MINIMUM NOISE TEMPERATURE OF DC-PUMPED TRANSVERSE-WAVE ELECTRON BEAM AMPLIFIERS
Abstract
A general analysis is presented of noise in dcpumped amplifiers based on transverse waves. It is shown that any amplifier involving either the cyclotron waves or the synchronous waves has the same minimum noise temperature determined by the conditions at the cathode. The noise temperature can be reduced to an arbitrary small value by increasing the magnetic field at the cathode or by reducing the cathode diameter. It is also shown that the minimum noise temperature is reduced by the smoothing effect of the potential minimum near the cathode. The minimum noise, temperature can be realized by inserting a suitable noise transformer between the cathode and the amplifier. In general, structures with electric or magnetic fields having rotational symmetry such as used in normal electron guns can perform the required transformation. Some specific examples of noise transformers are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 1962
- Accession Number
- AD0285387
Entities
People
- Kjell Blotekjaer
- Tore Wessel-berg
Organizations
- Rome Laboratory