Time Modulations to Stabilize Non-Foster Circuits

In this paper, we show how time modulations can be conveniently used to stabilize non-Foster circuits, i.e., circuits whose components violate Foster's reactance theorem. As an example, we study the stabilization of an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L(t)C$</tex> resonator constituted by a time-varying inductance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L(t)$</tex> and a time-invariant negative capacitance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$C &lt; 0$</tex>.