高功率回旋行波管新型宽带输出窗的设计

首先利用场匹配理论和传输级联矩阵建立多层介质窗的普遍分析方法,对回旋行波管输出窗进行解析分析,在理论分析和数值计算的基础上得到回旋行波管宽带输出窗的结构和尺寸;然后利用三维高频分析软件HFSS进行仿真和验证.通过热分析和优化设计,在Ka波段获得了平均功率容量达到50 kW,反射系数小于-20 dB的带宽约为3.6 GHz的高性能新型宽带输出窗.冷测实验表明,冷测结果与数值计算结果较为吻合.     

太赫兹回旋管蓝宝石输能窗的设计及实验

针对170 GHz兆瓦级回旋管短脉冲实验对蓝宝石输能窗的实际要求,分析了蓝宝石窗传输高斯波束的反射和吸收特性,优化设计了低反射、低损耗蓝宝石输能窗的工程方案。对研制的蓝宝石窗部件进行微波冷测,驻波比(VSWR)小于1.1,验证了蓝宝石窗的低反射特性;计算结果表明该结构的最大输出平均功率阈值为590 W。对使用该蓝宝石窗研制的170 GHz回旋管进行测试,验证了理论计算的功率阈值,为大功率回旋管蓝宝石输能窗的实际应用提供了依据。     

3mm回旋行波管高频窗的设计

利用等效电路理论和网络传输矩阵理论设计出了可承受平均功率10kW以上的3mm回旋行波管的输入输出窗。并用三维高频结构仿真软件HFSS和CST-MW S模拟结果与数值计算结果进行了比较,三者吻合得很好。在W波段驻波系数小于1.2的情况下,得到盒型窗输出带宽12.4GHz(13.2%);三层介质矩形窗输出带宽为18.8GHz(20%)。本文所推导的理论结果可直接运用于更高频段高频窗的设计中。     

一种Ka波段回旋行波管输出窗设计

针对Ka波段回旋行波管输出窗介质窗片易打坏的问题,引入了3层介质厚窗结构和液冷结构。利用微波网络场匹配理论建立传输级联矩阵的方法对多层窗片结构输出窗进行研究,给出Ka波段回旋行波管一种新型中间液冷结构输出窗的参数,通过CST进行仿真验证和优化处理,并进一步结合热损耗公式和ANSYS Workbench对输出窗进行热分析,在26.3~35.7 GHz频带范围内,实现S_(21)>-0.5 d B。     

采用混合模式传输的新型超宽带盒型窗

在传统的场匹配理论的基础上建立起盒型窗的通用传输参数矩阵,并提出了一种新型的混合模式传输方法来扩展盒型窗带宽.在研究结果的基础上,通过理论分析和数值计算得到了能满足Q波段超宽带带状束行波管所需求的新型混合模式传输盒型窗的初始结构和尺寸、利用三维高频分析软件HFSS优化并得到了最终结构参数.通过仿真验证和热分析,证明了新的混合模式紧凑型盒型窗在34~52 GHz频带内平均功率容量达到10 k W、反射系数小于-18 d B、相对带宽超过40%.冷测实验结果证实了盒型窗在要求带宽内反射系数均小于-18 d B,能满足实际器件的指标要求     

W 波段回旋行波管高频结构设计和仿真*

对W 波段回旋行波管的高频结构的设计参数进行了分析计算与软件仿真,通过色散关系确定了磁场 取值,通过对返波振荡的分析确定了高频结构———周期衰减材料加载,通过对绝对不稳定性振荡的分析确定了工作 电流和横纵速度比的取值范围,最终得到了W 波段回旋行波管的工作参数。采用粒子模拟软件进行模拟计算,可以 得到155kW 的峰值功率输出和5.5GHz 的带宽,并给出了输出功率与回旋行波管各工作参数之间的关系曲线,进一 步证明了对返波振荡和绝对不稳定性振荡的分析与参数选取的合理性。实际加工的回旋行波管在测试中峰值功率 大于100kW,增益大于40dB,效率大于12%,3dB 带宽为4.1GHz。     

0.14 THz大功率回旋行波管前级激励源粒子模拟研究

以折叠波导行波管作为大功率回旋行波管的前级激励信号源,利用电磁仿真软件HFSS和粒子模拟软件(CST粒子工作室),对0.14 THz微电真空折叠波导行波管慢波结构的色散特性、耦合阻抗进行计算分析,然后对折叠波导行波管束波互作用过程进行粒子模拟,最后通过粒子模拟得到该折叠波导行波管的增益、工作电压、电流等工作特性参数。在电压为13.9 kV、电流为16 mA,输入功率为5 mW的条件下,输出功率为5 W,线性增益为30 dB,带宽3.7 GHz,最大输出功率为6.2 W,该结果为0.14 THz大功率回旋行波管实现kW量级的功率输出提供功率足够的前级馈入信号奠定了基础。     

0.14 THz折叠波导行波管盒型窗设计与制作

研究用于0.14 THz 折叠波导行波管的盒形窗结构,采用三维模拟软件 HFSS 进行计算与优化,设计出基于蓝宝石窗片的盒型窗结构.分析了结构参数对盒形窗电压驻波比的影响,主要结构参数在±0.01 mm范围变化时,盒形窗电压驻波比仍然低于1.2,保证零件加工的可行性.装配完成盒形窗测试结构,冷测结果显示,在0.135 THz~0.145 THz范围内衰减系数为0.7 dB左右,满足整管要求.     

利用MWS设计螺旋线行波管耦合结构

利用CST MWS仿真软件对螺旋线行波管耦合结构进行设计.首先,利用MWS仿真结果得出同轴线与螺旋线慢波结构连接部分的反射系数;接着,对高频窗进行了设计与优化;最后,计算出整个耦合结构可能产生的最大驻波系数小于2.0.对比理论值与冷测试数据表明,实测值小于理论计算的最大驻波系数.因此,在螺旋线行波管耦合结构的设计过程中,通过对驻波系数最大值的控制,可以满足实际工程的要求.     

0.22 THz折叠波导行波管盒型窗设计及实验

针对0.22 THz 折叠波导行波管设计了一款高频输入输出结构-盒型窗,并对其进行了理论分析和数值计算,通过 CST2010微波工作室和 Ansoft HFSS11进行模拟仿真验证。这种盒型窗不但降低了加工焊接难度,而且保证了较大带宽。本文得到了0.02 THz带宽,在0.21 THz~0.23 THz范围内反射系数都小于0.08。最终通过加工和实验测试对盒型窗进行了验证,实验测试和理论计算基本一致,满足了0.22 THz折叠波导行波管的需要。     

Electromagnetic Analysis and Cold Test of a Distributed Window for a High Power Gyrotron

A novel distributed window for output radiation from a high power 110 GHz gyrotron is made of thin slats of sapphire interleaved and brazed to hollow metal vanes. We report the results of electromagnetic theory and cold test of this distributed window. We calculate the frequency dependence of the reflectivity of a Gaussian beam from the window. The theory indicates a significant frequency shift of the minimum reflectivity with temperature rise of the sapphire slab. This effect is of great importance for high power operation. In cold test, the distributed window reflectivity was measured while the window was heated. The cold test results are in good agreement with the theory.     

白宝石窗口增透膜的研究

对白宝石 (Al2 O3)和石英 (SiO2 )窗口的性能进行了比较 ,并在白宝石上镀制增透膜 ,进行初步的判断实验 ,取得了良好的效果 ,同时对存在的问题进行了分析 ,指出白宝石是一种比较有前途的高功率激光窗口材料。     

The Study of a Millimeter to Submillimeter Wave Multiband High-Power Broadband Window

The theory of multilayer microwave window is investigated and applied to design a broadband high-power output window for a Q-band sheet beam traveling wave tube (SBTWT). The multilayer window consists of a c-axis sapphire disc (the geometry axis parallel to optical axis) in the middle and two identical matching quartz discs tightly attached on both sides. It presents a good multiband wideband and high-power performance from millimeter wave to terahertz range. The thermal property is analyzed and shows a more than 60 kW CW operating capability can be reached. The window is manufactured and cold tested shows a ?17 dB reflection bandwidth over 15 GHz (34%). The theory analysis, simulation, and cold test present a good consistency.     

A novel wide-band noise-parameter measurement method and its cryogenic application

The concept of using a long mismatched transmission line to measure noise parameters has been known for some time. However, it has been limited to narrow-bandwidth applications, and a wide-band extension has never been reported. In order to measure the cryogenic noise parameters of a wide-band low-noise amplifier (LNA), a wide-band frequency-variation method is proposed. In this method, the four noise parameters at each frequency are derived numerically from a set of matched and mismatched noise temperatures measured within a surrounding frequency-sampling window. By scanning this frequency-sampling window, noise parameters over a wide frequency range can be obtained. Since this approach can be easily incorporated into existing noise measurement systems, a tuner is not required, and the technique can be applied to a cryogenic amplifier. This paper details the theory, implementation, and verification of this new method. The measured noise parameters of a cryogenic wide-band LNA are presented.     

Cr:LiSAF slab laser performance

The performance of a flash-lamp pumped Cr³⁺: LiSrAlF ₆ multi-bounce slab laser is reported. The slab was conductively-cooled by a sapphire window which also transmitted the pump light. Laser output of 9 mJ and a slope efficiency of 0.061% were obtained although less than 15% of the total pump aperture was used     

Investigation of the sapphire window on short MM waves band

A analytic method of the eguivalent network for RF sapphire window of 3mm diffraction radiation oscillator is given in the paper. Numerical simulate and experiment are carried out on 3mm wave band. The testing results show that the design method agrees with the practical windows, and it is the fast optimum method. We employ the universal method, the piece of the window can be equal to dielectric waveguide and one end of the window connects the coupling slit of the mirror of open cavity. The design window by means of this method is used satisfactorily on 3mm DRO. The tube operates in the 84 – 108GHZ band, the output power is about 250mW.     

高超声速飞行器红外探测窗口辐射透射特性研究

高超声速飞行器在飞行过程中受到强烈的气动加热,位于头部的红外探测窗口温度上升显著,辐射透过率下降的同时自身发射辐射大幅增强,致使内部的红外探测器信噪比下降,严重情况下可能失效。对超声速弹头弹道末端蓝宝石红外探测窗口的气动加热-非稳态温升过程及其3.7-4.8μm波段红外辐射透射特性进行数值模拟,结果表明:平均温度已经不能准确反映蓝宝石窗口的红外透射特性及其对红外探测器灵敏度的影响;存在一个最优的红外探测窗口厚度,该厚度下红外探测器在弹道末端的灵敏度达到最佳。     

Millimeter Wave Measurement of the Low-Loss Dielectric in Vacuum Electronic Devices with Reflection-Type Hemispherical Open Resonator

Accurate dielectric properties are of great importance for the design and fabrication of the input and output windows in vacuum electronic devices. A reflection-type hemispherical open resonator (RTHOR) was designed through theoretical analysis and numerical simulation and also was utilized to measure the dielectric properties of the windows material sapphire. Compared with the two ports measurement, a simplified measurement system to obtain the dielectric performance was proposed and the RTHOR with only one coupling aperture was directly connected to a W-band vector network analyzer (VNA). The material properties can be easily calculated through the VNA measured port reflection coefficient (S₁₁) resonant curve. Investigation shows that the permittivity and the loss tangent of the measured sapphire, which is used to construct the input and output window, is respectively about 9.40 and 1.80?×?10^?4 at room temperature in W-band, which agree well with the reported results. Measured results also show that the simplified measurement system can provide a high accuracy for the measurement of low-loss dielectric in a relatively convenient way.