An electron-beam parametric amplifier for the 200 Mc/s region

The paper describes the design and performance of a low-noise electron-beam parametric amplifier of the quadrupole type. This is a transverse-field device in that the electron beam interacts with a radio-frequency field transverse to its direction of motion. Particular attention is directed to the conditions necessary to achieve the lowest overall noise figure of the amplifier. It is shown that these also lead to the broadest amplification bandwidth. The minimum noise figure so far obtained is 1.6 dB at about 200 Mc/s, which corresponds to an amplifier noise temperature of 130° K. This was obtained at an overall gain of 10 dB which required about 2 mW of pump power. The amplification bandwidth was 25 Mc/s. These performance figures compare well with those reported for the original quadrupole amplifier at higher frequencies.