The stability and passivity of MOSFET device models that use nonreciprocal capacitive elements

An examination is made of the activity and stability of circuits built from device models formed by a linear active or passive multiport resistor in parallel with a positive definite, but nonreciprocal, multiport capacitor. Numerical range methods are used to determine the maximum frequency of oscillation and maximum exponential growth rate of the solutions for both conservation of real power and conservation of complex power. Also examined are the stability and activity of these devices when a positive-definite multiport resistor is added in series. It is shown that with the inclusion of the resistor, the circuit becomes passive at high frequencies even if the capacitor is nonreciprocal. The implications of these results for MOSFET device modeling are discussed