A low-noise electron-beam parametric amplifier at L-band

This paper describes the development and performance of a low-noise parametric amplifier of the electron-beam type which operates in the vicinity of 1300 mc. This tube is capable of achieving double-channel noise performance equivalent to a residual noise temperature less than 100 degrees Kelvin. At the same time, it provides a unique combination of high stable gain and wide bandwidth not attainable with solid-state parametric amplifiers. The operating principles of the quadrupole amplifier are reviewed briefly as a foundation for an understanding of the performance of this type of amplifier. The development problems encountered at L-band frequencies are discussed along with the solutions reached. A unique solution to the problem of coupling the signals into and out of the tube with minimum loss and over a substantial bandwidth is illustrated. A brief discussion of various applications will point out the advantages and limitations of the quadrupole amplifier in practical systems.