A Review on Some Aspects of a Gyro-TWT

Abstract

The working principle of a gyro-TWT based on the mechanism of phase synchronism is discussed making a reference to the ω—β diagrams for the beam harmonic and waveguide modes. The input parameters such as the dc magnetic field, beam voltage, location of the beam, beam pitch factor, beam velocity spread, waveguide and beam harmonic mode numbers, etc are identified and their role in controlling the performance of the device is discussed. A simple linear theory is outlined which makes a bridge between the conventional and the gyro-TWTs by way of giving a similar Pierce-type performance formula. The study reveals novel techniques like the tapering and loading of interaction structures for broadband operation, employment of a magnetic cusp followed by a multi-stage depressed collector for efficiency enhancement, etc. The gyro-TWT is also compared with its counterparts like SWCA and CARM.

Indexing terms:

• Travelling-wave tube
• Millimeter-wave/fast wave devices