排序方式: 共有28条查询结果,搜索用时 78 毫秒
1.
由于目前常用的磁聚焦系统设计方法不能直接计算带有非轴对称开口磁环的磁系统,因此在行波管磁系统实验测试基础上,提出了双面带极靴的开口磁环体积等效概念:将开口磁环等效为相等体积磁性材料的2维轴对称磁环,两者都双面带极靴时轴上的磁场值相等。使用2维电磁计算软件FEMM计算了采用该等效模型后的周期磁聚焦系统的轴上磁场值,计算结果与带有开口磁环的实际系统测试值符合良好,两者相差仅3×10-3 T。该2维等效模型能代替开口磁环进行计算。 相似文献
2.
An open-styled dielectric-lined azimuthally periodic circular waveguide for a millimeter wave traveling-wave tube 下载免费PDF全文
An open-styled dielectric-lined azimuthally periodic circular waveguide (ODLAP-CW) for a millimeter-wave traveling-wave tube (TWT) is proposed, which is a modified form of a dielectric-lined azimuthally periodic circular waveguide (DLAP-CW). The slow-wave characteristics of the open-styled DLAP-CW are studied by using the spatial harmonics method, which includes normalized phase velocity and interaction impedance. The complicated dispersion equations are numerically solved with MATLAB and the results are in good agreement with the simulation results obtained from HFSS. The influence of structural parameters on the RF properties is investigated based on our theory. The numerical results show that the optimal thickness of the metal rod can increase the interaction impedance, with the dielectric constant held fixed. Finally, the slow-wave characteristics and transmission properties of an open-styled structure are compared with those of the DLAP-CW. The results validate that the mode competition is eliminated in the improved structure with only a slight influence on the dispersion characteristics, which may significantly improve the stability of an open-styled DLAP-CW-based TWT, and the interaction efficiency is also improved. 相似文献
3.
This paper presents a theory on accurately analysing the dispersion relation and the
interaction impedance of electromagnetic waves propagating through a helical groove
waveguide with arbitrary groove shape, in which the complex groove profile is
synthesized by a series of rectangular steps. By introducing the influence of
high-order evanescent modes on the connection of any two neighbouring steps by an
equivalent susceptance under a modified admittance matching condition, the
assumption of the neglecting discontinuity capacitance in previously published
analysis is avoided, and the accurate dispersion equation is obtained by means of a
combination of field-matching method and admittance-matching technique. The validity
of this theory is proved by comparison between the measurements and the numerical
calculations for two kinds of helical groove waveguides with different groove
shapes. 相似文献
4.
从麦克斯韦方程出发,分析了带状电子注在螺线管磁场中传输时Diocotron模形成的原因;对周期凸起磁场(PCM)聚焦下的电子受力进行分析,分析表明PCM磁场能够抑制Diocotron模。结合理论分析,利用3维粒子模拟程序, 对Diocotron模的形成进行了研究,并利用了PCM磁场聚焦带状电子注,抑制Diocotron模。通过粒子模拟研究了磁场大小对PCM磁场抑制Diocotron模的影响,结果表明:磁场减少导致空间电荷力和磁力需要平衡,其侧面包络变厚。 相似文献
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对曲折圆形槽波导新型慢波系统的高频特性进行了研究,通过理论分析和数值计算,得到了它的色散曲线和耦合阻抗表达式,并分析了结构参数变化对色散特性和耦合阻抗的影响。研究表明:当周期变小时色散减弱,耦合阻抗增加;而增大直波导长度时色散变弱,但同时耦合阻抗也会下降。因此较小的周期有利于改善曲折圆形槽波导慢波电路的高频特性。鉴于这种电路的耦合阻抗较低,可以适当地减小直波导长度来提高耦合阻抗。曲折槽波导结合了曲折波导散热能力强、色散特性好、容易加工和槽波导单模工作、低损耗、大尺寸等优点,在毫米波及亚毫米波段的行波管中具有较好的发展前景。 相似文献
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在对周期性结构进行谐波分析的基础上,导出了非截面二维光子晶体排列矩形波导的本征值方程. 基于此方程,可以对该类光子晶体波导的所有可能模式进行分析. 分析认为,非截面二维光子晶体排列矩形波导内能存在的模式包括E(y),TEy,H(y)和TMy模式;改变波导高度,可以实现E(y)模式和H(y)模式与其他模式通带的完全分离. 然而改变任一结构参数,都不能使E(y)和H(y)的各个模式通带,以及E(y)1模式和H(y)1模式的通带完全隔离. 波导单模工作的带宽由E(y)1和E(y)2模式的低端截止频率决定.
关键词:
波导
光子晶体
本征值方程
模式 相似文献
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用阶梯近似的方法分析任意槽形加载的圆波导慢波系统,利用各阶梯相邻面的导纳匹配条件 以及中心互作用区与加载区的场匹配条件,获得了任意槽形加载周期慢波结构的统一色散方 程. 利用该色散方程,得到色散特性与CST MWS仿真软件模拟结果良好符合. 分别求解几种 特殊槽形加载慢波结构的色散特性及耦合阻抗,其中,三角形结构色散和耦合阻抗均最弱, 而倒梯形结构色散最强,耦合阻抗最大.
关键词:
任意槽形
慢波结构
色散特性
行波管 相似文献