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行波放大管是近20年来所研制的比较重要的微波器件之一,广泛运用在需要把1000～10,000兆赫高频讯号放大的雷达、导航和通讯系统中。然而,一直到五年前行波管仍被认为是不可靠的,因而其应用局限在地面和机载系统中,因为在这些系统中行波管能够定期地更换。随着宇宙飞船和深空探测所需要的宇宙通讯的出观,需要一种坚实、重量轻的中功率微波放大管,这种管子不会影响飞船可靠性或寿命。在宇宙飞行环境中,微波放大管是不可能维修的,而用备份也不是解决可靠性的办法。所以,微波放大管所需的寿命须包括储存时间和工作时间,而到损毁时的平均时间(MTTF)则应与工作性能指标一致。本文叙述由休斯公司微波管分部所采用的一种解决达种行波管设计的成功的方法,用此法设计的行波管满足了宇宙航行大部分要求。运用这种方法设计的一族宇宙飞行用行波管,可认为是宇宙飞船的最可靠的组成部分之一。所有保证可靠性的现代技术都用于此行波管。它们包括损坏形式的分析,生产部件的控制和检查,选择和老炼,环境试验,制造和试验操作的严密控制。虽然行波管的工作原理简单,但由于存在着许多难以确定的损毁机理,从可靠性的观点考虑,这种器件又是复杂的。本文详细讨论损坏形式和机理及其控制方法。着重叙述可靠性与优良的工作性能相结合的机械结构,采用长寿命阴极—热子设计,选择材料和制造工艺。以上每一项都有助于达到超高可靠性和长寿命。由许多中功率行波管实验计划所提供的数据证明,达种设计方法是成功的。休斯公司设计的一般宇宙用行波管,在寿命试验和字宙飞行中已累积了大于800,000小时的寿命。
Traveling wave amplifier tube is one of the more important microwave devices developed in the past two decades. It is widely used in the radar, navigation and communication systems that need to amplify the high frequency signals from 1000 MHz to 10,000 MHz. However, TWTs were still considered unreliable up to five years ago, so their applications are limited to terrestrial and airborne systems because TWTs can be regularly replaced in these systems. With the advent of cosmic communications needed for spacecraft and deep space exploration, there is a need for a solid, lightweight medium power microwave amplifier that does not affect spacecraft reliability or life expectancy. In the space flight environment, microwave amplification tube is impossible to repair, and use the backup is not the solution to the reliability. Therefore, the life of the microwave amplifier tube must include the storage time and working time, and the time to failure (MTTF) should be consistent with the performance indicators. This article describes a successful solution to the design of traveling wave tube used by Microwave Division of Hughes. The traveling wave tube designed by this method satisfies most of the requirements of space flight. A family of spacecraft traveling wave tubes designed in this way can be considered as one of the most reliable components of a spacecraft. All modern technologies that guarantee reliability are used for this traveling wave tube. They include analysis of the forms of damage, control and inspection of production components, selection and aging, environmental testing, tight control of manufacturing and testing operations. Although traveling wave tubes have a simple working principle, the device is complicated from the point of view of reliability due to the existence of many hard to determine damage mechanisms. This article discusses in detail the form and mechanism of damage and how to control it. Emphasis is placed on the mechanical structure that combines reliability with excellent workability, long-life cathode-hot sub-designs, materials selection and manufacturing processes. Each of the above helps to achieve high reliability and long life. The data provided by many of the medium-power TWT pilot programs demonstrate that a successful design approach is successful. Hughes designed the general cosmic traveling wave tube, which has accumulated more than 800,000 hours of life in life tests and cosmic flights.