Linear Power Amplifier Research Articles

Система ввода цифровых предыскажений на основе обобщенной полиномиальной модели с памятью для GaN усилителей мощности

Modern power amplifiers based on GaN transistors face a number of problems related to their physical properties and operating conditions. The high output power of such power amplifiers is accompanied by significant nonlinear distortions, especially when operating in saturation mode. Amplifiers based on GaN transistors have pronounced «short» memory effects, which leads to the dependence of current distortions on previous signal states. At the same time, support for broadband signals requires high processing speeds and large computing resources. Classical digital pre-distortion methods do not always cope with the task of effectively compensating for real-time distortion for power amplifiers based on GaN transistors. These problems complicate the process of linearization of power amplifiers based on GaN transistors and require the development of new methods that can effectively compensate for non-linearities and memory effects without significantly increasing the cost and complexity of the system. The purpose of the work is to create and analyze the effectiveness of a digital pre-imaging system based on a generalized polynomial model with memory to improve the linearity and efficiency of power amplifiers based on GaN transistors in wireless communication systems. The paper presents the architecture of the digital preimage input system based on a generalized polynomial model with memory. The use of this model makes it possible to improve the efficiency of suppressing nonlinear distortions at the output of a power amplifier based on GaN transistors. Practical significance – the proposed architecture can be implemented on FPGAs, VLSI or SOC with a minimum amount of computing resources.

Modeling, Design, and Application of Analog Pre-Distortion for the Linearity and Efficiency Enhancement of a K-Band Power Amplifier

Modeling, Design, and Application of Analog Pre-Distortion for the Linearity and Efficiency Enhancement of a K-Band Power Amplifier

A Linear Millimeter-Wave GaN MMIC Doherty Power Amplifier With Improved AM-AM and AM-PM Characteristics

A Linear Millimeter-Wave GaN MMIC Doherty Power Amplifier With Improved AM-AM and AM-PM Characteristics

A parameter design method of LC filter circuit for closed‐loop dynamic power supply system based on linear power amplifier

AbstractThe linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged.

Sparsely Gated Mixture of Experts Neural Network For Linearization of RF Power Amplifiers

Sparsely Gated Mixture of Experts Neural Network For Linearization of RF Power Amplifiers

Recursive Neural Network With Phase-Normalization for Modeling and Linearization of RF Power Amplifiers

Recursive Neural Network With Phase-Normalization for Modeling and Linearization of RF Power Amplifiers

Nonlinear Capacitance Compensation Method for Integrating a Metal–Semiconductor–Metal Varactor with a Gallium Nitride High Electron Mobility Transistor Power Amplifier

A nonlinear capacitance compensation technique is presented in this paper to enhance the linearity of a power amplifier (PA) in the GaN process. The method involves placing an MSM varactor device alongside the GaN HEMT device, which works as the amplifying unit such that the overall capacitance observed at the amplifier input is constant, thus improving linearity. This approach is a reliable and straightforward way to improve PA linearity in the GaN process. The proof-of-concept prototype in this study involves the fabrication of a PA device using a standard GaN HEMT process, which successfully integrates the proposed compensation technique and demonstrates excellent compatibility with existing processes. The prototype has a saturation output power of 18 dBm, a peak power-added efficiency of 51.8%, and a small signal gain of 15.5 dB at 1 GHz. The measured AM–PM distortion at the 5 dB compression point is reduced by more than 50% compared to that of an uncompensated device. Furthermore, the results of third-order intermodulation distortion demonstrate the effectiveness of the linearity enhancement concept, with values improved by more than 5 dB in the linear region compared to those of the uncompensated device. All of the results demonstrate the potential utility of this design approach for wireless communication applications.

Design and optimization of spoof surface plasmon polaritons based multi-octave power amplifier using PSO algorithm

In this article, we explore how spoof surface plasmon polaritons (SSPP) theory can be applied to the design of active radio frequency (RF) power amplifiers (PAs). This work utilizes SSPP structures for the design of both input and output matching networks for a multi-octave PA. In order to perform proper impedance matching, the properties of SSPP unit structures are presented and analyzed. A description of the performance of the initial PA has been provided and discussed. Additionally, particle swarm optimization (PSO) is used to further enhance the performance of the PA circuit. In comparison with an embedded gradient method in a commercial tool, the PSO method results in a better optimization result. The fabricated PA is tested and the results indicate that in the frequency range of 0.5 GHz to 2.9 GHz, it achieves an output power of 40.4 dBm to 41.2 dBm, a power added efficiency of 60.5–65%, and an output gain exceeding 10 dB. Compared to recent work, the multi-octave PA in this work broadens bandwidth while maintaining high output power and PAE. To further verify the linearity of the SSPP-based PA, digital pre-distortion (DPD) is implemented. As a result of the DPD, the linearity of the SSPP PA was greatly enhanced.

Design and Optimization of a Highly Linear Power Amplifier with Novel Active Bias Circuit in InGaP/GaAs HBT MMIC Technology

This paper introduces a highly linear power amplifier (PA) that utilizes a 2-μm InGaP/GaAs hetero-junction bipolar transistor (HBT) process. As communication systems evolve in complexity, the demands for the linearity and static power consumption of HBT power amplifiers are becoming more stringent. Typically, there exists a trade-off relationship between linearity and static power consumption in the design process. Hence, this paper proposes a novel active bias circuit for HBT power amplifiers, along with its layout design. The proposed active bias circuit consists of a differential pair and a current mirror structure, designed to enhance PA linearity while maintaining low quiescent current. Additionally, a novel layout structure is implemented to achieve thermal coupling between the RF transistors and the active bias, further improving PA linearity. As a result of the implementation of the proposed active bias and layout structure, the PA demonstrates high linearity in both amplitude modulation to phase modulation (AM/PM) and amplitude modulation to amplitude modulation (AM/AM) performance, while simultaneously maintaining a low quiescent current. The three-stage PA prototype achieves notable performance metrics, including a peak gain of 32.6 dB at 5.6 GHz, gain flatness of ±0.5 dB from 5.15 GHz to 5.85 GHz, and P1dB of 32.1 dBm at a quiescent emitter current of 180 mA.

Design and Analysis of Complex Neutralization Gain-Boosting Technique With Low-Loss Power Combining for Efficient, Linear D-Band Power Amplifiers

Design and Analysis of Complex Neutralization Gain-Boosting Technique With Low-Loss Power Combining for Efficient, Linear D-Band Power Amplifiers

EFFICIENCY ANALYSIS OF SWITCHING CONVERTER-MODULATOR

The article discusses methods of highly efficient linear RF power amplifier and transmitter design for future 5G/6G networks. Based on a consideration of various known methods for constructing high-efficiency power amplifiers, the prospects of developments using the envelope elimination and restoration (EER, or Kahn method) and envelope tracking (ET) method are substantiated. The prospects for implementing PWM switching converter-modulator for these methods are assessed. Based on the evaluation calculations performed, it is shown that this structure can potentially be used as an EEP/ET modulator for a number of 5G/6G applications and will have advantages over structures using class AB amplification.

A Lightweight Coefficient Update Method for Linearization of Power Amplifiers With Frequent Power Variation

A Lightweight Coefficient Update Method for Linearization of Power Amplifiers With Frequent Power Variation

Augmented Phase-Normalized Recurrent Neural Network for RF Power Amplifier Linearization

Augmented Phase-Normalized Recurrent Neural Network for RF Power Amplifier Linearization

Implementation of Alternating Direction Method of Multipliers for Solving Power Amplifier Linearization Problem: Theoretical Foundations and Proof of Concept

Implementation of Alternating Direction Method of Multipliers for Solving Power Amplifier Linearization Problem: Theoretical Foundations and Proof of Concept

Minimizing Training Signal Length for Power Amplifier Characterization and Linearization

Minimizing Training Signal Length for Power Amplifier Characterization and Linearization

Improved Linearity and Efficiency of 5-GHz HBT Power Amplifier Using Transformer-Based Second Harmonic Trap Network

Improved Linearity and Efficiency of 5-GHz HBT Power Amplifier Using Transformer-Based Second Harmonic Trap Network

Adversarial Modeling Regularization for Modeling and Linearization of Power Amplifiers

Overfitting problem is very common in the coefficient identification process of digital predistortion (DPD) technique. Especially in some related DPD topics, the overfitting problem seriously limits the linearization performance. In this article, to improve the robustness of coefficient identification, we present the adversarial modeling regularization (AMR) technique. By regarding the linear-in-coefficient power amplifier (PA) behavioral models as the prior knowledge of the PA itself, the proposed regularization constrains the PA model’s coefficients by evaluating the fitting performance of other adversarial models. In addition, we present two complexity reduction strategies for the AMR. The AMR is extended and validated under four related tasks that are prone to overfitting: the few-sample learning, the piecewise DPD technique, the aliasing-sampling technique, and the band-limited technique. The experiment results show that the proposed technique can dramatically improve the forward behavioral modeling and linearization performance compared with the other state-of-the-art algorithms in all tasks.

Third-Order Intermodulations Phase Shifting in Power Amplifiers for Spatial Filtering in Multi-Beam 5G mmW Phased Array

This paper proposes an innovative concept of spatial third-order intermodulation products (IMD3) filtering in millimeter-wave 5G phased arrays. This technique aims to relax the linearity constraints on the power amplifiers (PA) and thus power consumption. Implementation of independent control of the phase of IMD3 is proposed by using the nonlinear output capacitance of metal-oxide semi-conductors (MOS) amplifiers under phase-controlled second harmonic injection. The implemented control uses beamforming properties to perform spatial filtering of IMD3 product. A second harmonic injection on a power amplifier is proposed in STMicroelectronics CMOS065SOIMMW technology at 28 GHz. It shows phase control of IMD3 with a range of 35 degrees, allowing relaxation up to 17 dB on the linearity of large phased array power amplifiers.

Phase-Normalized Neural Network for Linearization of RF Power Amplifiers

Phase-Normalized Neural Network for Linearization of RF Power Amplifiers

Attention mechanism based bidirectional LSTM model for broadband power amplifier linearization

AbstractIn this letter, a novel digital predistortion (DPD) model for broadband power amplifier (PA) linearization is proposed, namely Attention Mechanism based Bidirectional Long Short‐term Memory Network (AM‐BiLSTM) model. In order to verify the linearization performance of the AM‐BiLSTM model in digital predistortion process, a 100 MHz bandwidth 5G new radio (5G NR) signal is employed to test a sub‐6G PA operating at 2.6‐GHz. The experimental results show that the adjacent channel power ratio (ACPR) of the PA with AM‐BiLSTM model can be improved by 24 dB which is 6 dB and 3 dB better than the generalized memory polynomial (GMP) model and the Chebyshev polynomials LSTM (CP‐LSTM) model in ref [1], repspectively. Therefore, the proposed AM‐BiLSTM model is very effective for the DPD linearization of broadband PAs.