Nonlinear Behavioral Modeling Dependent on Load Reflection Coefficient Magnitude

Abstract

A new frequency-domain nonlinear behavioral modeling technique is presented and validated in this paper. This technique extends existing Padé and poly-harmonic distortion models by including the load reflection magnitude, , as a parameter. Although a rigorous approach requires a full 2-D load-pull model to cover the entire Smith chart, simulation and experimental evidence have shown that such a 1-D model-that retains only amplitude information of the load reflection coefficient-can give accuracy close to that of a full 2-D load-pull model. Consequently, neglecting the phase constitutes an approximation that provides large benefits without appearing to lead to a severe compromise in accuracy. Furthermore, compared with traditional load-independent models, the new -dependent models provide a major improvement in model accuracy. After a discussion of the model extraction methodology, examples are provided comparing traditional load-pull -parameter models with the model presented in this paper. The new model not only provides consistently good accuracy, but also has a much smaller model file size. Along with the examples that display the ability of the new modeling technique to predict fundamental frequency behavioral, a second harmonic example is also provided. The modeling approach is also validated using measurements results.

Application of harmonic includedCPL‐QPHDmodel ofGaNdevice for broadbandPAdesign

“…However, the model requires as many impedance conditions as possible, resulting in an excessively large file size for the resulting PHD model. In reference 38, a load‐reflection magnitude‐dependent model has been introduced, that can greatly reduce the model file size; however, interpolation is required for impedance conditions that are not included in the extracted range.…”

A simplified active load-pull behavioral model for power amplifiers

“…On the contrary, behavioral models have been shown much better accuracy and efficiency, and are good for intellectual property (IP) protection, so they have been widely used in recent years [7,8,9]. However, the modeling of behavioral model is usually complicated and require expensive measurement systems, especially for RF power amplifiers [10,11].…”

New Transistor Behavioral Model Formulation Suitable for Doherty PA Design

“…In this model, the core principle is to take advantage of the periodicity of the phase to create a multidimensional Fourier series to approximate a PHD function. Other options such as Padé-approximation-based models [11], [15] and Bayesian inference-based models [16], [17] have been proposed, but all of them need a large number of coefficients or have to internally incorporate an LUT to mimic the load dependence.…”