Consistent large signal implementation of capacitances driven by two steering voltages for FET modeling

In this paper we discuss the large signal behavior of capacitances extracted using small signal s-parameter measurements. We demonstrate under which conditions charge conservation is not preserved. In many models capacitances depending on two bias voltages are implemented as current sources under large signal conditions. We show an example, where a DC current flows through the mentioned kind of capacitance. Furthermore, we present a simple equivalent circuit solution in order to prevent any DC current to flow through capacitances.