High-frequency intermodulation analysis of cascode amplifier

By Volterra series analysis using only several device parameters (Cje,β,τ, and rb), the high-frequency nonlinear behavior of cascode amplifiers is analyzed. To verify the validity of this simple analysis, theoretical analysis, simulation, and measurement of intermodulation behavior of cascode amplifier are compared. The results show that simple Volterra series analysis agrees with the simulation and measurement, varying with emitter degeneration inductor and bias current. This simple Volterra series analysis is suitable to estimate the nonlinear characteristics and gives an insight into the conceptual circuit analysis