共查询到19条相似文献,搜索用时 93 毫秒
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基于几何光学理论和矢量绕射理论,研究了将回旋管及其他高功率微波器件的振荡输出模式转换成准光高斯波束的模式变换器,采用伏拉索夫(Vlasov)辐射器和三级准光反射面实现了准高斯模TEM00的横向输出.研究了Vlasov辐射器的工作机理,运用矢量绕射理论计算出波导辐射场,口面电流分布的方法计算反射面辐射场.通过编写程序设计了将94 GHz,模式为TE62的毫米波转化为准光高斯波束的内置式准光模式变换器.
关键词:
94 GHz回旋管
内置式准光模式变换器
Vlasov辐射器
矢量绕射理论 相似文献
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高功率微波运用的圆波导劈形端口辐射器(Vlasov-Nakajima辐射器)的辐射场可视为由平开口圆波导的辐射场和在该辐射场中的劈形圆波导段的散射场叠加而成。运用等效电磁流原理数值求解Kirchhoff-kottler积分获得圆波导TM01模的辐射场,再应用物理光学方法计算劈形段的散射场,并将计算的远场方向图与实验结果比较,获得较满意的一致。 相似文献
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《光子学报》2015,(10)
从Maxwell方程组出发,得到三层各向异性左手材料对称平面波导TM模的色散方程及功率流方程;利用多台阶近似法得到该类劈形平面波导TM0振荡模的反射系数和传输系数方程;根据TM模的色散方程、反射系数和传输系数方程画出相应的特性曲线.分析表明:随着电磁波的传输,TM振荡模传输系数ct2逐渐减小,但在零附近出现振荡,同时出现双模反射特性;随着波导长度的增加,第一类反射系数ar12从零开始逐渐增加,最终趋于恒定;第二类反射系数ar22单调增加,最大可接近于1.增加多层结构左手材料中金属填充比或电磁波频率,传输特性曲线下移,传输能力下降;第一类反射特性曲线下移,反射能力下降,但第二类反射特性曲线上移,反射加强. 相似文献
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具有刚性联接界面和滑移界面的层状固体媒质的声反射 总被引:4,自引:0,他引:4
利用矩阵方法,本文提出了声波从具有刚性联接和滑移界面的层状固体媒质反射特性的一般模型,导出了包含一个或两个滑移界面的层状固体媒质纵波和横波声反射系数解析表达式。文中还给出一些典型粘接件声反射系数的数值计算结果,为正确选择超声评价这些界面特性所采用的技术参数提供了依据。 相似文献
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A sort of tubular ultrasonic radiator used in ultrasonic liquid processing is studied. The frequency equation of the tubular radiator is derived, and its radiated sound field in cylindrical reactor is calculated using finite element method and recorded by means of aluminum foil erosion. The results indicate that sound field of tubular ultrasonic radiator in cylindrical reactor appears standing waves along both its radial direction and axial direction, and amplitudes of standing waves decrease gradually along its radial direction, and the numbers of standing waves along its axial direction are equal to the axial wave numbers of tubular radiator. The experimental results are in good agreement with calculated results. 相似文献
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I.IntroductionTheacousticbeams'f0cusingandscanninggeneratedbytransducerarraysonso1idsurfacep1ayaveryimportantroleinacousticimagingandultrasonoc1ectronicdevices.InourpreviouSworkt'-'],weinvestigatcdtheproperties0ftheacousticbeams'focusingandscanninga1ongthesymmetricalaxis,acousticfic1ddistributioninthewho1espaceandnearthefocus.Andwealsogaverigoroustheoretica1ana1ysis,numcrica1simu1ationandexperimenta1obscrvation.Butra-diationimpedanceandenergyofthesurfaceradiatorshavenotbeendiscussedyetbynow.… 相似文献
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A method of determining the field of a radiator from pressure measurements in its near zone is proposed. The method is based
on parametrization of the field by a set of complex spherical sources. The field of the radiator is calculated using the spherical
harmonic amplitudes, which are determined by solving the inverse problem. Results of numerical simulation are presented. 相似文献
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As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius. 相似文献
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John T. OBrien C.F. Hooper 《Journal of Quantitative Spectroscopy & Radiative Transfer》1974,14(6):479-496
The relaxation theory of plasma line broadening developed by Smith and Hooper, and extended by Smith, is applied to a charged radiator. The 304 Å Lyman alpha line of He II is chosen as an example. The radiator is assumed perturbed only by electronic and ionic electric microfields. The ions are treated in the static approximation. Two-component ion microfield distribution functions that allow for the presence of both He+ and He++ perturbers are employed. The fact that the radiator is charged complicates the treatment of electron perturbation; two different approaches are included. The first neglects the effect of the charge of the radiator on the perturbing electron and assumes that the perturbing electrons can be represented by momentum wave functions. This method corresponds to Smith's treatment of the electron perturbers in neutral hydrogen. The second includes the effect of the charge of the radiator on the perturbing electrons and represents the perturbing electrons by Coulomb wave functions; this calculation requires evaluation of free-free gaunt factors. The theory, with both the momentum and Coulomb perturber wave functions, predicts a blue asymmetry in the near wings of the line. These two approaches can be compared with the classical path approach of Griem and Shen. 相似文献
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In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL.Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy. 相似文献
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In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL. Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy. 相似文献