A Two-Port Nonlinear Dynamic Behavioral Model of RF PAs Subject to Wideband Load Modulation

• Published in: IEEE transactions on microwave theory and techniques Vol. 66; no. 2; pp. 831 - 844
• Main Authors: Gibiino, Gian Piero, Lukasik, Konstanty, Barmuta, Pawel, Santarelli, Alberto, Schreurs, Dominique M. M.-P., Filicori, Fabio
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Behavioral modeling; Broadband; Computer simulation; Impedance; large-signal measurements; Load modeling; load modulation; memory effects; Modulation; Nonlinear analysis; Nonlinear dynamical systems; Power amplifiers; power amplifiers (PAs); Predictive models; Radio frequency; Solid modeling
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2017.2759115

This work presents a full two-port, i.e., double input-double output, behavioral modeling approach suitable for radio frequency power amplifiers (PAs) in the presence of dynamic load modulation (DLM). The formulation of the model, based on a first-order approximation of a modified Volterra series, accounts for the nonlinear distortion determined by large-signal operation under mismatched conditions, and also for the memory effects stimulated by a modulated PA input signal, or by the dynamic variations of the PA load. By following an exhaustive procedure defined in the frequency domain, the model of a general purpose commercial PA is extracted over 160 MHz of modulation bandwidth (BW) with nonlinear vector network analyzer measurements. Validation results under 20-MHz BW multisine excitation and injected 80-MHz BW multisine load modulation show improved prediction capabilities with respect to quasi-static or single-input descriptions, allowing for reliable system-level simulations in the presence of DLM.