Investigation of an experimental narrow-band parametric amplifier

A comparison of theory and experiment has been made for a negative-resistance three-frequency parametric amplifier incorporating a single varactor diode, operating in the h.f. band. The effect of diode series loss resistance has been simulated simply by connecting resistors in series with the diode. Good agreement between theory and experiment, in relation to gain, bandwidth and noise figure, has been obtained when the direct current flowing through the diode is negligible. Effects associated with a significant direct current have been investigated.