Accurate method for the intermodulation analysis of nonlinear microwave circuits

Accurate prediction of distortion effects is an important point in nonlinear communication systems and device design. As the voltage-controlled current source I_d is the most dominant nonlinearity in a field effect transistor, we present in this paper an efficient method which determines analytically the intermodulation powers from MESFET I/V characteristics. Based on the characteristic surface technique, the procedure consists of first determining the optimum harmonic loads for the nonlinear element and then, using Volterra series representation, to minimize the corresponding intermodulation powers. The validity of the proposed method was confirmed by comparing the computed values with those presented in technical literature