Non-linear Model of Negative Impedance Converter for Use in Non-Foster Circuitry

Non-Foster elements are active electronic circuits that behave as hypothetical negative capacitors or negative inductors. Dispersion properties of such elements are the opposite to those of positive capacitors and inductors. Therefore, non-Foster elements may be useful in antenna matching and active metasurfaces. Particularly interesting application is a recently proposed non-Foster antenna-transmitter. Such system may operate in a non-linear regime, which has not been studied thoroughly in the literature. Thus, we propose a non-linear model of a generalized non-Foster element and analyze the influence of non-linearity on its input impedance.