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Power Amplifiers

description258 papers
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lightbulbAbout this topic
Power amplifiers are electronic devices that increase the power of a signal, enabling it to drive a load, such as a speaker or antenna. They are essential in communication systems, audio applications, and broadcasting, where they enhance signal strength while maintaining fidelity and minimizing distortion.
lightbulbAbout this topic
Power amplifiers are electronic devices that increase the power of a signal, enabling it to drive a load, such as a speaker or antenna. They are essential in communication systems, audio applications, and broadcasting, where they enhance signal strength while maintaining fidelity and minimizing distortion.

Key research themes

1. How can harmonic and waveform analysis improve the understanding and efficiency of power amplifier operation across power back-off regions?

This research theme focuses on extending classical harmonic and waveform analysis of power amplifiers (PAs) beyond the maximum output power condition, specifically to analyze behavior under power back-off. Considering that modern telecommunication signals exhibit high peak-to-average power ratios (PAPRs), analyzing PA behavior over varying power back-off levels becomes essential for improving efficiency and linearity. Theoretical analyses employ Fourier series expansions and simplified device models assuming constant transconductance and currents with clipping effects to generalize across bias classes (A, B, AB, C, etc.). The insights enable waveform engineering, harmonic shaping, and design optimization to minimize distortion and enhance PA performance.

Key finding: This paper develops an analytical framework using Fourier series to characterize current-mode PAs under different biasing classes and input power levels, extending beyond maximum output power. It introduces parameters to... Read more
Key finding: This study presents a unified analytical model derived via Fourier series that simultaneously characterizes linearity and efficiency of RF power amplifiers considering both strong nonlinearity (current clipping) and weak... Read more
Key finding: This work analyzes the non-idealities in switching power amplifiers related to their output low-pass filtering, which significantly affects signal fidelity and back-off efficiency. It introduces a hysteresis-based PWM... Read more

2. What methods and design strategies optimize the efficiency and output power of broadband power amplifiers across wide frequency bands for advanced communication systems?

This theme examines the methodologies and circuit designs enabling broadband power amplifiers to deliver high output power and efficiency over wide frequency ranges, particularly targeting sub-6 GHz up to millimeter-wave bands for 5G, radar, and satellite communication. Techniques include leveraging device knee-profile modeling for power and efficiency contour prediction, advanced matching network synthesis such as multisection transformers, and integrated power combining using distributed networks. Emphasis is placed on utilizing computational tools (load-pull, source-pull) combined with empirical adjustments to optimize the complex trade-offs between gain, linearity, and efficiency while sustaining broadband operation.

Key finding: The paper proposes a design approach for a sub-6 GHz broadband PA achieving output power levels between 41.5 to 44.3 dBm and power added efficiency (PAE) above 54% across 0.45–3.4 GHz. This method utilizes a simplified... Read more
Key finding: This work demonstrates the design and integration of two gallium nitride (GaN) MMIC PAs operating in the E-band (71-86 GHz), employing ultralow-loss on-chip distributed microstrip power combiners to achieve watt-level output.... Read more
Key finding: This paper introduces a hybrid design methodology combining artificial neural networks (ANN) and optimization algorithms to design class-E power amplifiers tailored for near-field wireless power transfer. Due to the... Read more

3. How can advanced behavioral and piecewise modeling techniques improve the accuracy and efficiency of digital predistortion and linearization of RF power amplifiers with nonlinear amplitude-dependent characteristics?

This research area investigates improved behavioral models for RF power amplifiers with strong amplitude-dependent nonlinear distortion, including those employing advanced architectures like Doherty and load-modulated balanced PAs. Piecewise modeling approaches, including decomposed vector rotation (DVR) and mixture of experts (ME) models, are analyzed for their ability to capture complex nonlinearities and memory effects while providing smooth transitions across subregions of input amplitude. Optimization of model segmentation thresholds and parameters is crucial for computational efficiency and accuracy. The resulting models enable more effective digital predistortion to extend linearity, reduce adjacent channel interference, and maintain efficiency.

Key finding: The paper proposes applying the mixture of experts (ME) framework—a probabilistic piecewise modeling approach with soft partitions—to model RF PAs exhibiting strong amplitude-dependent nonlinearities including memory effects.... Read more
Key finding: This work introduces an iterative optimization algorithm for setting segmentation thresholds in the Decomposed Vector Rotation (DVR) behavioral model used for digital predistortion (DPD). By decomposing the global nonlinear... Read more
Key finding: This paper evaluates the memory-polynomial model—a truncated Volterra series considering diagonal kernel terms—to capture power amplifier memory effects and nonlinearities efficiently. Implemented via MATLAB and Simulink, it... Read more

All papers in Power Amplifiers

A MMIC PA with continuous bias Control circuit for cellular handsets has been implemented. It has been shown that power amplifier with continuous bias control circuit can increase the standby and talk time by lowering the average current... more
The research work presented in this thesis sets out to investigate improvements to the power amplifier (PA) design cycle through the use of Waveform Engineering techniques. This is approached using alternative simulation methods with... more
We present interband cascade light-emitting devices with incoherent and broadband light emission peaked at a wavelength of around 3.7 µm. The substrate-side-emitting devices display higher wall plug efficiencies and maximum output powers... more
We present interband cascade light-emitting devices with incoherent and broadband light emission peaked at a wavelength of around 3.7 µm. The substrate-side-emitting devices display higher wall plug efficiencies and maximum output powers... more
This work presents the design, analysis, and simulation of a single-stage power amplifier integrated with a bandpass filter at 2.4 GHz. The embedded GaAs FET transistor, MGF2407A, in the Advanced Design System tool, is the heart of the... more
Recent advances in printed circuit and packaging technology of microwave and millimeter wave circuits result to the increasing use of MMICs in telecommunication systems. At Microwave and Fiber Optics Lab of NTUA several designs of various... more
A compact parallel coupled line microstrip bandpass filter (BPF) for sub-6 GHz fifth generation (5G) applications is designed operating between edge frequencies of 3.40 and 3.80 GHz. The design is designed and simulated by means of the... more
Engineers designing audio equipment for the high-end audiophile or professional recording markets have a limited selection of high-resolution signal amplifiers that will meet end-user demands for both outstanding objective and critical... more
Wireless electrical energy transfer has many advantages over the same through conducting cab les. This research focusses on developing wireless power transfer circuitusing i nductive coupling. The experiment has b een done b y changing... more
Piece-wise (PW) behavioral models are commonly adopted when modeling RF power amplifiers (PAs) that exhibit strong amplitude dependent nonlinear distortion characteristics. In this paper, we consider a new PW model for PAs based on the... more
Efficient mitigation of power amplifier (PA) nonlinear distortion in multi-user hybrid precoding based broadband mmWave systems is an open research problem. In this article, we carry out detailed signal and distortion modeling in... more
This article investigates digital predistortion (DPD) linearization of hybrid beamforming large-scale antenna transmitters. We propose a novel DPD processing and learning technique for an antenna sub-array, which utilizes a combined... more
Development of Er-doped ultrafast lasers have lagged behind the corresponding developments in Yb-and Tmdoped lasers, in particular, fiber lasers. Various applications benefit from operation at a central wavelength of 1.5 𝜇m and its second... more
Operational behaviors of the class-F and class-F amplifiers are investigated. For the half-sinusoidal voltage waveform of the class-F amplifier, the amplifier should be operated in the highly saturated region, in which the phase relation... more
In this paper, a new method for dynamically estimating and updating the coefficients of a digital predistortion (DPD) linearizer is presented. By means of the partial least squares (PLS) algorithm, the basis matrix used in the DPD... more
This paper presents a new method, based on the adaptive principal component analysis (APCA) technique, that iteratively creates and updates an orthogonal data matrix used to estimate the parameters of power amplifier (PA) behavioral... more
This paper presents a multi lookup table (LUT) implementation scheme for the 3D distributed memory polynomial (3D-DMP) behavioral model used in Digital Predistortion (DPD) linearization for concurrent dual-band envelope tracking (ET)... more
This paper presents a new technique that dynamically estimates and updates the coefficients of a digital predistorter (DPD) for power amplifier (PA) linearization. The proposed technique is dynamic in the sense of estimating, at every... more
This paper presents an estimation/adaptation method based on the adaptive principal component analysis (APCA) technique to guarantee the identification of the minimum necessary parameters of a digital predistorter. The proposed... more
This paper reports a package synthesis method in order to ensure good performances in PAE, output power and bandwidth. The internal matching circuits of the optimized package enable to reach the best impedance pre-matching at fundamental... more
In this paper, we propose a simple polynomial linearisation technique for nonlinear phased arrays including amplitude control. Due to the large number of antennas and thus power amplifiers in the array, it is inefficient to linearise each... more
Since the drain capacitance of the SD57030 is 36.5 pF at 900 MHz, true tran-sient class-E operation is not possible. The class-E configuration is therefore based upon a second-harmonic approximation to class-E operation. A second-harmonic... more
Materi ini membahas dan menganalisis hasil simulasi tentang dioda dan transistor, ditunjang dengan Proteus sebagai bagian komprehensif dari Ujian Tengah Semester mata kuliah Elektronika. Dan tujuan utama artikel ini adalah memberikan... more
El amplificador de potencia es un elemento esencial en cualquier sistema de comunicaciones y es inherentemente no lineal. La no linealidad del amplificador crea recrecimiento espectral, aumentando la emisión de potencia a los canales... more
Recent advances in printed circuit and packaging technology of microwave and millimeter wave circuits result to the increasing use of MMICs in telecommunication systems. At Microwave and Fiber Optics Lab of NTUA several designs of various... more
Radio frequency identification (RFID) is a ubiquitous identification technology nowadays. An on-chip high-performance transmit/receive (T/R) switch is designed and simulated in 0.13-µm CMOS technology for reader-less RFID tag. The switch... more
The two circuit-level parasitic compensation techniques for the Philips metal oxide semiconductor (MOS) model 9 metal oxide semiconductor field effect transistor (MOSFET) at high frequencies (in the GHz range) are presented in this paper.... more
We present the design and implementation of a power combining amplifier that has a bandpass response, providing high rejection to spurious frequencies and intermodulation products that are usually generated in transmission systems. The... more
In order to meet the linearity specification of standards such as GSM EDGE and TETRA the power amplifier (PA) linearisation methods in common usage today result in low DC to RF efficiency (e.g. Cartesian loop and adaptive predistortion).... more
Design of low loss with an enhanced thermal profile power divider/combiner for high power dual-band Radio Frequency (RF) power amplifier applications is given. The practical implementation, low loss and substrate characteristics make this... more
Portable real-time ECG monitor has to resolve many problems related to normal activity and physical exercise as compared to clinical monitors or Normal printing monitors. The most important problems include baseline wandering, muscle... more
In this paper, a new method for dynamically estimating and updating the coefficients of a digital predistortion (DPD) linearizer is presented. By means of the partial least squares (PLS) algorithm, the basis matrix used in the DPD... more
This paper presents a multi lookup table (LUT) implementation scheme for the 3D distributed memory polynomial (3D-DMP) behavioral model used in Digital Predistortion (DPD) linearization for concurrent dual-band envelope tracking (ET)... more
This paper presents an estimation/adaptation method based on the adaptive principal component analysis (APCA) technique to guarantee the identification of the minimum necessary parameters of a digital predistorter. The proposed... more
This paper presents a new technique that dynamically estimates and updates the coefficients of a digital predistorter (DPD) for power amplifier (PA) linearization. The proposed technique is dynamic in the sense of estimating, at every... more
This paper presents a new method, based on the adaptive principal component analysis (APCA) technique, that iteratively creates and updates an orthogonal data matrix used to estimate the parameters of power amplifier (PA) behavioral... more
A modified varactor device using Barium Strontium Titanate (Ba0.6Sr0.4TiO3) thin films for low loss millimeter wave frequency applications is demonstrated in this paper. MIM (Metal Insulator Metal) varactor devices with splits in the... more
While in the process of reviewing Texas Instruments applications notes, including those from Burr-Brown-I uncovered a couple of treasures, this handbook on op amp applications and one on active RC networks. These old publications, from... more
3,860,876 l/1975 Woods ................................ 328/167 3,939,428 2/1976 Shimizu et al. . 3,973,461 8/1976 Johns . 4,000,474 12/1976 Todokoro ............................. 330/35 4,143,245 3/1979 Scholz . 4,180,707 12/1979 Moog.... more
This article reveals the conceptualization and implementation of energy harvesting system that utilize piezoelectric arrays within environments marked by elevated ambient noise levels. The selected methodology involves conducting an... more
This paper presents the design and performance evaluation of a 0.15um GaN Ka-band power amplifier using the Monolithic Microwave Integrated Circuit (MMIC) technique for satellite communication. Low loss prototype network are designed... more
This paper presents a new method, based on the adaptive principal component analysis (APCA) technique, that iteratively creates and updates an orthogonal data matrix used to estimate the parameters of power amplifier (PA) behavioral... more
This paper presents a new technique that dynamically estimates and updates the coefficients of a digital predistorter (DPD) for power amplifier (PA) linearization. The proposed technique is dynamic in the sense of estimating, at every... more
This paper assesses the PAPR for multimode transmitters (WiMAX, WiFi and Bluetooth), considering different combinations of modulations and access techniques (spreading codes and OFDM). Simulations include preamble, header and data fields.... more
In this paper a new filter design concept is proposed and implemented which takes into account the complex loudspeaker impedance. By means of techniques of broadband matching, that has been successfully applied in radio technology, we are... more
Recently, the design of RF power amplifiers (PAs) for modern wireless systems are faced with a difficult tradeoff for example, cellphone; battery lifetime is largely determined by the power efficiency of the PA and high spectral... more
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