排序方式: 共有17条查询结果,搜索用时 31 毫秒
1.
对于离散的金属柱结构构建的周期性平板慢波系统,本文利用3维FDTD方法结合HFSS仿真软件深入分析了该慢波系统的高频特性.研究了金属柱高度、周期长度对色散特性的影响,计算了耦合阻抗,并与传统光栅慢波系统特性进行了对比分析.分析表明金属柱慢波系统既有与传统光栅慢波系统相似的高频特性,又具有独自的特点,位于离散的金属柱周期间隙中的电子注互作用耦合阻抗具有对称性;金属柱结构用作真空电子器件的高频系统可增加发生有效互作用的电子注厚度,降低起振电流密度,提高器件效率.本文的分析结果为设计低电流密度工作的多电子注短毫
关键词:
金属柱平板慢波系统
3维FDTD算法
色散特性
耦合阻抗 相似文献
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3.
本文提出一种半径和周期双重扰动的非均匀圆波导TE0n模式变换器. 通过耦合波理论(CWT)和数值优化方法对该模式变换器进行研究, 计算结果与电磁仿真软件基本一致. 与传统的均匀结构半径微扰模式变换器比较, 非均匀扰动结构TE0n模式变换器可以在更少的波纹周期内实现高于均匀结构的模式转换效率, 95%功率转换绝对带宽增加150%, 器件长度减小接近一半. 本文的研究工作为设计轴向尺寸短、工作带宽大、 转换效率高的高功率回旋管外接模式变换器提供了重要参考. 相似文献
4.
Dispersion characteristics of two-dimensional unmagnetized dielectric plasma photonic crystal 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper studies dispersion characteristics of the
transverse magnetic (TM) mode for two-dimensional unmagnetized
dielectric plasma photonic crystal by a modified plane wave method.
First, the cutoff behaviour is made clear by using the
Maxwell--Garnett effective medium theory, and the influences of
dielectric filling factor and dielectric constant on effective
plasma frequency are analysed. Moreover, the occurence of large gaps in
dielectric plasma photonic crystal is demonstrated by comparing the
skin depth with the lattice constant, and the influence of plasma
frequency on the first three gaps is also studied. Finally, by using
the particle-in-cell simulation method, a transmission curve in the
\Gamma -X direction is obtained in dielectric plasma photonic
crystal, which is in accordance with the dispersion curves
calculated by the modified plane wave method, and the large gap between
the transmission points of 27~GHz and 47~GHz is explained by
comparing the electric field patterns in particle-in-cell
simulation. 相似文献
5.
We study a two-stream backward-wave oscillator with a slot-hole structure at short millimeter waves with the help of a three-dimensional particle-in-cell simulation. In order to increase the interaction region of the electron beam, the efficiency and the output power, a slot-hole loaded rectangular waveguide structure used as the high-frequency system is proposed. Based on the mechanism of the backward-wave oscillator, a slow-wave oscillator with a frequency of 0.14 THz is designed. The simulations show that the output power and the efficiency of the oscillator can be enhanced due to the coupling between the two beams through the slot holes. The interaction efficiency is 5.18%, and the starting current density is below 5 A·cm-2 for the two beams. These attractive results indicate that, based on the two-stream backward-wave oscillator, we can get short millimeter wave sources with high power and low current density. 相似文献
6.
提出了一种变态光子带隙结构,研究了由这种结构构成的周期慢波系统的Cherenkov辐射源的特性. 利用高频仿真软件以及三维粒子模拟软件对变态及常态光子带隙慢波系统中类TM01模的色散特性及注-波互作用物理过程进行了模拟研究. 结果表明,在变态光子带隙慢波系统中,类TM01模纵向场分量沿角向分布均匀性得到明显改善,能有效抑制非对称模式,提高输出频谱纯度及注-波互作用效率.
关键词:
Cherenkov辐射源
变态光子带隙结构
慢波系统
三维粒子模拟 相似文献
7.
分别以2,4,5-三氯苯胺和盐酸氨基脲、甲酸为起始原料, 设计并合成两个系列新型1,2,4-三唑啉酮类化合物(5, 7). 通过 1H NMR, MS和元素分析确证了其结构, 生物活性测定结果表明, 化合物5系列的除草效果优良, 而化合物7系列则基本没有除草活性, 但表现出很强的促进黄瓜子叶生根活性. 相似文献
8.
Three-dimensional simulation of Ka-band relativistic Cherenkov source with metal photonic-band-gap structures 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In the simulation, a perfect match layer boundary is employed to absorb passing band modes supported by the PBG lattice with an artificial metal boundary. The simulated axial field distributions in the cross section and surface of the SWS demonstrate that the device operates in the vicinity of the π point of a TM01-like mode. The Fourier transformation spectra of the axial fields as functions of time and space show that only a single frequency appears at 36.27 GHz, which is in good agreement with that of the intersection of the dispersion curve with the slow space charge wave generated on the beam. The simulation results demonstrate that the SWS has good mode selectivity. 相似文献
9.
为进一步寻找高效、安全和对环境更加友好的除草剂, 以商品化除草剂单嘧磺酯为研究基础, 对其结构中的苯环5-位取代基作了结构修饰, 合成了26个未见文献报道的新型N-(4'-取代嘧啶-2'-基)-2-甲氧羰基-5-苯甲酰胺基苯磺酰脲化合物, 通过1H NMR、质谱及元素分析确定了化合物的结构. 经油菜平皿法及盆栽法测试了所有化合物的除草活性, 结果表明, 当苯环5-位取代基为苯甲酰胺时, 活性较好, 其对双子叶植物的除草活性与商品化的甲嘧磺隆相当. 相似文献
10.
本文提出在Kα波段圆柱过模结构绕射辐射器件(RDG)中引入一种带有锥度结构的同轴内开槽布拉格反射器.采用复功率守恒技术(CCPT)对该反射器的频率响应特性进行分析.研究了相位匹配段长度,波纹槽深及锥度对反射器频率响应特性的影响,分析了波纹初始相位对反射器选模特性的影响,发现该反射器具有良好的模式选择特性.本文的研究工作为同轴Bragg反射器结构的研究提供了重要的理论分析手段.
关键词:
同轴Bragg反射器
频率响应特性
复功率守恒
绕射辐射振荡器 相似文献