Behavioral Model of RF PAs Including Load Mismatch Effects Based on Canonical Section-wise Piecewise-Linear Function

Abstract

A new, dynamic, double-input, double-output (DIDO), wideband, dynamic, complex envelope, behavioral model for power amplifiers (PAs), accounting for load mismatch effects, is proposed and validated in this paper. The model is constructed based on two-dimensional, dynamic, canonical section-wise piecewise-linear functions (2-D DCSWPL). Compared with existing DIDO behavioral modeling methods, which are almost all exclusively based on polynomial functions, the proposed model permits a vastly extended modeling space for PAs under load mismatch conditions. Experimental examples are given to validate the proposed modeling technique with a 15 W GaN PA under a wide range of output mismatch conditions, driven by a 5 MHz LTE signal. The proposed model shows an average accuracy improvement of 2 dB when compared with the more traditional DIDO memory polynomial (MP) models. In addition, the load reflection-dependent dynamic 2-D CSWPL modeling technique for PAs under mismatch condition is also provided. Compared with load-dependent MP, load-dependent crossover MP (COMP) and load-dependent DIDO MP models, the proposed model shows superior accuracy. Thus, the proposed modeling technique is an excellent choice for the modelling of PA systems that are subject to load mismatch effects. INDEX TERMS Canonical section-wise piecewise-linear Function, dynamic modeling, load mismatch effects, nonlinear behavioral Modeling, RF PAs.

A behavioral model for the linear variable gain amplifier

“…As RF systems become more complex, it is necessary to use behavior-level models instead of circuit-level models for system simulation. Currently, behavioral models are mainly aimed at nonlinear devices, such as power amplifiers [1][2][3] and mixer. 4,5 There are some elements that are always working in linear region, for example, the driver amplifiers and the variable gain amplifiers (VGAs).…”

Mitigation of Load Mismatch Effects Using an Orthogonal Load Modulated Balanced Amplifier

“…For moderate VSWR, typical of mismatched antennas rather than accidental occurrences, the research effort is instead targeting the recovery of performance, or at least the mitigation of the degradation, in terms of output power, efficiency, and linearity. Considering that most PAs for telecom applications require linearization even on the nominal load, many papers have studied ways to make behavioral models [21]- [23] and digital predistorters [24]- [29] load dependent. To recover output power and efficiency, the retuning of the output matching network by controlling some electronically tunable components has been used [30]- [34], including with the use of MEMS [35] and metamaterials [36].…”