REDUCTION OF NOISE IN CROSSED-FIELD MICROWAVE AMPLIFIERS.
Abstract
The conditions for low-noise operation are established to be the following: (1) the use of a well-focused beam, (2) reduction of the diocotron gain of the gun and drift regions to a minimum possible value, (3) full exploitation of magnetic and space-change smoothing for maximum reduction of noise figure, (4) launching the beam very close to the circuit, (5) reducing the space-charge parameter S close to zero, (6) high power gain, and (7) minimizing the initial beam position fluctuations by reducing the cathode thickness. By combining optimum beam focusing, space-charge smoothing, and beam displacement, low noise figures of 10.5 db for the backward-wave amplifier and 18.4 db for the forward-wave amplifier have been obtained without using noise transducers. A better control of the above factors than was possible with the present experimental tube will result in still lower noise figures. With the noise transducing scheme added to the factors listed above, it should be possible to obtain extremely low noise figures as was done by Wadhwa and Van Duzer. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1966
- Accession Number
- AD0643059
Entities
People
- N. R. Mantena
Organizations
- University of California, Berkeley