Theory of nonlinear reactance amplifiers

A class of power amplifiers exists that uses a combination of an ac source and a nonlinear reactance as the basis for amplification. Included in this class are the varactor parametric amplifiers, the so-called dielectric amplifiers, and the magnetic amplifiers. The 3-frequency parametric amplifier is often compared to the maser amplifier since both operate on the 3-frequency principle and both are used for the same application, i.e., low noise front end in microwave receivers. From a circuit point of view, however, they are quite different. The paper develops a theory of a class of amplifiers termed nonlinear reactance amplifiers, and establishes gain-bandwidth limitations by means of Bode's integral constraints and Mason's unilateral gain quantityU.