Q波段圆波导轴线弯曲TE01-TE11模式变换器设计

在模式耦合理论的基础上, 采用相位重匹配技术对圆波导轴线弯曲TE01-TE11模式变换器进行了数值优化计算和分析.在Q波段给出了两种不同周期数TE01-TE11模式变换器的优化设计参数.数值计算表明: 四周期模式变换器的最高转换效率为98.82%, 带宽为2.2 GHz, 六周期最高转换效率为99.89%, 带宽为1.7 GHz.研究了模式变换器关键几何尺寸在小范围内变化对转换效率的影响.并利用HFSS对给出的模式变换器进行了仿真, 仿真结果与数值模拟一致性较好.同时加工了六周期结构模式变换器并进行了小功率热测实验, 测试结果表明输出了模式纯度较高的TE11模式.     

回旋速调管TE01-HE11模式变换器

根据耦合波理论,编制了优化计算程序,优化了30.5GHz TE01-TE11模式变换器的几何结构,得到了其可实现最高模式变换效率的几何参量.用仿真软件优化设计了同一工作频率的TE11-HE11模式变换器.结果表明这两个模式变换器组成的TE01 -HE11复合模式变换器在30.5GHz和1％带宽内具有97.0％以上的TE...     

一种使用TE_(11)为过渡模的TE_(01)-HE_(11)模式变换器设计（英文）

基于弯曲圆波导耦合理论和规则圆波导突变结构模式匹配法,利用MATLAB软件编写的相关数值计算程序得到波导模式转换结构的优化参量,最终使用CST软件对模型进行了仿真和验证.该系统主要由三部分组成:一个TE_(01)-TE_(01)的过渡器,TE_(01)-TE_(11)和TE_(11)-HE_(11)的圆波导模式转换器.计算结果表明,该TE01-HE11模式转换系统在24.13 GHz的频率有5%的带宽、转换效率超过了99%.计算结果、仿真结果和实物冷测结果是一致的.     

圆波导TE01-TE11模式转换器设计与实现

基于耦合波理论的基础上,分析了TE01-TE11模式转换器的特性和半径渐变指数,讨论了中心轴线弯曲下的圆波导模式转换器,对中心频率33GHz的波导进行了模拟设计、仿真,在保证带宽的前提下,尽力降低转换器的长度和提高转换效率,最后达到了97．82％的转换效率,带宽达到2GHz。     

94 GHz TE_（02）-TE_（11）模式变换链的设计与模拟

本文在电磁场耦合模理论的基础上利用MATLAB优化工具对W波段回旋管用TE02-TE01-TE11模式变换链进行了详细研究与分析。应用编制的仿真程序对W波段TE02-TE01-TE11模式变换链进行了设计和数值模拟,通过结构参数优化,获得了性能良好的模式变换链。TE02-TE01和TE01-TE11模式变换器在中心频率94 GHz处的转换效率分别为96.3%和94.1%,对应带宽分别为4 GHz（转换率95%以上）和2 GHz（转换率90%以上）。为了进一步验证设计的模式变换链的性能,利用高频模拟仿真软件HFSS对优化的模式变换链进行了模拟仿真,模拟结果与利用计算程序得到的结果基本吻合。     

介质填充圆波导中TM01-TE11模式变换的理论和实验研究

提出了采用介质填充实现圆波导中TM01-TE11模式变换的方法,设计了中心频率为7.2GHz的圆波导TM01-TE11模式变换器,并进行模拟研究和实验研究.当介质材料采用聚四氟乙烯时,仿真结果表明:该模式变换器的最大转换效率为99.88%,转换效率大于90%的绝对带宽为0.71GHz;实验中测试到的S11参数与模拟结果基本一致,证明了该变换器技术方案的可行性和模拟结果的正确性.     

W 波段全带宽TE10-TE20模式转换器的研制

新一代W波段慢波结构行波管对波导TE10-TEn0 模式转换器的低损耗、宽带、转换效率等高性能方面提出了要求。 文中重点研究一款全W波段波导模式转换器的设计,实现E 面TE10 输入到H 面TE20 输出的模式转换,并结合高效率转换 结构,给出实际性能验证。首先,分析了波导TEn0 模分布特点,提出E 面功分结构、集成扭波导结构及H 面反相合成等单元 结构;其次,给出TE10-TE20 模式转换整体方案设计与电路优化;最后,结合H 面异相功分结构集成,基于计算机数控技术,实 现该W波段模式转换模块的制备,并完成三端口性能测试。实测结果表明,W 波段全带宽内(75 GHz~110 GHz),该TE10-TE20 模式转换模块输出端口功率分配比为-3.2 dB±0.2 dB,相位差为180°±2°,输入端口回波损耗优于-20 dB,且实测性能 均与仿真结果高度一致,验证了W波段宽带TE10-TE20模式转换器的高效率、低损耗、可行性及鲁棒性。     

径向双层介质加载圆波导的宽带TE_(11)-HE_(11)模式变换器

应用径向双层介质加载圆波导内可以产生混合模HE_(11)模式的原理,提出一种径向双层介质加载圆波导的宽带TE_(11)-HE_(11)模式变换器。在X波段分析了该变换器内微波模式满足的麦克斯韦方程和边界条件,推导出HE_(11)模式的特征方程及混合方程,最后将特征方程与混合方程联立,应用MATLAB软件进行数值求解得到物理模型的设计参数曲线。应用HFSS软件对设计的模式变换器进行模拟优化仿真,结果显示在8.40~10.16GHz频带内输出HE11模式纯度大于96%,最大为99.59%,相对带宽可达18.7%,理论功率容量达3.3GW。该圆波导TE_(11)-HE_(11)模式变换器具有结构简单、输入输出共轴、转换效率高、转换频带宽、功率容量高等优点,应用于微波辐射系统可以极大地提高辐射系统的紧凑性。     

同轴TE11模与矩波导TE10模的耦合计算

首先建立同轴TE11模与圆波导TE11模的等效关系。进而将同轴TE11模与矩波导TE10模的耦合问题转化为其等效圆波导TE11模与矩波导TE10模的耦合问题。实验证明,理论计算与实测结果吻合。     

Ku波段TE11–HE11光壁模式变换器设计

在耦合波理论的基础上,采用半径渐变、内壁光滑的结构实现TE11模到HE11模的变换,避免了传统的圆周开槽结构在高频段因加工产生的毛刺而导致容易打火的不足。提出一种由正弦与抛物线结合的结构曲线,通过数值计算设计了中心频率为15 GHz的回旋行波管TE11-HE11模式变换器,并利用电磁仿真软件进行对比验证。仿真结果与数值计算的结果一致性较好。设计的模式变换器带宽为1.2 GHz,相对带宽为8%,在15 GHz时的转化效率为98.5%。     

Optimized overmoded TE01-to-TM11 mode converters for high-power millimeter wave applications at 70 and 140 GHz

Mode coupling in bent, oversized, smooth-wall circular waveguides was studied by means of numerical integration of coupled-mode differential equations in order to optimize high-power TE01-to-TM11 mode transducers at 70 GHz and 140 GHz. Such mode transformers are used in the mode conversion sequence TEOn to TE01 to TM11 to HE11 for generating the almost perfectly linearly polarized Gaussian-like HE11 mode from circular electric TEOn gyrotron modes. This quasi-optical HE11 hybrid mode is in many respects ideal for electron cyclotron resonance heating (ECRH) of magnetically confined plasmas in thermonuclear fusion research and for other technical applications. Curvature and ellipticity coupling as well as ohmic attenuation of 6 coupled modes (TE01, TM11, TE11, TE12, TE21, TM21) are included in the coupling matrices. Integral expressions were used for deriving the coupling coefficients for arbitrary modes in bent, smooth-wall waveguide. Lowest level of unwanted spurious modes together with highest transmission efficiency (shortest arc length) is achieved with sinusoidal curvature distribution instaed of constant curvature. The calculated conversion efficiencies of 98.0% at 70 GHz and 95.2% at 140 GHz (interior waveguide diameter D=27.8 mm for 200 kW transmission lines) are in excellent agreement with the measured values of (97.6±0.4)% and (95±1)%, respectively.     

Design of mode converters for generating the TE11 mode from TM01 vircator at 4GHz

This work reports on measurements and calculations (coupled mode equations) on the conversion of transverse magnetic TM₀₁ vircator mode at 4 GHz to the linearly polarized TE₁₁ mode by means of mode converter systems using a circular waveguide with curvature. The mode converter is composed of a 38.78° bend with 39.07 cm curvature and a 50.78° inverse bend with 25.24 cm curvature in 9 cm internal diameter (ID) circular waveguide. The efficiency of conversion from TM₀₁ to TE₁₁ at 4 GHz exceeds 99%, and the overall efficiency from TM₀₁ to TE₁₁ exceeds 90% over a calculated range of 3.72–4.8 GHz.     

高功率毫米波模式变换中的相位重匹配

在模式耦合理论的基础上,对过模圆波导TM01-TE1模式变换进行了研究．采用不同的相位重匹配方法和选择相应的结构,对TM01-TE1模式变换器进行了优化分析,得出了圆波导半径、弯曲圆波导曲率和频率以及频带宽度之间的变化规律．以此结果可设计出相应的紧凑、高效、宽带毫米波过模圆波导模式转换器．     

High power millimeter-wave TE03 to TM11 mode converters

Transmission of power from 42 ± 0.2 GHz gyrotron (TE₀₃ mode) to tokamak or dummy load requires a set of transmission line components. It includes a set of mode converters that converts circularly unpolarised TE₀₃ mode to polarised HE₁₁ mode. The mode conversion sequence is methodised in two steps; first from TE₀₃ to TE₀₁ mode and then from TE₀₁ to TM₁₁ mode. The proposed mode converters performance depends on the parameters such as waveguide radius, beat wavelength, number of ripples, its perturbation amplitude (η) and bending angle. These parameters are numerically optimised and verified in CST microwave studio. TE₀₃ to TE₀₁ mode conversion is realised by the generation of intermediate mode TE₀₂. The mode conversion length for TE₀₃ to TE₀₂ mode converter is6λ₀, (where λ_b is the beat wavelength of corresponding mode conversion) which converts 99.15% of an incident circular TE₀₃ mode power into TE₀₂ mode power. Next, mode converter converts TE₀₂ mode into TE₀₁ mode with 99.06% efficiency along the optimal length of6λ_b. For TE₀₁ to TM₁₁ mode conversion, two conversion methodologies have been proposed: first using axis arc bend (34.94°) technique to convert TE₀₁ into its analogous degenerate mode with 99.01% conversion efficiency and second using parabolic curve with 90° bend, which gives a conversion efficiency of 97.5%.     

TE03 to TE01 mode converters for use with a 150 GHz gyrotron

Two-step high-power TE03-to-TE01 mode transducers (TE02 is the intermediate mode) were designed to transform the TE03 output mode of the 150 GHz KfK gyrotron into the fundamental circular symmetric TE01 mode for low-loss propagation and further conversion into the linearly polarized quasioptical HE11 mode. The advanced perturbation structures of the ruppled-wall mode converters (with input- and output-diameter D=27.8 mm) were optimized by numerically solving the proper coupled-wave differential equations. The overall TE03-to-TE01 conversion efficiency at 150 GHz was calculated to be η₀=99.1% for a long converter (total length L=2.67 m) and η₀=97.8% for a short converter (L=1.07 m); ohmic attenuation is included. The corresponding theoretical bandwidth (for η≧95%) is ±1.4 GHz and ±2 GHz, respectively. Low-power experimental data are in excellent agreement with these computed values.