A new complex envelope behavioral model for load mismatched power amplifiers

Abstract

A new dual-input wideband dynamic Quadratic Poly-Harmonic Distortion (D-QPHD) model for unmatched power amplifiers (PAs) is proposed and validated in this article. Compared with the dynamic PHD (D-PHD) model, the new approach significantly improves the prediction accuracy. As the new model has reduced complexity, it is also more robust against possible rank deficiency problems, but still preserves accuracy, when compared with the recently proposed double-input double-output (DIDO) model. The parameters of the new model also have smaller magnitude distribution range compared with the DIDO model, which also improves the model robustness. Hence, it provides a good modeling choice for complex envelope DIDO modeling. K E Y W O R D S behavioral modeling, DIDO model, PHD model, power amplifier, SISO model Int J RF Microw Comput Aided Eng. 2017;27:e21097.

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

“…As seen from the defining equation, the DIDO MP model considers the second excitation signal due to mismatch, x 2 (n) , at port 2, equally important to the first excitation signal,x 1 (n), at port 1. This allows a more general modeling format when compared with the D-PHD model [13] and D-QPHD model [15] (where the D-prefix denotes these as dynamic models). Thus, more information from the second excitation is included in the model, providing the DIDOMP model with a larger area of accurate prediction in the load Smith chart compared with the remaining two models, at the expense of higher model complexity.…”

“…The term a 0 in (15) represents a dc offset, which can be eliminated in this model. If we substitute (15) into 14, we obtainỹ…”

“…As in (15), the termã i,l,0 in (24) represents a dc offset, which can be eliminated in this model. Now, accounting for device memory in (24), and then replacing this modified version of (24) into (23), we obtain the 2D CSWPL based DIDO PA models as…”

“…This model extends the domain of accurate prediction to a larger region of the Smith chart. As a tradeoff between model complexity and prediction accuracy, a second-order approximation of the reflected signal at the output port is proposed [15]. In [16], both dc and RF behavior, with mutual coupling, is captured in the model in order to allow PA efficiency determination.…”

Efficient implementation of a modified‐Volterra radio‐frequency power amplifier nonlinear dynamic model by global rational functions approximation

“…Behavioral modeling of radio‐frequency (RF) and microwave power amplifiers (PAs) for communications has been the focus of considerable research efforts over the last years 1,2,3,4,5,6,7 . Multiple physical and circuital causes concur in determining the complex nonlinear dynamic behavior displayed by RF PAs under typical operating conditions, for example, input/output/interstage matching networks, parasitic supply modulation, charge trapping phenomena, and self‐heating effects, leading to a variety of interlinked memory effects with characteristic time constants distributed across many orders of magnitude.…”