Simultaneous time domain nonlinear EMS analysis of a LNA complete circuit illuminated by an interfering pulse using 3D-FDTD method

Abstract

This paper proposes a new approach to analyze the susceptibility of a low noise amplifier (LNA) against an electromagnetic pulse in both linear and nonlinear regimes. In this method, simultaneous analysis of the passive parts of the amplifier together with its active part is performed at each time step in a modified finite difference time domain (FDTD) solution to increase the accuracy. First, an EEHEMT based non-linear equivalent circuit model is extracted to represent the transistor. Then, the achieved model is inserted into a three dimensional FDTD solution. Finally, the whole amplifier is analyzed when an electromagnetic pulse impinges the circuit. The proposed method can be used to predict the electromagnetic susceptibility (EMS) of an LNA illuminated by a high power interfering wave that could drive it into the nonlinear regime. The method is applied to a designed and manufactured LNA with the ATF-34143 transistor. Measurements are performed to validate the method in the linear regime. The results show a good agreement between the proposed method and the measurements. Also, the presented method is validated in the non-linear regime by comparing its results with a presented hybrid method.