A Study on Quadratic PHD Models for Large Signal Applications

Pichler, Bernhard; Magerl, Gottfried; Arthaber, Holger

doi:10.1109/tmtt.2019.2915086

Cited by 10 publications

(12 citation statements)

References 12 publications

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“…Previous work has shown that this linear polynomial can be modified to include higher order terms e.g. a quadratic model [12]. Such models allow for larger perturbations at the load while maintaining a reasonable level of accuracy.…”

Section: Theory Of Large-signal Matching Using Behavioural Scattering Wave Modelsmentioning

confidence: 99%

“…Note that for this work i and q will be equal to 2 and k and n equal to 1, therefore the notation of the coefficients can be shortened for simplicity as will be shown later. This is done for the same reasons as in [12], to limit the model the model size and because linear PHD terms allow for sufficient accuracy even when allowing for harmonic mismatch.…”

Section: A Padé Approximation Theory and Extractionmentioning

confidence: 99%

“…Higher order approximations are also possible, e.g. the quadratic PHD (QPHD) model [11], [12]. As the order increases, such polynomial based models can approach global accuracy i.e.…”

Section: Introductionmentioning

confidence: 99%

“…maintain accurate prediction across the full Smith chart under moderate-to-high mismatch conditions. However, higher order polynomials do not extrapolate well, can result in overfitting, and can be difficult to extract [12].…”

Section: Introductionmentioning

confidence: 99%

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Pade-Approximation Based Behavioral Modeling for RF Power Amplifier Design

et al. 2021

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Radio frequency (RF) power amplifier (PA) design using Gallium Nitride (GaN) transistor technology requires accurate device models in order to maximise performance and reduce development time. The current state-of-the-art frequency-domain behavioural models focus on linear and quadratic approximations to the polyharmonic distortion (PHD) formalism. However, the linear approximation suffers from poor accuracy under load mismatch conditions, while the quadratic approximation suffers from poor extrapolation beyond the measured range, leading to erroneous predictions of the optimum load impedances for maximum output power and maximum drain efficiency. In this work, a rational Padé-based approximation is proposed as the model core, and it is shown, through experimental validation, that the Padé approximation-based model can provide superior results in a more scalable format. It can mitigate problems found in the existing PHD models when applied to the matching problem. Specifically, the proposed model produces fewer erroneous solutions for the optimum load points, due to the well-behaved nature of Padé approximants. In addition, for the first time, results are reported on using the behavioural model to determine the optimum impedance for maximum transducer gain in a two-port device model. All results show the Padé model has high potential when compared to the established PHD-derived models in RF PA design.INDEX TERMS Behavioural modelling, Padé approximation, polyharmonic distortion (PHD) modelling, X-parameter model.

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Section: Theory Of Large-signal Matching Using Behavioural Scattering Wave Modelsmentioning

confidence: 99%

Section: A Padé Approximation Theory and Extractionmentioning

confidence: 99%

“…Higher order approximations are also possible, e.g. the quadratic PHD (QPHD) model [11], [12]. As the order increases, such polynomial based models can approach global accuracy i.e.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pade-Approximation Based Behavioral Modeling for RF Power Amplifier Design

et al. 2021

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“…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].…”

Section: Introductionmentioning

confidence: 99%

A simplified active load-pull behavioral model for power amplifiers

Xie

Mao

et al. 2019

IEICE Electron. Express

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To account for load impedance variation, the extraction methods of conventional nonlinear behavioral model require complex and expensive load-pull system. In this letter, a simplified behavioral model for power amplifier (PA) is demonstrated using nonlinear vector network analyzer (NVNA) only for data extraction. An incident signal at fundamental is added in the output of PA as a disturbance signal, and thus load reflection can be realized when its amplitude and phase are swept as active load-pull system does. To increase the robust of the model, a dynamic sweeping method of output incident signal is proposed which proved can cover most of the areas on the fundamental reflection coefficient chart. This method reduces the variables of the nonlinear behavioral model while dramatically simplifies the measurement architecture and reduces the cost of modeling.

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