This article presents the electromagnetic and particle-in-cell (PIC) simulation results of an X-band coaxial magnetron obtained using commercially available 3-D simulation tools CST particle studio. The operating frequency of the magnetron is 9.5 GHz with the tuning range of 8.5–9.5 GHz and the output power of 200 kW. It is observed by simulation that stable operation is not possible without eliminating the spurious cavity modes. For this purpose, the inner wall of the anode block has been loaded with the lossy dielectric material in the form of an annular cylinder having dielectric permittivity 23 and loss tangent 0.24. When the anode wall is loaded with lossy dielectric material, eight space charge spokes are observed during the stable operation of the magnetron which correspond to $\pi $ -mode of operation in a coaxial magnetron having 16 vanes. A clear oscillation spectrum with a single peak is observed at 9.350 GHz with no other noticeable peaks. The radiated output power obtained in simulations is about 235 kW, with an anode voltage of 23 kV and an anode current of 30 A. The applied external magnetic field is 0.36 T and the corresponding efficiency of the magnetron operation is ~34%. The frequency tunability of the magnetron and the effect of frequency variation on the output power of the magnetron have also been studied by varying the length of the outer coaxial cavity. The frequency has been varied from 8.65 to 9.577 GHz and the corresponding variation in the output power is about 16%.

中文翻译：

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在X波段可调谐同轴脉冲磁控管中使用有损介电材料抑制寄生腔模

本文介绍了使用商用3-D仿真工具CST Particle Studio获得的X波段同轴磁控管的电磁和单元内粒子（PIC）仿真结果。磁控管的工作频率为9.5 GHz，调谐范围为8.5–9.5 GHz，输出功率为200 kW。通过仿真观察到，不消除寄生腔模就不可能稳定工作。为此目的，阳极块的内壁已装载有呈圆柱体形式的有损耗介电材料，该圆柱体的介电常数为23，损耗角正切值为0.24。当阳极壁上加载有损耗的介电材料时，在磁控管稳定运行期间会观察到八个空间电荷辐条，分别对应于 $ \ pi $ -在具有16个叶片的同轴磁控管中的工作模式。在9.350 GHz处观察到具有单个峰值的清晰振荡频谱，没有其他明显的峰值。在仿真中获得的辐射输出功率约为235 kW，阳极电压为23 kV，阳极电流为30A。施加的外部磁场为0.36 T，相应的磁控管工作效率为〜34％。通过改变外部同轴腔的长度，还研究了磁控管的频率可调性和频率变化对磁控管输出功率的影响。频率从8.65到9.577 GHz不等，输出功率的相应变化约为16％。