A genetic algorithm approach to InGaP/GaAs HBT parameter extraction and RF characterization

Abstract

In this paper, a computational intelligence technique is applied to extract and simulate the stationary and high-frequency properties of heterojunction bipolar transistors (HBTs). A set of HBT circuit equations formulated with the Gummel-Poon model in time domain is solved with (1) the waveform relaxation (WR), (2) monotone iterative (MI) method, and (3) genetic algorithm (GA) with floating-point operators. The coupled nonlinear equations are decoupled and solved with the WR and MI methods in time domain, and the results obtained are used for the optimization of the characteristics with the GA method. The iteration can be terminated when the final convergent global solution is obtained. The time domain result is used in analyzing the property of the output third-order intercept point (OIP3) with the fast Fourier transform (FFT). Compared with the SPICE result, our simulation results demonstrate that this method is accurate and stable in high frequency simulation. This approach has practical applications in HBT characterization and radio frequency (RF) circuit optimal design.