采用“磁脉冲挤压法”组合降压收集极的新工艺

微波管中收集极要受到电子轰击而发热,如果散热不及时,会出现收集极内表面熔蚀。收集极的散热问题、绝缘问题以及降压问题要同时考虑。 降压收集极组件如果装配不紧密,收集极散热的效果就变差,导致大量放气,整管寿命缩短;挤压过紧则容易使陶瓷材料断裂,导致收集极的绝缘、耐压性能变差。 我们试验30多次,运用国际上先进的磁脉冲挤压法技术,并成功组合各类降压收集极40只。采用这种新工艺完全能够解决降压收集极组合的问题。     

一支新型降压收集极栅控脉冲行波管

正 本文介绍一支新研制的X波段、降压收集极、栅控脉冲功率行波管。该管采用大电流密度钪酸盐阴极和小型化钐钴PPM聚集。利用切断慢波线缩短了管长、提高了增益。采用新型散热措施,在3％的工作比下,输出功率达到千瓦级。用单栅,栅丝直径为0.025 mm,其电流截获率约为10％。采用单级降压收集极,降压度40％。电子注动态流通率约为95％,图1为降压收集极的实验曲线。试验管用的是活动收集极,其轴向位置可     

微型化四级降压收集极设计

介绍了一种微型化四级降压收集极的CAD正向设计过程。实测表明:该四级降压收集极的效率达到了75.3%以上,并具有良好的散热能力,CAD结果与实测值相吻合。     

焊接缺陷对行波管收集极温度分布的影响研究

行波管收集极焊接缺陷会影响其散热,严重时会导致行波管失效。利用有限元软件模拟计算了不同加载方式对行波管收集极温度分布的影响,研究表明两种加载方式下收集极内部温升差别较大。在静态加载的基础上,研究了焊接面积不足和焊接面积不均两种主要焊接缺陷对收集极温度分布的影响。分析结果表明,在用锡钎焊接收集极与底座时,除了要保证焊接接触区域在50%以上外,还要保证底座凹槽的侧边和底边与收集极都要接触良好。     

考虑次级电子的行波管多级降压收集极的辅助设计计算

文中较全面地讨论了多级降压收集极的物理模型.借助Orion(2.5维)软件设计出效率较高的带有再聚焦系统的四级降压收集极,并考虑了次级电子的影响,模拟计算多级降压收集极和再聚焦区的性能,为行波管整管效率的提高提供了保证.     

一种大功率高效率正交场放大管

本文陈述了提供大功率注入式电子注正交场放大管高板极效率的设计概念。这些概念在一只低负载、5千瓦、S波段注入电子注正交场放大管中得以实验验证。放大管设计成能以连续波工作,采用传导或者冷却液冷却。放大管采用极宽的互作用线路(卡普“Kar-P”线路)。效率好的十级降压收集极结合高线路效率,导致板极效率大于65％。并且也陈述了限制电子注电位作为增高互作用效率和简化收集极电源的一种技术。     

导热绝缘胶的研制和应用方法

讨论了导热系数ｋ与材料本身相联系的因素,以树脂、固化剂和导热绝缘填料的选择组合处理上进行了试验,取得了性能优异的导热绝缘的配方,结合具体的器件与散热构件的组合进行了讨论,取得了良好的散热效果,解决了一些问题。     

多级降压收集极行波管高压电源的设计

为了提高真空管雷达发射机的效率、缩小整机的体积和重量,常使用多级降压收集极行波管作为功率射频放大器.为了保证多级降压收集极行波管高增益、高效率和良好线性等性能发挥的更好,就要在行波管每个电极上加合适的电压,确保行波管内建立稳定的电场.因此,根据行波管各电极的特性合理地选择各收集极的电压以及合理的设计高压电源显得尤其重要.文中结合多级降压收集极行波管的工作特性介绍了4种高压电源的设计方法及其特点.     

改进速调管效率的十级静电降压收集极

在一只1千瓦连续波750兆赫速调管上测试了一个十级静电降压收集极,它是借助于模拟计算机进行设计的。在不同的高频激励情况下,计算和测量的性能达到良好地一致。利用降压收集极,在高频满功率输出情况下,经能量交换的电子注的能量中的60％可得以回收。管子的纯功率转换效率以未降压时的54.3％上升到约为70.9％。在二分之一满功率输出情况下测得收集极效率为70％。在零高频功率输出情况下,收集极效率是80％。为了达到上述结果,需要在最后漂移管和收集极之间装置一个小型的聚焦线包。当采用收集极降压时,没有发现寄生振荡或不稳定性,电子返转也未大量增加。相邻一对收集极的内部短路,仅使收集极性能略微降低。     

微型多级降压收集极的电、热及动力学优化设计

介绍一种对行波管中使用的微型多级降压收集极进行电、热及动力学优化设计的系统方法,同时期望这样一种方法能够移植到行波管其他部分的设计优化中。优化所得的收集极在全频带上的仿真效率达到79.5%以上,其散热能力满足环境要求,热裕量充分,并且结构强度远超环境需要。     

Three-dimensional simulation of multistage depressed collectors onmicro-computers

A three-dimensional (3-D) package for simulation of asymmetric and crossed-field multistage depressed collectors for microwave tubes has been developed. This package is based upon the 3-D finite-difference code KOBRA3-INP. The main features of the package are a user-friendly input interface, post-processors for collector analysis and calculation of secondary electron trajectories, and versatile output graphics. Both PC and mainframe versions of the package have been developed. The results of simple benchmark tests and those of simulation and analysis of asymmetric and crossed-field collectors including the effects of secondary electrons are presented. It is found that the asymmetric hyperbolic electric field collector shows very low backstreaming. It is shown that the representation of trajectories in energy space gives a better insight into the behavior of individual trajectories than plotting in coordinate space. The package will be useful for designing novel types of depressed collector     

A new type of depressed collector using a magnetic field†

A new form of depressed collector for microwave tubes has been investigated. It is shown that the use of a suitably selected transverse magnetic field in the collector leads to a smoothing of the power dissipation curve on the collector walls and to a fifty-fold reduction in the returning secondary-electron current.     

e-Guns and depressed collectors for two-stage free electron lasers

Ane-gun, depressed collector, and guide-field solenoid have been designed and tested for operation at a maximum of 400 kV and 38 A in order to simulate key components of a typical low-voltage free electron laser (FEL). Detailed beam-energy-spread analyses and computer simulations are presented for thee-gun and the drift regions. The results of experiments with the depressed collector show beam-current-recovery efficiencies of over 90 percent fore-beam voltages from 160 to 400 keV. We have also set up and confirmed computer-code predictions that a space-charge depression in the collector (which is essential for efficient collection) forms at a collector-voltage setting of 1 percent of the beam voltage. These results demonstrate the validity of substantially increasing the efficiency of systems by using depressed collectors to recover the bulk of the energy which is left in thee-beam after it leaves the laser resonator. The recovery-efficiency parameter (recovered current/cathode-emission current) is shown to be a function of the relativistic-orbit parameter (B/betagamma) and reaches a maximum of 94 percent. These results imply that FEL system efficiencies can be achieved which are an order of magnitude higher per stage than would be possible without the use of depressed collection.     

Effect of collector voltage and collector current on junction temperature

Experiments have been carried out on the 2N929 transistor to investigate the effect of collector voltage and collector current on junction temperature. The results indicate that at constant power dissipation increasing the collector voltage will increase the junction temperature and give the apparent effect of a higher thermal resistance.     

Improvement of traveling-wave tube efficiency through collector potential depression

This paper describes the design of single-stage and double-stage collectors which can be operated at "depressed" potentials. When these single-stage and double-stage collectors were used in conjunction with a traveling-wave amplifier, over-all efficiences of 46 and 57 per cent were obtained, respectively. The maximum increase in efficiency which can be obtained by the use of depressed collectors having one to three electrodes is calculated for various traveling-wave tube design parameters.     

电力电子设备常用散热方式的散热能力分析

本文对电力电子设备中常用的风冷和水冷两种散热方式的散热能力作了综合分析。分析结果表明,以散热器底面热源的均匀热流大小作为散热能力的标准,在保证电子设备正常工作的条件下,有散热空间限制时,风冷系统散热极限约为40W／cm2,如果不受散热空间的限制,散热能力会更高。水冷系统的散热能力比风冷系统高出1到2个数量级,其散热潜力还未得到充分挖掘,目前水在微通道内强制对流的冷却方式是水冷系统中具有最大散热能力的方式,其散热能力可达790W／cm2。这两种冷却方式散热能力的分析结果可作为热设计人员选择经济合理的散热方式的依据。．     

一种应用于Ku波段脉冲行波管的两级降压收集极的研究

本文介绍了一种应用于Ku波段脉冲行波管的两级降压收集极的研制结果,应用了该两级降压收集极的Ku波段脉冲行波管的总效率已经达到40%以上。     

D波段行波管三级降压收集极的设计

效率是行波管(TWT)的重要技术指标,为提高某一0.22 THz折叠波导行波管的效率,需设计多级降压收集极。对注波互作用后的电子注信息进行分析,估算收集极效率最高时的电压设置。利用电磁仿真软件对三级降压收集极电极结构和电压设置进行仿真优化,得到效率大于87.5%,回流电流小于0.328 9 mA的轴对称三级降压收集极;在第二电极入口采用斜口结构进行仿真优化,得到回流电流小于0.075 mA的非轴对称三级降压收集极。结果表明,采用斜口结构可以有效降低0.22 THz行波管多级降压收集极的回流电流。     

Prototype constant-efficiency amplifiers

This paper describes two constant efficiency amplifiers (CEA) using cathodes, novel grids and novel cavities similar to those used in our inductive output tubes together with five-electrode, multi-stage, depressed collectors in either poly alpha olefin (PAO) oil-cooled or forced-air-cooled versions. The air-cooled version is capable of 65 kW peak 8VSB or COFDM operation, and the oil-cooled tube will provide the performance of our higher power IOTs in either 8VSB, COFDM or NTSC service with much higher average efficiency. The PAO oil (similar to synthetic automobile engine oil) is a low-cost coolant that simultaneously solves insulation and corrosion problems. These tubes meet the expectations that were discussed in our previous papers. The design and performance are described together with application data useful to transmitter designers. Collectors may be connected together to minimize the number of independent voltages required or operated independently to maximize efficiency and minimize power supply size for a wide variety of signal statistics. A single thyratron crowbar circuit which will simultaneously short circuit up to five voltage sources is described. The CEA design and its application are covered by US and foreign patents issued and pending. Adoption of this technology will save television broadcasters in the order of one billion dollars of electrical power cost over the life of these patents