A low noise M-type parametric amplifier

A degenerate crossed-field cyclotron wave parametric amplifier in which all three interaction circuits are half-wave coaxial cavities is described. At a signal frequency of 1957 Mc the over-all measured noise figure was 5 db with a contribution due only to beam noise of 3.2 db. The signal saturation gain at low input levels was 40 db. The amplifier operated with a beam current of a few microamperes and a beam voltage of a few tenths of a volt. Several differences between the O-type and the M-type cyclotron wave parametric amplifiers are discussed. Other experimental results are reported.