European Space Agency

Very High Power S-Band


The objective is to develop a new travelling wave tube with the output power of 500W. The output power is double that of today’s products. Key issues are the higher dissipation power and to have as much margin as possible for multipaction in the output section. Another objective is to retain as much heritage from today’s travelling wave tubes respecting the specified typical space requirements based on twice that of today's rf power.

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  • Achieve the output power,
  • Handling the dissipation power,
  • Achieve a good margin for multipaction in the rf output,
  • Achieve a good thermal contact,
  • Keeping the standard requirements (electrical, mechanical and thermal).


The new travelling wave tube is a consequent enhancement of the THALES product portfolio for high power S-Band TWTs. Based on solutions known for their long heritage, a high reliability is expected once the development reaches the final state.


Generally a travelling wave tube consists of 4 parts, these being the gun, the line, the collector and the housing.

Inside the gun the electron beam is generated and pre-formed to be injected into the line. In the input section of the line the electrons are packaged corresponding to the RF input signal. In the output section the RF signal is amplified. Finally the electron beam reaches the collector with different stages for different velocity of the electrons. Here the main dissipation power is generated. The fourth component, the housing, is to ensure a good thermal distribution and is used as the major link to the heat pipes on the satellite.


Within the given time frame of the project, technology bricks were developed and a few breadboards were built up. The breadboards were measured and showed nearly full compliance with the given specification. The development was based on standard qualification plans.

Current status


Status date

Thursday, November 8, 2012 - 10:52