Envelope Tracking Power Amplifiers For Wireless Communications
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| Author | : Zhancang Wang |
| Publisher | : Artech House |
| Total Pages | : 363 |
| Release | : 2014-06-01 |
| Genre | : Technology & Engineering |
| ISBN | : 1608077845 |
Envelope tracking technology is seen as the most promising efficiency enhancement technology for RF power amplifiers for 4G and beyond wireless communications. More and more organizations are investing and researching on this topic with huge potential in academic and commercial areas. This is the first book on the market to offer complete introduction, theory, and design considerations on envelope tracking for wireless communications. This resource presents you with a full introduction to the subject and covers underlying theory and practical design considerations.
| Author | : Myoungbo Kwak |
| Publisher | : |
| Total Pages | : 109 |
| Release | : 2011 |
| Genre | : |
| ISBN | : 9781124856230 |
The latest generation of smart devices deployed in cellular networks has created explosive growth in network data traffic, and the increasing demand for broadband services with higher data rates, require higher peak to average power ratio (PAPR) with wider bandwidth. One of the challenges in the conventional power amplifiers (PAs) with fixed supply voltage, is the degraded efficiency and generated heats at a large back-off to meet tight linearity requirements. This dissertation presents high efficiency wideband envelope tracking power amplifiers for 2.1 GHz micro base-stations and 2.5 GHz wireless mobile applications. By superimposing the envelope signal at the drain such that the RF amplifier operates consistently closer to saturation, the overall efficiency is improved and the generated heat is reduced dramatically. In the first part of the dissertation, a high performance BiCMOS DMOS monolithic envelope amplifier for micro-base station power amplifiers is presented. Due to the low breakdown voltage of the CMOS transistors, the high voltage envelope amplifier has been implemented with discrete components with high voltage process. Compared to these discrete solutions, an integrated circuits implementation for the envelope amplifier brings many benefits. The design of monolithic envelope amplifiers for high voltage (VDD = 15 V) envelope tracking applications, and the design techniques to solve the reliability issues with thin gate oxide is described. The overall envelope tracking system employing a GaN-HEMT RF transistor, and fully integrated high voltage envelope amplifier with a 0.35[mu]m BiCMOS DMOS process, is demonstrated. In the second part, a high-efficiency wideband envelope tracking power amplifier for mobile LTE applications will be presented. The CMOS envelope amplifier with hybrid linear and switcher is designed in a 150 nm CMOS process. The envelope amplifier employs direct sensing of the linear stage current to reduce the propagation delay in the switcher. The strategy is demonstrated to improve the efficiency of the complete envelope tracking power amplifier system. The resulting performance of envelope tracking system employing a GaAs HBT-based RF PA with a 5 MHz LTE signal input demonstrated state-of-the-art efficiency while meet the linearity requirement.
| Author | : Earl McCune |
| Publisher | : Cambridge University Press |
| Total Pages | : 495 |
| Release | : 2015-05-21 |
| Genre | : Technology & Engineering |
| ISBN | : 1107059178 |
"Power is dissipated (lost) when this current flows through any resistance, which includes the amplifier's transistor. This dissipated power is the product of the current in the load times the voltage difference between the supply voltage to the amplifier and the output signal voltage. When the voltage supplied to the amplifier is a constant value, and by far the most common design practice, the situation in Fig. 1-2a results. Power dissipation in the amplifier is maximum when the output signal voltage is 1/2 of the supply voltage. When the output signal voltage is higher, even though the current value is larger the voltage drop is less and the power dissipation is lower. Similarly, when the output signal voltage is small, even though the voltage drop is now large the current in the load is smaller and again the power dissipation is lower"--
| Author | : Chin Hsia |
| Publisher | : |
| Total Pages | : 128 |
| Release | : 2010 |
| Genre | : |
| ISBN | : 9781124324258 |
In order to deliver high data rates, modern wireless communication systems transmit complex modulated signals with high peak-to-average ratio, which demands wide bandwidth and stringent linearity performance for power amplifiers. To satisfy spectral mask regulations and achieve adequate error vector magnitude, power amplifiers typically operate at 6 to 10 dB back-off from the maximum output power, leading to low efficiency. To overcome the low efficiency problem, the envelope tracking power amplifier architecture has been proposed for this type of application due to its feature of high efficiency over a wide power range. The overall efficiency of an envelope tracking system relies not only on performance of the RF power amplifier but also on that of an envelope amplifier that provides a dynamically varying power supply voltage. This dissertation focuses on envelope amplifier design for efficiency enhancement of envelope tracking power amplifiers. First, the envelope tracking power amplifier architecture is analyzed, and the efficiency of a RF transistor in the envelope tracking technique is described. Then envelope amplifier behavior is investigated and a general purpose simulator is developed for analyzing and designing an envelope amplifier. Power loss and efficiency of the envelope amplifier is analyzed and compared with experimental results. The design of envelope amplifiers for high voltage (> 30 V) envelope tracking applications is described. A high voltage envelope amplifier is designed, implemented and verified. The overall envelope tracking system employing a GaN-HEMT RF transistor is demonstrated. Finally, a new architecture is developed for the efficiency enhancement of envelope amplifiers, using a digitally assisted controller design. Digital control is utilized to mitigate delay in the control loop inside the envelope amplifier, leading to lower overall power dissipation. A novel envelope amplifier architecture with dual-switcher stages based on the digitally-assisted control strategy is proposed, designed and implemented. The strategy is demonstrated to improve the efficiency of envelope amplifier as well as the system overall efficiency. The resulting performance of envelope tracking system employing a GaAs high voltage HBT with a single carrier W-CDMA input demonstrated state-of-the-art efficiency with good linearity performance.
| Author | : Zhancang Wang |
| Publisher | : Artech House |
| Total Pages | : 389 |
| Release | : 2017-06-30 |
| Genre | : Technology & Engineering |
| ISBN | : 1630814679 |
This cutting-edge resource presents a complete and systematic overview of the practical design considerations of radio frequency (RF) high efficiency load modulation power amplifiers (PA) for modern wireless communications for 4G and beyond. It provides comprehensive insight into all aspects of load modulation PA design and optimization not only covering design approaches specifically for passive and active load modulation operation but also hybrid with dynamic supply modulation and digital signal processing algorithms required for performance enhancement. Passive load impedance tuner design, dynamic load modulation PA, active load modulation PA and Doherty PA design for efficiently enhancement are explained. Readers find practical guidance into load modulation PA design for bandwidth extension, including video bandwidth enhancement techniques, broadband dynamic load amplifiers, topology selection, design procedures, and network output. This book presents the evolution and integration of classical load modulation PA topologies in order to meet new challenges in the field.
| Author | : 鄧厚威 |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2022 |
| Genre | : |
| ISBN | : |
| Author | : Laurent Leyssenne |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 180 |
| Release | : 2011-01-11 |
| Genre | : Technology & Engineering |
| ISBN | : 9400704259 |
Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets is intended to designers and researchers who have to tackle the efficiency/linearity trade-off in modern RF transmitters so as to extend their battery lifetime. High data rate 3G/4G standards feature broad channel bandwidths, high dynamic range and critical envelope variations which generally forces the power amplifier (PA) to operate in a low efficiency “backed-off” regime. Classic efficiency enhancement techniques such as Envelope Elimination and Restoration reveal to be little compliant with handset-dedicated PA implementation due to their channel-bandwidth-limited behavior and their increased die area consumption and/or bill-of-material. The architectural advances that are proposed in this book circumvent these issues since they put the stress on low die-area /low power-consumption control circuitry. The advantages of silicon over III/V technologies are highlighted by several analogue signal processing techniques that can be implemented on-chip with a power amplifier. System-level and transistor-level simulations are combined to illustrate the principles of the proposed power adaptive solutions. Measurement on BICMOS demonstrators allows validating the functionality of dynamic linearity/efficiency management. In Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets, PA designers will find a review of technologies, architectures and theoretical formalisms (Volterra series...) that are traditionally related to PA design. Specific issues that one encounters in power amplifiers (such as thermal / memory effects, stability, VSWR sensitivity...) and the way of overcoming them are also extensively considered throughout this book.
| Author | : Qiuyao Zhu |
| Publisher | : |
| Total Pages | : 125 |
| Release | : 2011 |
| Genre | : |
| ISBN | : 9781124727844 |
Envelope tracking (ET), which is a dynamic supply control technology to realize high efficiency power amplifiers, is a promising approach for base-station transmitters of the future. The envelope amplifier (EA) in ET systems provides a non-constant modulated power supply to the RF transistor. It is challenging to design so that it is both broadband and high efficiency, while meeting the stringent linearity requirements for high peak-to-average ratio signals in modern wireless communication systems. This thesis focuses on EA design and implementation for efficiency enhancement of ET systems with broadband envelope input signals. First, the ET system architecture is analyzed, and the efficiencies of RF transistors and envelope amplifiers are described. Secondly, the principles of the EA operation are investigated, and each circuit stage is carefully designed for broadband signals. Then, an EA model, including the RF transistor load, is developed in PSpice, and many simulations are described in order to better analyze and design the broadband EA for high efficiency. After the design, a broadband EA is implemented on a PCB board. The testing with constant resistive loads is carried out to verify the function and measure the efficiencies of 5 MHz WCDMA and 20 MHz LTE-A downlink envelope signals. Finally, tests on the whole ET system are performed, and the overall drain and power added efficiencies are tabulated. For this broadband envelope amplifier, the efficiency for a 5 MHz WCDMA input signal is above 75%, and for 20 MHz LTE-A, it works robustly with an efficiency of 62%.
| Author | : Steve C. Cripps |
| Publisher | : Artech House Publishers |
| Total Pages | : 456 |
| Release | : 2006-01-01 |
| Genre | : Technology & Engineering |
| ISBN | : 9781596930186 |
This extensively revised edition offers a comprehensive, practical, up-to-date understanding of how to tackle a power amplifier design with confidence and quickly determine the cause of malfunctioning hardware.
| Author | : George D. Vendelin |
| Publisher | : John Wiley & Sons |
| Total Pages | : 1202 |
| Release | : 2021-04-27 |
| Genre | : Technology & Engineering |
| ISBN | : 1118449754 |
Four leaders in the field of microwave circuit design share their newest insights into the latest aspects of the technology The third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques delivers an insightful and complete analysis of microwave circuit design, from their intrinsic and circuit properties to circuit design techniques for maximizing performance in communication and radar systems. This new edition retains what remains relevant from previous editions of this celebrated book and adds brand-new content on CMOS technology, GaN, SiC, frequency range, and feedback power amplifiers in the millimeter range region. The third edition contains over 200 pages of new material. The distinguished engineers, academics, and authors emphasize the commercial applications in telecommunications and cover all aspects of transistor technology. Software tools for design and microwave circuits are included as an accompaniment to the book. In addition to information about small and large-signal amplifier design and power amplifier design, readers will benefit from the book's treatment of a wide variety of topics, like: An in-depth discussion of the foundations of RF and microwave systems, including Maxwell's equations, applications of the technology, analog and digital requirements, and elementary definitions A treatment of lumped and distributed elements, including a discussion of the parasitic effects on lumped elements Descriptions of active devices, including diodes, microwave transistors, heterojunction bipolar transistors, and microwave FET Two-port networks, including S-Parameters from SPICE analysis and the derivation of transducer power gain Perfect for microwave integrated circuit designers, the third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques also has a place on the bookshelves of electrical engineering researchers and graduate students. It's comprehensive take on all aspects of transistors by world-renowned experts in the field places this book at the vanguard of microwave circuit design research.
