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。     

新型大功率水负载的微波和流体设计

为了测试从法国Thales公司购买的频率为3700MHz,以连续波模式运行的TH2103C型速调管,提出了一种新型大功率水负载来吸收其单路高达375kW的庞大功率,采用陶瓷片隔开去离子水,再由后者吸收微波功率,所设计的水负载在超过100MHz带宽内驻波比小于1.1;经流体分析、仿真及优化,在高平均功率注入的情况下,微波在水体中产生的热馈能迅速地被水流带出高压水箱;陶瓷片所受水体的压力也在其机械强度允许范围之内,满足测试新型速调管的要求.     

Ku波段螺旋波纹波导回旋行波管色散特性研究

为抑制回旋行波管的自激振荡和增加回旋行波管带宽,俄罗斯G.Denisov等人提出一种新型回旋行波管结构——螺旋波纹波导回旋行波管。通过螺旋波纹波导的特殊结构使通过波导的两种模式发生耦合,耦合出一种新的工作模式,从而改变色散特性,达到抑制自激振荡和增加带宽的目的。通过螺旋波纹波导的色散方程,分析其色散曲线,从而分析螺旋波纹波导作为回旋行波管高频系统的优势。     

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。     

大功率行波管在ECM系统中的应用

概括介绍了行波管的产生和基本原理，以及大功率行波管在ECM系统中的使用方法及注意事项。最后简要说明了如何利用功率合成技术使用4只kW级行波管成功的获得4kW的连续波超大功率。     

X波段大功率PPM聚焦耦合腔行波管的研制

本文概述了国内外X波段大功率行波管的技术现状,介绍了某X波段大功率周期永磁聚焦耦合腔行波管的设计和测试结果,该行波管在X波段800 MHz带宽内的平均输出功率大于5kW、效率大于42.5%。     

0．22THz准光波导回旋返波管的设计与模拟研究

回旋返波管作为一种频率可调谐的大功率太赫兹辐射源器件,具有较好的实用前景。本文根据回旋返波管线性理论设计了一只中心工作频率在0．22THz的准光波导回旋返波管,采用自主研发的三维粒子模拟软件CHIPIC对其进行数值模拟研究,分析其工作特性。仿真结果表明：所设计的回旋返波管可获得14kW的峰值功率输出,输出功率大于5kW时调谐带宽大于1GHz。     

Ku 波段回旋行波管设计与分析

设计了用于Ku波段的介质加载回旋行波管。阐述了磁控注入电子枪的设计,采用均匀介质加载的结构来抑制回旋行波管的自激振荡,降低了回旋行波管的起振电流,同时提高了寄生模式的起振长度。设计了线极化输入耦合器。设计的回旋行波管工作电压为70kV,工作电流为10A,最大峰值功率210kW,最大功率处增益为35dB,3dB带宽为1.8GHz。     

耦合腔行波管

几年来,贵州凯里国营宇光电工厂对耦合腔行波管的研制和试用方面作了大量工作。他们从理论计算、制管工艺,抑制自激振荡方面进行探讨,找到了有效的抑制方法,取得了较满意的结果。成功地研制出了X波段水冷式周期永磁聚焦耦合腔行波管(见图1),其输出功率大于25kW,瞬时带宽达12％,增益大于32dB、工作比为0.5％。后又根据用户要求、研制出更高频率的风冷式耦合腔行波管系列(见图2),其输出功率分别为10kW和15kW,瞬时带宽为10％、增益大于33dB、工作比为1％。     

螺旋线毫米波行波管及宽带毫米波功率模块的研制进展

本文介绍了中国电科12所K、Ka波段螺旋线行波管及毫米波功率模块研制进展情况,包括宽带行波管及毫米波功率模块,大功率通信/雷达用行波管、幅相一致行波管。目前已实现Ka波段小型化的宽带行波管及毫米波功率模块输出功率大于160 W;Ka波段幅相一致行波管相位一致性达到±25°;大功率毫米波行波管已形成系列化产品。     

Ka-band resonant ring for testing components for a high-gradient linear accelerator

A new millimeter-wave resonant ring using a traveling TE/sub 01/ wave in an oversized cylindrical waveguide has been developed for high-power tests of accelerator components. Novel low-loss miter bends with flat mirrors that utilize mode mixing to minimize losses were used in the resonant ring. Low-power measurements show a maximum effective power gain factor that exceeds 35:1 at the operating frequency of 34.272 GHz. Total quality factor is approximately 21400, and the reflection coefficient from the input to the ring resonator is less than 1%.     

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.     

System Development and Performance Testing of a W-Band Gyrotron

A high-power W-band gyrotron has been designed and performance tested in Korea, with an output power in the range of tens of kilowatts. The gyrotron consists of a diode-type electron gun operating at 40 kV, a TE6,2 mode interaction cavity, and a mode converter for producing a highly Gaussian output mode beam. Presented here are the detailed component design procedure and the experimental results of the gyrotron’s performance evaluation. A maximum power of 62 kW was achieved with an efficiency of 22 %, and a highly Gaussian output beam was observed. The gyrotron’s output beam is analyzed, and its transmission through an oversized waveguide is discussed. This gyrotron is the first gyrotron developed in Korea with high power greater than 10 kW and high frequency greater than 90 GHz.     

HT—7托卡马克ECRH系统传输线设计

给出了用于HT-7超导托卡马克聚变实验装置的电子回旋共振加热（ECRH）系统大功率毫米波传输线的设计，该传输线将回旋管输出的频率为60GHZ，峰值功率200KW，脉冲宽度不大于100ms的毫米波传输数十米，在传输过程中将最初的TE02波转换为TE01波，再进一步转换至准线性TE11波，最终通过准光学天线将该毫米波以一定的角度发射到托卡马克等离子体中。     

Characteristics and Optimum Operating Parameters of a Gyrotron Traveling Wave Amplifier

Characteristics and optimum operating parameters are determined for a new type of high-power high-efficiency generator of millimeter waves known as a gyrotron traveling wave amplifier. In the example consided, wave amplification results from the interaction of a TE/sub 01/ waveguide mode with the fundamental cyclotron harmonic of an electron beam. The parameter optimization involves the determination of the point of maximum device efficiency as a function of beam density, beam energy, beam positioning, and external magnetic field for the output power required. An analytical linear theory and a numerical simulation code form the basis of theoretical calculations. As a result of the extensive survey in parameter space, the peak efficiency in the beam frame has been found to exceed 70 percent. This result has been applied to the specific design of a 35-GHz amplifier with output power ~340 kW, a power gain of 2 dB/cm, and a laboratory frame efficiency of 51 percent.     

Spatial and Temporal Coherence of a 35-GHz Gyromonotron Using the TE/sub 01/ Circular Mode

The characteristics of a 35-GHz oscillator operating with the TE/sub 01/ circular waveguide mode are described. The device produced 147 kW, with an efficiency of 31 percent at 100 kW. The total radiated energy was 2 kJ/pulse. The spectral coherence appears to be equal to those of other high-quality microwave tubes. The mode purity is greater than 95 percent.     

介质加载圆柱腔的场分析

本文应用严格场匹配法解决了介质加载圆柱腔的本征问题，计算了圆柱腔在纵向部分填充介质后ＴＥ０１ｎ模和ＴＭ０１ｎ模的本征频率和本征场型的变化。特别分析了本征模式在空气段为截止模的情况。本文的分析方法亦可应用到纵向部分填充介质的传输线和其它形状的谐振腔。     

高功率微波混合模式辐射特性的初步研究

通过阐述模式识别的重要性及其在高功率微波中的特殊性，论证了利用辐射特性来识别模式的可行性，并以某金属截面圆波导为例，通过纯解析、半解析、数值模拟三种方法对其中的TE11和TM01混合模式辐射场分别进行计算和分析，得到基本物理图像和特征，实验结果为模式判别提供了初步判据。     

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.     

Gyrotron-traveling wave-tube circuits based on lossy ceramics

The gyro-traveling wave tube (gyro-TWT) is a microwave amplifier with simultaneous high power, high frequency, and broad bandwidth capabilities. Techniques for providing a controlled loading of the TE/sub 01/ cylindrical-guide operating mode of a 35 GHz gyro-TWT using monolithic, lossy ceramic structures are presented. The loading scheme, which also suppresses spurious backward-wave oscillations in the TE/sub 11/, TE/sub 21/, and TE/sub 02/ modes, is based on a sequence of alternating ceramic cylindrical shells and metal rings to form the electron beam tunnel. Design techniques for achieving optimal performance and methods for reducing the sensitivity to temperature-induced variations in ceramic dielectric properties are presented.