Download or read book A Doherty Power Amplifier with Extended Bandwidth and Reconfigurable Back off Level written by Yu-Ting David Wu and published by . This book was released on 2013 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging wireless standards are designed to be spectrally efficient to address the high cost of licensing wireless spectra. Unfortunately, the resulting signals have a high peak-to-average ratio that reduces the base station power amplifier efficiency at the back-off power level. The wasted energy is converted to heat that degrades the device reliability and increases the base-station's carbon footprint and cooling requirements. In addition, these new standards place stringent requirements on the amplifier output power, linearity, efficiency, and bandwidth. To improve the back-off efficiency, a Doherty amplifier, which uses two device in parallel for back-off efficiency enhancement, is deployed in a typical base station. Unfortunately, the conventional Doherty amplifier is narrowband and thus cannot satisfy the bandwidth requirement of the modern base station that needs to support multiple standards and backward compatibility. In this thesis, we begin by studying the class F/F-1 high efficiency mode of operation. To this end, we designed a narrowband, harmonically-tuned 3.3 GHz, 10 W GaN high efficiency amplifier. Next, we investigate how to simultaneously achieve high efficiency and broad bandwidth by harnessing the simplified real frequency technique for the broadband matching network design. A 2 to 3 GHz, 45 W GaN amplifier and a 650 to 1050 MHz, 45 W LDMOS amplifier were designed. Finally, we analyze the conventional Doherty amplifier to determine the cause of its narrow bandwidth. We find that the narrow bandwidth can be attributed to the band-limited quarter-wave transformer as well as the widely adopted traditional design technique. As an original contribution to knowledge, we propose a novel Doherty amplifier configuration with intrinsically broadband characteristics by analyzing the load modulation concept and the conventional Doherty amplifier. The proposed amplifier uses asymmetrical drain voltage biases and symmetrical devices and it does not require a complex mixed-signal setup. To demonstrate the proposed concept in practice, we designed a 700 to 1000 MHz, 90 W GaN broadband Doherty amplifier. Moreover, to show that the proposed concept is applicable to high power designs, we designed a 200 W GaN broadband Doherty amplifier in the same band. In addition, to show that the technique is independent of the device technology, we designed a 700 to 900 MHz, 60 W LDMOS broadband Doherty amplifier. Using digital pre-distortion, the three prototypes were shown to be highly linearizable when driven with wideband 20 MHz LTE and WCDMA modulated signals and achieved excellent back-off efficiency. Lastly, using the insights from the previous analyses, we propose a novel mixed-technology Doherty amplifier with an extended and reconfigurable back-off level as well as an improved power utilization factor. The reconfigurability of the proposed amplifier makes it possible to customize the back-off level to achieve the highest average efficiency for a given modulated signal without redesigning the matching networks. A 790 to 960 MHz, 180 W LDMOS/GaN Doherty amplifier demonstrated the extended bandwidth and reconfigurability of the back-off level. The proposed amplifier addresses the shortcomings of the conventional Doherty amplifier and satisfies the many requirements of a modern base station power amplifier.

Download or read book Doherty Power Amplifiers written by Bumman Kim and published by Academic Press. This book was released on 2018-03-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doherty Power Amplifiers: From Fundamentals to Advanced Design Methods is a great resource for both RF and microwave engineers and graduate students who want to understand and implement the technology into future base station and mobile handset systems. The book introduces the very basic operational principles of the Doherty Amplifier and its non-ideal behaviors. The different transconductance requirements for carrier and peaking amplifiers, reactive element effect, and knee voltage effect are described. In addition, several methods to correct imperfections are introduced, such as uneven input drive, gate bias adaptation, dual input drive and the offset line technique. Advanced design methods of Doherty Amplifiers are also explained, including multistage/multiway Doherty power amplifiers which can enhance the efficiency of the amplification of a highly-modulated signal. Other covered topics include signal tracking operation which increases the dynamic range, highly efficient saturated amplifiers, and broadband amplifiers, amongst other comprehensive, related topics.

Download or read book Extended Bandwidth Doherty Power Amplifier for Carrier Aggregated Signals written by Mehdi Naseri Ali Abadi and published by . This book was released on 2014 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the conventional classes of power amplifiers the efficiency drops at power back-off, whereas in order to maximize the spectral efficiency and data rate, wireless communication standards employ signals with high peak to average power ratio. This results in low average efficiency for power amplifiers, which in turn results in heavy cooling requirements and damage to the environment. To improve the low back-off efficiency Doherty technique has been widely investigated. But, the conventional Doherty power amplifiers are fairly narrowband, while modern transmitters are needed to support multiple standards and operate at multiple frequency bands. This thesis proposes two novel output combiners for Doherty power amplifiers with extended bandwidth. It will be shown analytically how the problem of wideband Doherty can be converted into an impedance synthesization problem. Then two networks to synthesize the desired impedance are proposed. To achieve the proper load modulation over a wide bandwidth, the first proposed combiner employs a quarter-wave short-circuited stub at the output of the peaking transistor and the second proposed combiner uses a parallel LC tank at the same node. In addition to inherent wideband characteristics, the proposed Doherty output combiners have three other important benefits. First, they present small low-frequency impedance for both the main and peaking transistors, which results in improved linearity and linearizability when the amplifier is concurrently driven with multi-band modulated signals. Second, the new combiners result in smaller group delay variation across the band compared to the conventional Doherty amplifier, which results in improved linearizability when the amplifier is driven with extra wideband modulated signals. Finally, the output capacitance of the peaking transistor can be easily absorbed into the combiners without compromising the performance of the amplifier. The thesis starts with an overview of the Doherty power amplifier principles and provides a bandwidth analysis for the conventional Doherty power amplifier. Then it continues with the new approach to extend the bandwidth of Doherty amplifiers with respect to requirements of multi-band transmission. Based on the proposed combiners, two Gallium Nitride 20 W Doherty power amplifiers have been designed and fabricated. The measurement results have been provided to validate the developed theory. The first amplifier covers 1.72 to 2.27 GHz and the second one covers 700 to 950 MHz and both maintain higher than 48 % of drain efficiency at 6 dB back-off across the band. The two amplifiers are successfully linearized when driven with carrier aggregated modulated signals.

Download or read book The Doherty amplifier and beyond written by Luca Piazzon and published by Luca Piazzon. This book was released on 2011-04-11 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: What's a Doherty power amplifier? What's the practical design flow to develop a DPA? May I estimate the achievable performance? May I get more efficiency, gain, back-off and frequencies from my DPA? Whether you have a FAQ or a rare question, inside you'll probably find the answer. This book is a real design manual, which can help the designer to identify, starting from the desired requirements, the best approach to use, simultaneously highlighting the advantages as well as disadvantages that occurs with its adoption.

Download or read book High Efficiency RF and Microwave Solid State Power Amplifiers written by Paolo Colantonio and published by John Wiley & Sons. This book was released on 2009-07-08 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Do you want to know how to design high efficiency RF and microwave solid state power amplifiers? Read this book to learn the main concepts that are fundamental for optimum amplifier design. Practical design techniques are set out, stating the pros and cons for each method presented in this text. In addition to novel theoretical discussion and workable guidelines, you will find helpful running examples and case studies that demonstrate the key issues involved in power amplifier (PA) design flow. Highlights include: Clarification of topics which are often misunderstood and misused, such as bias classes and PA nomenclatures. The consideration of both hybrid and monolithic microwave integrated circuits (MMICs). Discussions of switch-mode and current-mode PA design approaches and an explanation of the differences. Coverage of the linearity issue in PA design at circuit level, with advice on low distortion power stages. Analysis of the hot topic of Doherty amplifier design, plus a description of advanced techniques based on multi-way and multi-stage architecture solutions. High Efficiency RF and Microwave Solid State Power Amplifiers is: an ideal tutorial for MSc and postgraduate students taking courses in microwave electronics and solid state circuit/device design; a useful reference text for practising electronic engineers and researchers in the field of PA design and microwave and RF engineering. With its unique unified vision of solid state amplifiers, you won’t find a more comprehensive publication on the topic.

Download or read book Concurrent Dual band Doherty Power Amplifiers for Carrier Aggregation written by Mingming Liu and published by . This book was released on 2017 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carrier aggregation is the main feature of the Long Term Evolution advanced (LTE-A) standard to increase the spectral efficiency and communication bandwidth. It calls for wireless transmitters to be multi-band and multi-standard to meet the demands of various deployment scenarios. In addition, these transmit radios must efficiently amplify signals characterized with a high peak-to-average power ratio (PAPR), which is caused by advanced modulation schemes. These two factors highlight the need for the multi-band Doherty power amplifier (DPA), which allows the transmitter remain in high efficiency at back-off power levels and maintain that high efficiency over multiple frequency bands. In this work, a novel output combining network is presented for the dual-band DPA design with extended fractional bandwidth for carrier aggregated signals. The proposed output combiner employs a modified Pi-shape network, which enables the absorption of output capacitances from both the main and peaking devices and eliminates the need for phase offset lines which are major sources of bandwidth limitation in the existing multiband DPAs. In addition to performing the impedance inversion, the proposed combiner incorporates the biasing feeds and presents small low-frequency impedances to both the main and peaking transistors. The inclusion of the bias feeds and small low low-frequency impedance feature improves the linearizability of the DPA when stimulated with concurrent dual-band modulated signals. Lastly, by using the gain contour at the back-off power level, the non-linear AM-AM response caused by the varying input capacitance of the main transistor is mitigated. The proposed dual-band output power combiner and the back-off gain contour technique were applied to design of a dual-band two-way Doherty PA using the commercialized 25W Gallium Nitride (GaN) transistor. Measurement of the two-way DPA shows a gain of 7.5- 9.5 dB at 2.05 - 2.3 GHz and 9 - 11 dB at 3.2 - 3.62 GHz. The efficiency at 6 dB back off is greater than 49% and 47% across the two frequency bands. The linearizability of the dual-band DPA is validated using various carrier aggregated signals. The PA exhibits linear behaviour when driven by up to 80 MHz intra-band carrier aggregated signal and 20 MHz concurrent dual-band signal after DPD. Additionally, carrier aggregated signals usually lead to a PAPR value between 8-10 dB. The efficiency of classic two-way DPA deteriorates when dealing with such signals. To cope with the efficiency deterioration, a three-way DPA was designed. Simulations of the three-way DPA show that the gain is greater than 9 dB within the two frequency bands, 2.05 - 2.32 GHz and 3.35 - 3.65 GHz. The efficiency at 10-dB back-off is greater than 40% in the two frequency bands.

Download or read book Extending the Bandwidth of the Doherty Power Amplifier written by David Gustafsson and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Doherty Power Amplifier Efficiency and Bandwidth Enhancement Based on a Generic Design Approach written by Ayman Galal Mohammed Mohammed Barakat and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Doherty Power Amplifier Efficiency and Bandwidth Enhancement Based on a Generic Design Approach written by Ayman Barakat and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research and Design of High Power and High Bandwidth Digital Three Way Doherty Power Amplifier written by Daniel Popp and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Optimization of the Doherty Power Amplifier for Broadband Applications written by Guolin Sun and published by . This book was released on 2012 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of High Efficiency Power Amplifiers for Emerging Wireless Applications written by Jeffery Alan Curtis and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this Ph.D. research, several Ka-Band power amplifiers are designed and built for use in next generation mobile broadband communication systems. The Doherty power amplifier architecture is demonstrated as a possible solution to improving the back-off efficiency of millimeter-wave power amplifiers, since many mobile broadband communication systems employ modulation formats with large peak-to-average power ratios. This research also demonstrates some novel techniques to improve upon the Doherty architecture for millimeter-wave power amplifier design. Two fully integrated Ka-Band Doherty power amplifiers are designed and developed using a 0.15-[mu]m GaAs pseudomorphic high electron mobility transistor (pHEMT) process. The first uses the classic Doherty configuration with some previously developed modifications to resolve some practical issues and achieves a measured small signal gain of 10.3 dB, measured output power at 1-dB compression point (P1dB) of 25.1 dBm, measured peak power added efficiency (PAE) of 38%, and measured PAE of 27% at 6-dB back-off power. The bias network of this same Doherty was then modified by short circuiting some resistors in the gate bias path and it then achieves a measured small signal gain of 10.5 dB, measured output power at 1-dB compression point (P1dB) of 26.9 dBm, measured peak power added efficiency of 42%, and measured PAE of 32% at 6-dB back-off power. The second Doherty amplifier uses a novel load-pull based Doherty technique accounting for nonideal back-off impedance in millimeter-wave power amplifiers and achieves a measured small signal gain of 9 dB, simulated output power at 1-dB compression point (P1dB) of 29 dBm, simulated peak power added efficiency of 46%, and simulated PAE of 35% at 6-dB back-off power. The performance achieved with these power amplifiers makes them a promising candidate for use in next generation mobile broadband communication systems.

Download or read book The Doherty Power Amplifier written by Paolo Colantonio and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Doherty Power Amplifier.

Download or read book Broadband Doherty Power Amplifiers with Enhanced Linearity for Emerging Radio Transmitters written by Hamed Golestaneh and published by . This book was released on 2016 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ever-increasing demand for utilizing wireless spectra has led to development of spectrally efficient radio systems. While these systems offer much higher data throughput, they employ more sophisticated modulation schemes, which result in wideband signals with high peak-to-average power ratios. These signal characteristics significantly complicate the design of RF transmitters, particularly power amplifiers, in terms of power efficiency and linearity requirements. Furthermore, upcoming wireless standards, such as long term evolution advanced (LTE-A) require adoption of carrier aggregation which incorporates multiple component carriers to yield aggregated channels of larger bandwidth (up to 100 MHz). On the other hand, the emerging systems are expected to support legacy standards with minimum area, cost, and power overhead, and thus call for highly-efficient linear broadband power amplifiers capable of efficiently amplifying concurrent modulated signals located over a broad carrier frequency range. This thesis focuses on Doherty power amplifiers (DPAs) with extended high-efficiency range, enhanced bandwidth and improved linearity as a solution for high-efficiency multi-band multi-standard transmitters. It addresses three major concerns associated with DPAs, namely, back-off efficiency, bandwidth, and linearity.

Download or read book Doherty outphasing Power Amplifier Continuum Theory written by Chenyu Liang and published by . This book was released on 2020 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel design theory for dual-input Doherty power amplifiers (PAs) is first presented in this dissertation, in which the auxiliary transistors do not fully turn off at backoff power. Given the input design variables selected by the PA designer, a Doherty load modulation scheme is exactly implemented at the current-source reference planes of the transistors by solving for the characteristic impedance of the Doherty quarter-wave transformer and the resistance of the common load. The Doherty output combiner at the package reference plane that sustains the desired dual-input DPA performance is then synthesized using nonlinear embedding technique and built with a lossless and reciprocal passive circuit. Then an analytic theory for dual-input outphasing power amplifiers that incorporates in one unified treatment the continuum of solutions for power combining including the Doherty and Chireix modes is presented. This unified theory developed at the current source reference planes reveals the performance trade-off achieved by all of the possible PA combiners within the continuum of solutions. Moreover, it identifies novel types of dual-input hybrid Chireix-Doherty (HCD) and hybrid Doherty-max (HDmax) PAs that combine key features of the Doherty and Chireix operations such that the fundamental drain voltages applied to both the main and auxiliary transistors remain constant versus output power levels. As a result, these two hybrid PA modes achieve the maximum flat efficiency response versus power, in contrast to the efficiency drop observed between backoff and peak in a conventional Doherty PA. Finally, a new type of wideband dual-input hybrid Doherty outphasing PA (HDO-PA) is developed in which the load-modulation continuously slides from the HDmax PA mentioned above to the conventional Doherty PA mode as the frequency increases. For a symmetric HDO-PA implementation, this corresponds to the peak-to-backoff fundamental voltage ratio of the auxiliary amplifier linearly varying from 9/7 to 2 with frequency. A transmission-line based wideband HDO-PA prototype is first established at the current source reference planes to cover the frequency band from 1.4-GHz to 2.5-GHz. The wideband HDO-PA is implemented next at the package reference planes by synthesizing the wideband combiner circuit required to sustain the intrinsic load-modulation behavior across the entire bandwidth. This wideband PA design methodology is developed by extending the Doherty-Chireix continuum theory, in such a fashion that the wide band PA performance is achieved by sliding the mode of operation versus the frequency with the Doherty-Chireix continuum.

Download or read book A Novel 3 way Dual band Doherty Power Amplifier written by Ruwaybih Alsulami and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Doherty Power Amplifier with Collector Current and Voltage Controls written by Hien D. Bui and published by . This book was released on 2008 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: