Download or read book Design and Implementation of an Envelope Tracking Power Amplifier Using Switched Amplifiers and Slow Envelopes written by Pedro Pablo Vizarreta Paz and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Envelope Tracking Power Amplifiers for Wireless Communications written by Zhancang Wang and published by Artech House. This book was released on 2014-06-01 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Envelope Amplifier Design for Wireless Base station Power Amplifiers written by Chin Hsia and published by . This book was released on 2010 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Analysis and Design of Envelope Tracking Power Amplifier written by Amir Javan Khoshkholgh and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Envelope Amplifier for Broadband Base station Envelope Tracking Power Amplifier written by Qiuyao Zhu and published by . This book was released on 2011 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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%.

Download or read book High Efficiency Wideband Envelope Tracking Power Amplifier for Next generation Wireless Communications written by Myoungbo Kwak and published by . This book was released on 2011 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book White Space Communication Technologies written by Nuno Borges Carvalho and published by Cambridge University Press. This book was released on 2014-10-09 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to describe RF hardware design for white space applications, including both analog and digital approaches.

Download or read book High Efficiency Linear Envelope Tracking and Envelope Elimination and Restoration Power Amplifier for WLAN OFDM Applications written by Feipeng Wang and published by . This book was released on 2006 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: High efficiency radio frequency (RF) power amplifiers (PAs) are critical in portable battery-operated wireless communication systems because they can dominate the power consumption. Linear power amplifier is required for envelope modulated signal. Traditionally, linear power amplifiers are implemented by "backing-off" the Class-A or Class-AB PA. However for a high peak-to-average (PAR) signal, the average efficiency is much lower than the peak efficiency, which is well down as the inherent trade-off between linearity and efficiency. This dissertation focuses on Envelope Elimination and Restoration (EER) and Envelope Tracking (ET) efficiency enhancement techniques to improve the PA average efficiency for high PAR signal. The EER and ET PA structures are investigated. Wideband ET and "hybrid" EER structures are proposed for WLAN 802.11g signal at 20MHz signal. Two major challenges of the wideband EER and ET PAs are investigated: 1) An adaptive time-alignment algorithm was proposed to calibrate the time-mismatch in wideband EER and ET systems; (2) A high efficiency wideband envelope amplifier is designed for wideband EER and wideband ET applications. A monolithic wideband high efficiency ET power amplifier is designed and implemented for WLAN 802.11g applications in IBM SiGe BiCMOS technology. Digital pre-distortion was implemented to reduce the EVM of the amplifier. The measured overall power-added efficiency of the amplifier is 28% at 20 dBm (100mW) output power.

Download or read book High Efficiency Broadband Envelope Tracking Power Amplifiers written by Jonmei Johana Yan and published by . This book was released on 2013 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to meet the increasing demand for higher data rates while maximizing spectral efficiency, modern wireless communication systems transmit complex non-constant envelope modulation signals with high peak-to-average ratio (PAPR). As a result, conventional power amplifiers must be operated in back-off, leading to a significant efficiency reduction. Various power amplifier architectures (i.e. Doherty, outphasing, and envelope tracking) have been demonstrated to achieve high efficiency for these high PAPR signals. Unlike the other architectures, the envelope tracking power amplifier (ETPA) makes an excellent candidate for multi-band multi-frequency use, while maintaining high efficiency for high PAPR and under average power back-off, as it is fundamentally immune to changes in the frequency of the carrier; it depends only on the envelope of the RF signal. This dissertation focuses on the design of envelope tracking power amplifiers for enabling broadband wireless communication systems. First, a test-bench for evaluating broadband ETPAs is described. A calibration routine, acting as a pre-equalizer, is used to achieve a flat linear response over the entire instantaneous bandwidth of the system, resulting in less than 1% EVM for a 40 MHz LTE signal. Performances of envelope tracking power amplifiers on this test-bench at various frequencies from UHF to millimeter-wave are evaluated, and record efficiencies are demonstrated. Next, this dissertation describes how in under practical usage, the power transmitted fluctuates as a function of the load demands over time. The long-term efficiency of the ETPA is evaluated using Monte-Carlo simulations based on a projected time-varying power profile. Compared to a Doherty PA with the same peak efficiency, the ETPA can provide more than 1.4x reduction in overall energy consumed. The ETPA thus provides significant opportunities for system energy savings under realistic operation. Thirdly, to accommodate the wide range of carrier frequencies required for numerous emerging wireless systems, a multi-octave RFPA based on a compact GaN stacked IC with RC feedback is designed, fabricated, and evaluated. Multi-octave ET operation was demonstrated from 500 to 1750 MHz with >25% efficiency. Compared to its constant drain voltage counterpart, >2x improvement in RFPA efficiency is observed in ET. Lastly, while the ETPA provides advantages such as broad carrier bandwidths and high efficiency under back-off operation, one of the main challenges in ETPA design lies in accommodating wide modulation bandwidths. Adaptive de-troughing, a digital signal processing approach for extending the modulation bandwidth capability of an existing dynamic power supply, is described and evaluated. Measurements demonstrated the ability to extend ET operation to 20 MHz LTE signals. In addition, ~5-6% modulator efficiency enhancement was measured when comparing "standard" to "adaptive" de-troughing supply waveforms.

Download or read book Concurrent Multi band Envelope Tracking Power Amplifiers for Emerging Wireless Communications written by Hassan Sarbishaei and published by . This book was released on 2014 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging wireless communication is shifting toward data-centric broadband services, resulting in employment of sophisticated and spectrum efficient modulation and access techniques. This yields communication signals with large peak-to-average power ratios (PAPR) and stringent linearity requirements. For example, future wireless communication standard, such as long term evolution advanced (LTE-A) require adoption of carrier aggregation techniques to improve their effective modulation bandwidth. The carrier aggregation technique for LTE-A incorporates multiple carriers over a wide frequency range to create a wider bandwidth of up to 100MHz. This will require future power amplifiers (PAs) and transmitters to efficiently amplify concurrent multi-band signals with large PAPR, while maintaining good linearity. Different back-off efficiency enhancement techniques are available, such as envelope tracking (ET) and Doherty. ET has gained a lot of attention recently as it can be applied to both base station and mobile transmitters. Unfortunately, few publications have investigated concurrent multi-band amplification using ET PAs, mainly due to the limited bandwidth of the envelope amplifier. In this thesis, a novel approach to enable concurrent amplification of multi-band signals using a single ET PA will be presented. This thesis begins by studying the sources of nonlinearities in single-band and dual-band PAs. Based on the analysis, a design methodology is proposed to reduce the sources of memory effects in single-band and dual-band PAs from the circuit design stage and improve their linearizability. Using the proposed design methodology, a 45W GaN PA was designed. The PA was linearized using easy to implement, memoryless digital pre-distortion (DPD) with 8 and 28 coefficients when driven with single-band and dual-band signals, respectively. This analysis and design methodology will enable the design of PAs with reduced memory effects, which can be linearized using simple, power efficient linearization techniques, such as lookup table or memoryless polynomial DPD. Note that the power dissipation of the linearization engine becomes crucial as we move toward smaller base station cells, such as femto- and pico-cells, where complicated DPD models cannot be implemented due to their significant power overhead. This analysis is also very important when implementing a multi-band ET PA system, where the sources of memory effects in the PA itself are minimized through the proposed design methodology. Next, the principle of concurrent dual-band ET operation using the low frequency component (LFC) of the envelope of the dual-band signal is presented. The proposed dual-band ET PA modulates the drain voltage of the PA using the LFC of the envelope of the dual-band signal. This will enable concurrent dual-band operation of the ET PA without posing extra bandwidth requirements on the envelope amplifier. A detailed efficiency and linearity analysis of the dual-band ET PA is also presented. Furthermore, a new dual-band DPD model with supply dependency is proposed in this thesis, capable of capturing and compensating for the sources of distortion in the dual-band ET PA. To the best of our knowledge, concurrent dual-band operation of ET PAs using the LFC of the envelope of the dual-band signal is presented for the first time in the literature. The proposed dual-band ET operation is validated using the measurement results of two GaN ET PA prototypes. Lastly, the principle of concurrent dual-band ET operation is extended to multi-band signals using the LFC of the envelope of the multi-band signal. The proposed multi-band ET operation is validated using the measurement results of a tri-band ET PA. To the best of our knowledge, this is the first reported tri-band ET PA in literature. The tri-band ET PA is linearized using a new tri-band DPD model with supply dependency.

Download or read book Envelope tracking Common drain CMOS Power Amplifier with a Switching only Supply Modulator for LTE Applications written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Implementation of a High bandwidth Switching Power Amplifier Using FPGA based Boundary Control written by Zhuang Zhang and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Power amplifiers are critical components for audio, grid simulator and Power Hardware-in-the-Loop (PHIL) applications with the requirement of low cost, high bandwidth and fast dynamics. This thesis proposed an innovative combination of a GaN-based inverter and boundary control implemented in an FPGA to realize a high-bandwidth switching power amplifier with high bandwidth-switching frequency ratios. The control strategy, implementation considerations and the experimental results are presented in this thesis. The influences of the non-ideal factors, including the limited bandwidth of the components and the limited resolution of the analog-to-digital converter when implementing boundary control in a system, have been discussed and analyzed. A proposed compensation method to mitigate the negative impact on the performance of the boundary control from the overall delay has been verified experimentally. This thesis has proposed an analytical method to estimate system bandwidth with boundary control based on the frequency response of the RLC circuit and the specification of the system. Experiment results have verified the proposed method. The Power Amplifier achieves a 30 kHz average switching frequency with the bandwidth of 7.1 kHz, the rated power of 1000 W, amplifier gain of 100 V/V and the power efficiency of 97.78%. The experimental results show that the system can track the step changes of the reference and the load in tens of microseconds.

Download or read book Design of a Power Amplifier and Envelope Amplifier for a Multi band Multi standard Envelope Tracking System written by Yushi Hu and published by . This book was released on 2012 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the design of a Power Amplifier (PA) and envelope amplifier for an Envelope Tracking (ET) system that is aimed at meeting emerging radio standards in terms of power efficiency and linearity. The class J mode of operation, as well as the efficiency and power contours from load pull was exploited to develop an adequate procedure for the design of a broadband and high efficiency radio frequency PA. An in-depth study has also been conducted for a hybrid envelope amplifier topology in order to optimize it for power efficiency through proper setting of its switching stage supply. Two separate proof of concept prototypes of the PA and envelop amplifier were designed, fabricated and tested. The PA designed was able to achieve an average drain efficiency of 73.6%, average output power of 45.89dBm, and an average gain of 18dB between 650MHz and 1.050GHz (48% bandwidth). The envelope amplifier achieved close to 74.6% efficiency for a 5MHz bandwidth LTE signal envelope with 6.4dB peak to average power ratio.

Download or read book The Design of Concurrent Dual Band Envelope Tracking Power Amplifier for Basestations written by Yiqiao Lin and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The linearity and efficiency of a transmitting system is largely determined by its last stage component: the Power Amplifier (PA). In the past century, engineers and scientists have pioneered various architectures to optimize the PA performance - most notably the linearity and efficiency, as these quantities directly correspond to signal integrity and cost, respectively. In this dissertation, the design, implementation, and measurement results of a concurrent dual-band envelope tracking (ET) PA system is detailed. The dual-band PA system incorporates a new envelope tracking (ET) methodology which relaxes the large bandwidth requirement typically placed on supply modulators for dual-band applications, resulting in significant efficiency improvement. Afterwards, the PA linearity optimized through the use of a new, highly stable, and scalable digital predistortion (DPD) scheme, viable for both constant supply as well as modulated supply (ET) dual-band PAs. The developed ET and multi-dimentional DPD system methodologies are then verified using a 10W peak gallium-nitride (GaN) ET PA operating with a dual-band input based on LTE and WCDMA signals, with center frequencies spaced by 310 MHz. The testbed is based on a Altera FPGA Stratix IV and two Analog Device mixed signal DPD boards. The proposed method provides a performance improvement as high as 17 dB in terms of normalized mean square error (NMSE) and 4.6 dB in terms of adjacent channel power ratio (ACPR) in comparison to the conventional dual-band memory polynomial method including ET.

Download or read book Implementation of Envelope Tracking for RF Solid State Amplifiers written by Thomas Leigh Larter and published by . This book was released on 2015 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Envelope Switched Doherty Power Amplifier For RF Applications Preprint written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was developed under a SBIR contract. A new concept of envelope switched Doherty amplifier is introduced. The proposed amplifier maintains maximum efficiency over a wide range of output power fluctuation. The essential idea is to drive two amplifier devices connected in Doherty configuration with a pulsed envelope signal. A high-Q, low loss filter is placed at the output to recover for linearity and to generate a time-varying equivalent load impedance for optimal efficiency performance. Ideally, for a pair of equally sized and identically biased Class B amplifiers, a maximum efficiency, 78.5%, should be maintained all the way down to the 6dB output back-off level. This concept is demonstrated in the experiment with a pair of GaAs FETs at a frequency of 1.87GHz in the PCS band. A maximum output power of 32.7dBm with a PAE of 46% is measured and a PAE of 34.4% is measured at 6dB back-off level including the filter loss at the power amplifier (PA) output. The proposed architecture can be applied in designing high efficiency PAs with non-constant envelope modulations.

Download or read book RF Power Amplifiers for Wireless Communications written by Steve C. Cripps and published by Artech House Publishers. This book was released on 2006-01-01 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.