Impedance-Dependent Wideband Digital Predistortion of Solid-State Radar Amplifiers

Dunn, Zachary; Yeary, Mark; Fulton, Caleb; Rincon, Rafael

doi:10.1109/taes.2017.2691218

Cited by 12 publications

(5 citation statements)

References 29 publications

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“…The nonlinear behavior of the amplifier introduces distortion in the output pulse. Dunn et al used the digital pre-distortion technique to minimize the distortion of amplified signals that appear to be linearly amplified [20][21][22][23]. With the linear assumption on the amplifier in the WPPAR system, this paper focuses on the frequency response of the antenna systems.…”

Section: Theoretical Formulation Of Biasmentioning

confidence: 99%

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Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

Wang

Pang

et al. 2019

Electronics

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The frequency response of wideband polarimetric phased array radar antenna biases polarization measurement. A bias correction method named the iterative frequency division (IFD) algorithm is proposed in this paper to eliminate the effect of frequency response of the antenna system. The method is built on a new measurement bias model in which the effects of frequency response on the backscattering covariance matrix are analyzed. To demonstrate the effectiveness of the proposed method, a wideband microstrip patch array element is designed. Simulation results show that the biases of differential reflectivity ( Z D R ) and linear depolarization ratio ( L D R ) can be decreased to less than 0.1 dB and − 40 dB even for wide beam direction. The proposed method maintains a favorable polarization measurement accuracy for wideband polarimetric phased array radar.

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Section: Theoretical Formulation Of Biasmentioning

confidence: 99%

“…However, the frequency-dependent power amplifier (PA) and antenna system distort the output waveform in the WPPAR [18,19]. To circumvent the problem from PA, some digital pre-distortion schemes have been explored in [20][21][22][23]. Another challenge is from the transmitting/receiving antenna.…”

Section: Introductionmentioning

confidence: 99%

Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

Wang

Pang

et al. 2019

Electronics

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“…• Load-dependent behavioural models, such as in (CAI et al, 2015), (DHAR et al, 2018), (DUNN et al, 2017), in which the model coefficients are parametrized by the complex-valued load reflection coefficient, Γ. In such models, the model coefficients are previously estimated for a batch of Γ values, then are interpolated during the DPD training phase, based on the reflection coefficient that is actually measured at the PA/ antenna interface.…”

Section: Pa Lmm Modelsmentioning

confidence: 99%

“…Alternatively, (DUNN et al, 2017) proposed a load-dependent model that includes a polynomial expression of Γ in the model, as follows:…”

Section: Pa Lmm Modelsmentioning

confidence: 99%

“…Now, we consider the PA LMM DPD models, from the literature, presented in section 2.3. Firstly, the WHFB model is compared to load-dependent behavioural models parametrized by the load reflection coefficient in (CAI et al, 2015), (DHAR et al, 2018), (DUNN et al, 2017. The proposed DPD approach shows the following advantages:…”

Section: Proposed Whfb Dpd Model For Lmm Pamentioning

confidence: 99%

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Digital signal processing techniques for the compensation of analog circuit impairments in impedance mismatched radio-frequency transmitters.

Hemsi¹

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Esta tese investiga e propõe novos modelos para a compensação digital de imperfeições de rádio frequência (RFradio frequency) em transmissores sem fio de banda larga, mais especificamente para amplificadores de potência (PApower amplifiers) não-lineares e sujeitos a descasamento de impedância de carga (LMMload mismatch). Tais imperfeições em transmissores de RF, juntamente com o desbalanceamento entre as componentes em fase e quadratura (IQin-phase and quadrature) em moduladores digitais, são responsáveis por degradar o desempenho do transmissor, tanto em termos de pureza espectral, quanto em qualidade da modulação e taxa de erro de bit (BERbit error rate).Diversos cenários práticos em que PAs estão sujeitos a LMM motivam a pesquisa por modelos comportamentais não-lineares e com memória voltados a predistorção digital (DPDdigital pre-distortion) mais avançados, capazes de superar as limitações relatadas na literatura de modelos tradicionais e que sejam menos complexos do que as abordagens existentes para PA LMM.Nesta tese é proposta a aplicação do modelo polinomial Wiener-Hammerstein com realimentação (WHFB -Wiener-Hammerstein with feedback) como modelo comportamental simplificado para DPD no contexto de PAs sujeitos a LMM.A elevada dimensionalidade da estrutura WHFB proposta pode ser reduzida através de técnicas esparsas de estimação, tais como o operador de encolhimento e seleção absoluto mínimo (LASSOleast absolute shrinkage and selection operator) e extensões de LASSO em blocos, que são capazes de diminuir significativamente o número de coeficientes necessário, reduzindo, assim, o comprimento do filtro de DPD e, proporcionalmente, o custo da filtragem.Além disso, extensões de LASSO voltadas a blocos, como Group-LASSO e Sparse-group LASSO, são aplicadas no contexto de dimensionamento do modelo, ou seja, na tarefa de determinar valores adequados para seus parâmetros, o que, tradicionalmente, requer uma busca exaustiva.Os modelos WHFB denso e esparso são validados experimentalmente através de medições em um set-up de testes experimental e também comparados a outros, incluindo modelos baseados na decomposição em fatores paralelos (PARAFACparallel factors) e na expansão de Laguerre, demonstrando, assim, sua capacidade de compensar adequadamente PAs sujeitos a LMM.Finalmente, é proposta uma nova estratégia de redução do modelo de Volterra, que resulta em um polinômio de memória mais flexível e modular, em que os parâmetros são escolhidos independentemente para cada ordem de não linearidade. Esta abordagem flexível é capaz de descrever com precisão uma gama ampla de condições operacionais/ ambientais de PAs.

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Sparse Estimation Technique for Digital Pre-distortion of Impedance-Mismatched Power Amplifiers

Hemsi

Panazio

2021

Circuits Syst Signal Process

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Impedance-Dependent Wideband Digital Predistortion of Solid-State Radar Amplifiers

Cited by 12 publications

References 29 publications

Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

Digital signal processing techniques for the compensation of analog circuit impairments in impedance mismatched radio-frequency transmitters.

Sparse Estimation Technique for Digital Pre-distortion of Impedance-Mismatched Power Amplifiers

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