Application of a load-independent Padé model in Power Amplifier design

The ability of a load-independent Padé nonlinear behavioural model to help design the output matching network of a Power Amplifier (PA) is shown for the first time. 50Ω Padé models are extracted at the frequencies of interest, and then the extracted models are used to perform load-pull simulations. The purpose is to find the Smith chart regions for maximum power delivery and drain efficiency in order to obtain the best fundamental load points across the bandwidth. After the load trajectory has been obtained, the Simplified Real Frequency Technique (SRFT) can be used to calculate the load output matching circuit. Measured results are compared with the behavioural simulation results for a PA with output matching only. The measured drain efficiency for the realized amplifier is between 60-70% between 1.6 GHz and 2.4 GHz, providing a 40% bandwidth with a centre frequency of 2.0 GHz. The input matching network of this PA is also realised, and measurement results are given.