Extended Saleh model for behavioral modeling of envelope tracking power amplifiers

摘要

In this paper an extended Saleh model is proposed for behavioral modeling of Envelope Tracking Power Amplifiers (ET PAs). The proposed model extends the Saleh model for fixed supply RF PAs by inserting the modulated supply voltage as an additional model variable. Memory effects in both AM/AM and AM/PM characteristics are modeled using respectively a Finite Impulse Response (FIR) filter and a Taylor polynomial with memory. A Least Square Error (LSE) method can be iteratively used for all model coefficient extraction. Simulation data generated in Advanced Design System (ADS) are used to assess the model performance. A downlink LTE signal with 5 MHz of bandwidth is used to run the ET PA simulations in ADS. Model simulations are carried out versus all the swept model nonlinear orders and memory depth to assess the modeling performance trade-offs of the proposed model. NMSE as low as −44.6 dB and ACEPR as low as −53.7 dB were observed as modeling best performance.