupt and gradual variation case, when the length of L changes in a relatively wide region, the output power is larger than 1.0 GW in TEM mode at S-band. It is about 90% of the conventional fan waveguide with 1.15 GW.For the gradual variation case, the optimal value of L equals 10.0 cm, and the corresponding output power is beyond 1.0 GW. For the abrupt variation case, the optimal value of L equals 13.75 cm, the corresponding output power is about 1.15 GW. But in the abrupt variation case, the output power is a little more sensitive to the value of L. The second structure is to convert the fan waveguide into a rectangular waveguide. A compound waveguide composed of a section of fan waveguide and a section of rectangular waveguide is designed for studying its feasibility. In the compound waveguide,the wide edges of the cross section of the rectang

关 键 词：相对论磁控管 半透明阴极 全腔耦合输出 扇形波导 

分 类 号：TN123[电子电信—物理电子学]