Analysis and simulation of spectral regrowth in radio frequency power amplifiers

This work presents a novel method for efficiently analyzing the relationship between spectral regrowth and physical distortion mechanisms in radio frequency power amplifiers. It utilizes a Volterra series model whose coefficients are computed from basic SPICE parameters. The analysis uses a decomposition of the Volterra kernels into simpler subsystems in order to greatly reduce the computation times. The method is applied to the design of several bipolar-transistor power amplifiers after a series-based model is developed for representing the increase in active device forward transit time at high collector current densities. A number of single-stage SiGe power amplifiers have been designed, fabricated, and tested using the IEEE 802.11b and IS-95 modulation schemes at different carrier frequencies, and these results are compared with the theoretical analysis.