An equivalent circuit for microwave noise at the potential minimum

It has been suggested that an inductive element should be added to Watkins RC equivalent circuit for the microwave noise current fluctuations at the potential minimum of a diode, and that this added element gives closer agreement with more recent work which shows a pronounced peak in noise current near the plasma resonance, . This paper presents an approximate analytical argument for the inclusion of an inductive element, based on the density-function method of analysis, which predicts the proper value for the inductance and yields a curve of reduction factor vs frequency in agreement with more detailed theories. The value of the inductance is such as to resonate with the capacitance of the potential minimum at . A discussion of the linearity of the potential minimum and of the idealized potential-minimum model is also included.