Q波段回旋行波管新型盒型输出窗的设计

利用等效电路理论,初步设计了窗片厚度为1.32 mm的回旋行波管盒型输出窗,再加入感性膜片,更改窗片形状,最终设计出了能承受25 kW平均功率、相对带宽达到14%、窗片厚度达到1.7 mm的Q波段新型宽频带回旋行波管盒型输出窗;采用高频软件HFSS与有限元分析软件ANSYS协同仿真的新方法对回旋行波管盒型窗进行热特性研究表明,盒型窗理论上功率容量达到62 kW平均功率,说明输出窗窗片承受25 kW平均功率的可行性,窗片中心与边缘的温差为66 ℃,没有达到陶瓷窗片的临界温差158 ℃,验证了新型盒型窗设计的合理性。     

Q波段回旋行波管新型盒型输出窗的设计

利用等效电路理论,初步设计了窗片厚度为1.32mm的回旋行波管盒型输出窗,再加入感性膜片,更改窗片形状,最终设计出了能承受25kW平均功率、相对带宽达到14%、窗片厚度达到1.7mm的Q波段新型宽频带回旋行波管盒型输出窗;采用高频软件HFSS与有限元分析软件ANSYS协同仿真的新方法对回旋行波管盒型窗进行热特性研究表明,盒型窗理论上功率容量达到62kW平均功率,说明输出窗窗片承受25kW平均功率的可行性,窗片中心与边缘的温差为66℃,没有达到陶瓷窗片的临界温差158℃,验证了新型盒型窗设计的合理性。     

波导型高功率微波输能窗的研究进展

波导型高功率微波输能窗是高功率速调管和高能粒子加速器的关键部件,输出窗高频击穿是引起高功率速调管失效的一个重要因素。综述了国内外电真空领域波导型输能窗的研究进展,介绍了传统盒型窗的研究现状、工艺要求和击穿机理;介绍了锥型窗、行波窗、复合模窗以及过模窗等新型输能窗的设计特点,给出了改变窗片材料属性、改变窗片表面形态、窗片边缘倒角、外置直流电场/直流磁场、改变信号波形等击穿抑制技术的研究进展。     

L波段大功率全带宽波导盒型窗

 由于鬼模振荡的存在,普通波导盒型窗很难获得宽频带输出,其相对带宽一般只有20%～30%。提出一种新的适用于大功率螺旋线行波管非对称全带宽波导盒型窗设计思路,通过３维电磁仿真设计与优化,获得了L波段相对带宽达41.4%盒型窗结构设计参数,且频带内无鬼模振荡,考虑匹配过渡段后整个盒型窗驻波系数模拟计算小于1.1。采用此功率输出结构研制的S波段大功率行波管连续波输出功率达3 kW以上,整管实测驻波系数小于1.6。     

高功率盒形窗内次级电子倍增效应

以S波段高功率盒型窗为对象,采用Monte Carlo模拟方法对盒型窗内的次级电子倍增效应进行研究,探索次级电子的倍增规律。模拟得到了盒型窗内TE11模和TM11模共同作用下,两种陶瓷窗片表面次级电子倍增活跃的区域随传输功率的变化特点。在低传输功率下,次级电子仅在未镀膜窗片表面被激励,并以双面倍增的方式在金属法兰与镀膜窗片相对应的区域增长;在较高的传输功率下,窗片表面的次级电子将以单面倍增的方式活跃在窗片表面与波导口相对的区域。传输功率的升高使得镀膜窗片表面的次级电子倍增活跃区域转移到矩形波导窄边对应的区域,并加剧了未镀膜窗片表面的局部倍增效应。     

高功率盒形窗内次级电子倍增效应

以S波段高功率盒型窗为对象,采用Monte Carlo模拟方法对盒型窗内的次级电子倍增效应进行研究,探索次级电子的倍增规律。模拟得到了盒型窗内TE11模和TM11模共同作用下,两种陶瓷窗片表面次级电子倍增活跃的区域随传输功率的变化特点。在低传输功率下,次级电子仅在未镀膜窗片表面被激励,并以双面倍增的方式在金属法兰与镀膜窗片相对应的区域增长;在较高的传输功率下,窗片表面的次级电子将以单面倍增的方式活跃在窗片表面与波导口相对的区域。传输功率的升高使得镀膜窗片表面的次级电子倍增活跃区域转移到矩形波导窄边对应的区域,并加剧了未镀膜窗片表面的局部倍增效应。     

金属壁与介质窗之间次级电子倍增效应的研究

高功率盒形窗内的TM11模法向电场对次级电子倍增现象具有较大的影响,特别是在介质窗片与金属波导壁相对的区域,易发生双面次级电子倍增.采用蒙特卡罗粒子模拟方法,研究了法向电场作用下氧化铝陶瓷窗片与铜波导壁之间的双面倍增敏感曲线、倍增阈值电压、粒子数量的演变过程以及粒子运动轨迹.通过对相关参数的分析,获得了金属壁与陶瓷窗片之间双面谐振倍增和非谐振倍增的规律以及双面倍增向单面倍增转变的特点.此研究可为分析窗片失效机理提供理论依据.     

A fast computational technique for RF window in millimeter wave tubes

RF Window of millimeter wave tubes becomes very thin because of extreme high frequency, so that power capacity of the window is limited, manufacturing is difficult and it easy leaks. The equivalent circuit and computation are given for a type of ceramic block RF window with compensating irises. This RF window has higher power capacity, compact mechanical strength, easy manufacturing and airtight welding. The testing results show that the design method is fast and useful accuracy.     

刻周期半圆弧槽窗片对次级电子倍增效应的抑制

为了抑制高功率盒形窗内的次级电子倍增效应,研究了一种刻周期半圆弧槽窗片结构. 通过对槽内电场进行分析,证明了半圆弧状槽可以有效避免尖锐边界的局部场增强效应. 利用蒙特卡罗随机算法对槽内的次级电子倍增效应进行数值模拟,跟踪次级电子的轨迹及发展趋势,获得了不同槽宽所对应的抑制次级电子倍增最低电场强度. 讨论了法向电场对半圆弧槽抑制次级电子倍增的影响. 该结构有望在高功率速调管中获得应用. 关键词： 盒形窗 半圆弧槽 次级电子倍增 蒙特卡罗模拟     

Investigation for Arcing Phenomenon in High Power MW/MMW Tubes

The arcing phenomenon in high voltage is one of the main failure modes for high power microwave and millimeter wave (MW/MMW) tubes. According operating principle of vacuum electronic devices, the factors of leading the arcing are discussed and the approaches for eliminating the arcing phenomenon are given in this paper. The theoretical and designing foundation raising the reliability for MW/MMW tubes are provided.     

The research of optical windows used in aircraft sensor systems

The optical windows used in aircrafts protect their imaging sensors from environmental effects.Considering the imaging performance,flat surfaces are traditionally used in the design of optical windows.For aircrafts operating at high speeds,the optical windows should be relatively aerodynamic,but a flat optical window may introduce unacceptably high drag to the airframes.The linear scanning infrared sensors used in aircrafts with,respectively,a flat window,a spherical window and a toric window in front of the aircraft sensors are designed and compared.Simulation results show that the optical design using a toric surface has the integrated advantages of field of regard,aerodynamic drag,narcissus effect,and imaging performance,so the optical window with a toric surface is demonstrated to be suited for this application.     

A Fast Computation of the Start-Oscillation Current of Backward Wave in MMW HTWT's

Backward wave oscillation can be troublesome in high power helix TWT, especially millimeter wave helix traveling wave tubes (MMW HTWT's). To suppress these oscillations, start-oscillation current of backward wave has to know when MMW HTWT's are designed.A fast computation of the start-oscillation current for MMW HTWT's is presented. It is shown that the computed values are agreed with the experimental results in Ka band.     

Design of a tapered helix for suppressing backward wave oscillations in MMW TWT’s

Backward wave oscillations are easy occurred in high power helix millimeter wave traveling wave tubes (MMW TWT’s), owing to larger ka value and higher operating voltage. The start current of backward wave is calculated for helix TWT in Ka band. It is shown that start current will increase by used a tapered helix. Backward wave oscillations can be suppressed in tube. The design method of the tapered helix is given in this paper.     

A RF window for broadband millimeter wave tubes

The equivalent circuit and design method for a RF window in millimeter wave band are presented. Computation and experiment show that matching band of the RF window is wider. It can be used as output window for broadband millimeter wave tubes.     

放射性核素寿命计算方法的模拟研究

根据几种常用放射性核素的寿命计算方法,通过模拟数据研究了直接拟合法、对数时间法、极大似然法、观测时间受限时的极大似然法等四种寿命计算方法的适用范围。当观测时间不受限时,研究了在不同计数下寿命计算方法的适用范围。当观测时间受限时,研究了在不同观测时间窗口下寿命计算方法的适用范围。模拟中选用全剥离离子94mRu44+作为目标核素,得到了不同计数及不同观测时间窗口下的寿命及其误差,并给出了四种方法的适用范围。94mRu44+寿命的模拟结果与在兰州等时性质量谱仪上获得的实验结果在一倍标准偏差范围内一致,从而进一步验证了寿命计算方法的适用范围及模拟数据的可靠性。该模拟结果可为寿命测量实验设计提供理论依据和参考。     

Research of a sphere–cone window with good aberration characteristic

Optical windows with external surfaces that shaped to satisfy operational environment needs are known as special windows. A novel special window, sphere–cone (SC) window, is presented. The equations used to decide geometrical parameters of this window are deduced. A SC MgF₂ window with a fineness ratio (F) of 1.33 is designed as an example. The field-of-regard (FOR) angle is ±80°. From the window system simulation results by the calculated fluid dynamics (CFD) and optical design software, we find that the SCP shape compared to conventional window forms not only introduces relatively less drag in the airflow, but also makes the minimal effect to imaging. After a correcting lens is adopted in the SC window optical system, the lowest modulation transfer function (MTF) value at 17 Lp/mm reaches 0.610 and the root-mean-square (RMS) spot size is approximately 1.57–2.12 times than the diffraction limit. The design results show that the SC window optical systems can achieve high image quality across very wide FOR by the simplest static correction.     

Analysis of Transmission Characteristics for Single and Double Disk Windows

The work reports about window design studies for both the JET EP ECRH project and the ASDEX-Upgrade ECRH system. Detailed calculations of the millimeter wave transmission characteristics for conventional single-disk windows, for frequency tunable double-disk windows and for ultra-broadband Brewster windows have been performed. The geometry of the window units has been optimized in order to obtain a suitable transmission characteristic, i.e. power reflection less than –20 dB within a frequency bandwidth of about 1 GHz around the chosen frequencies. In particular the influence of mechanical tolerances on the transmission characteristic has been investigated in order to specify the mechanical dimensions of the CVD-diamond disks and the window unit. In case of a Brewster window, the thickness has been optimized to get low power reflection over a wide angles range around the Brewster angle.     

动态库在像管设计中的一种应用方法

本文对像管设计及优化设计中动态链接库的使用进行了探讨，论述了动态连接库使用的常规方法，并针对像管优化设计的特点，提出了一种Ｗｉｎｄｏｗｓ环境下动态链接库使用的较佳方案。此方案可应用于其它领域，如光学的系统设计等。     

High-birefringence hollow-core anti-resonant THz fiber

A novel high-birefringence hollow-core anti-resonant THz fiber is proposed in this paper. This fiber has a simple structure which consists of only ten Topas tubes. High birefringence is achieved by introducing two large tubes. The first two resonant frequencies are 1.44 and 2.88 THz by fixing tube thickness at 0.09 mm, which makes two low-loss transmission windows exist in the frequency range from 0.8 to 3.0 THz. The lowest loss is 2.10 dB/m occurring at 1.2 THz in the first transmission window and 1.68 dB/m at 2.34 THz in the second transmission window. By optimizing the structure parameters, high birefringence above 7 × 10^?4 in the frequency range from 1.0 to 1.24 THz are obtained. The highest birefringence is up to 8.7 × 10^?4 at 1.04 THz. Birefringence can be further increased to the order of 10^?3 by adjusting the structure parameters at the cost of loss increasing and the bandwidth decreasing. In addition, bent performance of this fiber is also discussed. In addition, this fiber can keep good performance when it is bent for x-direction. At the bend radius of 15 cm, the loss and birefringence has a more slightly change in the first transmission window than the second transmission window. The first transmission window own much better bent-insensitive characteristics.     

特殊光学元件的新型子孔径拼接检测方法研究

使用新型的特殊整流罩窗口可以明显地提升飞行器的空气动力学性能,但由于这种共形窗口光学表面的复杂性,传统的非球面检测技术已经较难满足要求.本文提出了一种新型子孔径拼接检测技术,在建立新的检测原理基础上,还重点介绍了这种检测方法的设计.同时基于补偿法的原理,文中还针对一个口径70 mm的共形窗口,设计了相应的特殊补偿器,其最终剩余波像差(RMS)为0.0515λ(λ=632.8 nm),可以满足实际使用要求. 关键词： 共形窗口 共形检测 子孔径拼接检测 补偿器