Design of Non-Foster Negative Capacitances by Using Decomposition of Linvill's Circuit

A simple design approach for non-Foster negative capacitances is presented based on decomposition of a Linvill's negative impedance converter (NIC) circuit. Influence of parameters of the constituent two-port networks on the NIC characteristics is analyzed. Practical design of the non-Foster elements with tolerance suitable for applications in the lower microwave range is shown. As an application example, a stable immittance inverter circuit employing a non-Foster negative capacitance based on realistic bipolar transistor models is demonstrated.