scholarly journals A Weighted Linearization Method for Highly RF-PA Nonlinear Behavior Based on the Compression Region Identification

2021 ◽  
Vol 11 (7) ◽  
pp. 2942
Author(s):  
Jose Alejandro Galaviz-Aguilar ◽  
Cesar Vargas-Rosales ◽  
José Ricardo Cárdenas-Valdez ◽  
Yasmany Martínez-Reyes ◽  
Everardo Inzunza-González ◽  
...  
Keyword(s):  
Power Amplifier ◽  
Nonlinear Behavior ◽  
High Electron Mobility Transistor ◽  
Linearization Method ◽  
Polynomial Model ◽  
High Electron ◽  
Error Vector Magnitude ◽  
Adaptive Modeling ◽  
Highly Nonlinear ◽  
Memory Polynomial

In this paper, we present an adaptive modeling and linearization algorithm using the weighted memory polynomial model (W-MPM) implemented in a chain involving the indirect learning approach (ILA) as a linearization technique. The main aim of this paper is to offer an alternative to correcting the undesirable effect of spectral regrowth based on modeling and linearization stages, where the 1-dB compression point (P1dB) of a nonlinear device caused by memory effects within a short time is considered. The obtained accuracy is tested for a highly nonlinear behavior power amplifier (PA) properly measured using a field-programmable gate array (FPGA) system. The adaptive modeling stage shows, for the two PAs under test, performances with accuracies of −32.72 dB normalized mean square error (NMSE) using the memory polynomial model (MPM) compared with −38.03 dB NMSE using the W-MPM for the (i) 10 W gallium nitride (GaN) high-electron-mobility transistor (HEMT) radio frequency power amplifier (RF-PA) and of −44.34 dB NMSE based on the MPM and −44.90 dB NMSE using the W-MPM for (ii) a ZHL-42W+ at 2000 MHz. The modeling stage and algorithm are suitably implemented in an FPGA testbed. Furthermore, the methodology for measuring the RF-PA under test is discussed. The whole algorithm is able to adapt both stages due to the flexibility of the W-MPM model. The results prove that the W-MPM requires less coefficients compared with a static model. The error vector magnitude (EVM) is estimated for both the static and adaptive schemes, obtaining a considerable reduction in the transmitter chain. The development of an adaptive stage such as the W-MPM is ideal for digital predistortion (DPD) systems where the devices under test vary their electrical characteristics due to use or aging degradation.

scholarly journals Improvement of Small Signal Equivalent Simulations for Power and Efficiency Matching of GaN HEMTs

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 263
Author(s):  
Roberto Quaglia
Keyword(s):  
Power Amplifier ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Large Signal ◽  
Signal Model ◽  
Or Efficiency ◽  
Summary Table ◽  
Matching Networks ◽  
Amplifier Design ◽  
Frequency Power

In high-frequency power-amplifier design, it is common practice to approach the design of reactive matching networks using linear simulators and targeting a reflection loss limit (referenced to the target impedance). It is well known that this is only a first-pass design technique, since output power or efficiency contours do not correspond to mismatch circles. This paper presents a method to improve the accuracy of this approach in the case of matching network design for power amplifiers based on gallium nitride (GaN) technology. Equivalent mismatch circles, which lay within the power or efficiency contours targeted by the design, are analytically obtained thanks to geometrical considerations. A summary table providing the parameters to use for typical contours is provided. The technique is demonstrated on two examples of power-amplifier design on the 6–12 GHz band using the non-linear large-signal model of a GaN High Electron Mobility Transistor (HEMT).

Research on Modeling Methods of Power Amplifier with Memory Effect in Broadband Communication

2014 ◽  
Vol 687-691 ◽  
pp. 4060-4063
Author(s):  
Lu Sun ◽  
Long Long Xue ◽  
Jia Li Wang ◽  
Chun Yang Zhou
Keyword(s):  
Memory Effect ◽  
Power Amplifier ◽  
Polynomial Model ◽  
Behavioral Modeling ◽  
Design System ◽  
Behavioral Models ◽  
Electric Characteristic ◽  
Memory Polynomial ◽  
With Memory ◽  
Frequency Power

Memory effect of power amplifier (PA) due to broadband signals which adopt new modulation technique is becoming obvious, and worsening the linearity of PA. Behavioral modeling for RF (Radio Frequency) power amplifier is indispensable to design digital pre-distortion system by which we can promote the efficiency of PA. According to the simulation data in the software of ADS (Advanced Design System), behavioral models of MRF21085 amplifier can be established by MATLAB. Comparison of memory polynomial model and ADS simulation of MRF21085 amplifier demonstrate memory polynomial model can represent the electric characteristic of it exactly.

scholarly journals Shaping Code in Conjunction with DCT for PAPR Reduction in Multicarrier System

2021 ◽  
Author(s):  
Younes Aimer ◽  
Boubakar Seddik Bouazza ◽  
Smail Bachir ◽  
Claude Duvanaud
Keyword(s):  
Power Amplifier ◽  
Power Efficiency ◽  
Average Power ◽  
Nonlinear Behavior ◽  
Signal Amplitude ◽  
Amplitude Distribution ◽  
Papr Reduction ◽  
Radio Link ◽  
Error Vector Magnitude ◽  
Multicarrier System

Abstract Nonlinear behavior and power efficiency of the Power Amplifier (PA) contradictorily depend on the input signal amplitude distribution. The transmitted signal in multi-carrier modulation exhibits high Peak-to-Average Power Ratio (PAPR) and large bandwidths, leading to the degradation of the radio link and additional generation out-of-band interferences, which degrade the quality of the transmission. Practical solutions exist, like a power back-off, but with unacceptable efficiency performances of the transmitter. This paper deals with efficiency and linearity improvement using a new PAPR reduction method based on the combination of Discrete Cosine Transform (DCT) and shaping technique. The main principle is to determine an optimal coding scheme according to a trade-off between coding complexity and performance benefits in the presence of PA non-linearities. Simulation and experimental results in the context of OFDM signal and using a 20W - 3.7GHz Radio-Frequency Power Amplifier (RF-PA) show an improvement on PAPR reduction of about 3.25dB. Also, the communication criteria like BER (Bit Error Rate) and EVM (Error Vector Magnitude) are improved by about one decade and a half and 8%, respectively.

A Novel PA Behavioral Modeling Using Memory Rational Function

2013 ◽  
Vol 336-338 ◽  
pp. 1602-1607
Author(s):  
Chun Xiao Jian ◽  
Hui Wang ◽  
Gao Sheng Li ◽  
Pei Guo Liu
Keyword(s):  
Rational Function ◽  
Power Amplifier ◽  
Mean Squared Error ◽  
Model Performance ◽  
Behavioral Model ◽  
Polynomial Model ◽  
Function Model ◽  
Nonlinear Characteristics ◽  
Proposed Model ◽  
Memory Polynomial

Aiming at the nonlinear characteristics and memory effects of power amplifier, a memory rational function behavioral model, which based on the memory polynomial model and memoryless rational function model, is proposed. The model coefficients are identified by conjugate gradient method. The estimation of the best model nonlinearity order and the best memory depth is carried out by minimized the normalized mean squared error (MNSE). The model is validated using multi-carrier WCDMA signal and a MRF6S21140H power amplifier by measurement. The result indicates that the proposed model can achieve better model performance with less number of coefficients compared to the memory polynomial model and memoryless rational function model

scholarly journals Frequency Selective Degeneration for 6–18 GHz GaAs pHEMT Broadband Power Amplifier Integrated Circuit

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1588
Author(s):  
Sungjae Oh ◽  
Eunjoo Yoo ◽  
Hansik Oh ◽  
Hyungmo Koo ◽  
Jaekyung Shin ◽  
...  
Keyword(s):  
Frequency Response ◽  
Output Power ◽  
Power Amplifier ◽  
Integrated Circuit ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Matching Networks ◽  
Chip Size ◽  
Parallel Network ◽  
Frequency Selective

In this paper, a frequency selective degeneration technique using a parallel network with a resistor and capacitor is proposed for a 6–18 GHz GaAs pseudomorphic high electron mobility transistor (pHEMT) broadband power amplifier integrated circuit (PAIC). The proposed degeneration network is applied to the source of the transistor to flatten the frequency response of the transistor in conjunction with feedback and resistor biasing circuits. An almost uniform frequency response was achieved at the wide frequency band through optimizing the values of the capacitor and resistor for the degeneration circuit. Single-section matching networks for small chip sizes were adopted for the two-stage amplifier following the flat frequency characteristics of the degenerated transistor. The proposed broadband PAIC for the 6 to 18 GHz band was fabricated using a 0.15 μm GaAs pHEMT process and had a chip size of 1.03 × 0.87 mm2. The PAIC exhibited gain of 15 dB to 17.2 dB, output power of 20.5 dBm to 22.1 dBm, and linear output power of 11.9 dBm to 13.45 dBm, which satisfies the IMD3 of −30 dBc in the 6–18 GHz band. Flatness for the gain and output power was achieved as ±1.1 dB and ±0.8 dB, respectively.

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