Time-domain stability analysis/design of negative impedance Inverters and converters

Non-Foster circuits are attractive for microwave and antenna applications since they are not restricted by the gain-bandwidth product. Two topologies to implement these components are the Negative impedance converters and Inverters (NIC and NIIs). A problem with these circuits is the potential instability due to the presence of positive feedback. The stability properties of these circuits are discussed with a time-domain technique that computes the Lyapunov exponents for the nonlinear system.