Download or read book Multistage Broadband Amplifiers Based on GaNHEMT Technology for 3G 4G Base Station Applications with Extremely High Bandwidth written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN HFETs have been proposed for high power high linearity and high bandwidth applications andreached tremendous output power levels [1]. However, there are relatively few circuit examples especially for wideband power amplifiers fulfilling the requirements of future multiband/multistandard capable 3G/4G base stations. This work presents first promising results of realised GaN based wideband power amplifier demonstrators for the mentionedfield of application. Two different amplifier concepts for thefinal stage of a power amplifier module for medium range multiband base station applications in the L- and S-Bandhave been implemented as first amplifier demonstrators. Theamplifiers have been characterized by using single carrierW-CDMA signals and showed a promising high bandwidthfor output power levels up to> 10 W while meeting the3GPP ACLR specification in a wide frequency range.

Download or read book Push pull Based High Efficiency and High Power Broadband Power Amplifiers for Wireless Base Stations written by Ayman Jundi and published by . This book was released on 2019 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The monthly data throughput by 2021 is forecasted to be ten times that of December 2015. As a result of the on going dramatic increase in demand, service providers are assigned new frequency bands to accommodate more channels to carry more data. However, the usable part of the spectrum is a limited resource so modern communication signals were designed to be more spectrally efficient to send more bits over the same channel bandwidth. However, these spectrally efficient signals have high PAPR. The immediate reaction to these changes was to add additional RF front-end branches to accommodate the new frequency bands. Initially, the PAs used at the time were not optimized for back-off efficiency and where operating at low efficiency which caused significant increase in heat generation for the same average power produced which in turn increased cooling costs and reduced the life time of the PA. After the introduction of back-off efficiency enhancement techniques the PAs became more efficient however they were limited in bandwidth which is typically 10-15%. This work focuses on reducing the redundancy of power amplifiers in communication base stations while maintaining high back-off efficiency. After exploring the literature to understand the limitations of current implementations, it was found that the push-pull topology is often used at low frequency in broadband high power PAs. In the absence of a complimentary transistor pairs the push-pull implantation requires the use of balanced to unbalanced (balun) transformers. Various balun implantations were hence investigated to identify the most suitable option for broadband planar implementation. As a result, a methodology was proposed to co-design the balun and the matching network in order to have better control over the harmonic impedance. An 85 W push-pull PA was then designed based on the proposed methodology with a multi-octave bandwidth as a demonstration of the broadband potential of push-pull PAs at RF frequencies. Next, the two most popular techniques for back-off efficiency enhancement, i.e., ET and load modulation, were studied and the principle of load modulation was found to be more suitable for broadband signal transmission. The Doherty architecture is the most common implementation of load modulation and it comes in two basic variations, the PCL and SCL DPAs. The original architecture concepts are not only band limited but also ill-suited for high frequency designs where the transistors' parasitics introduce significant effect. However, later literature expanded on the original concept of the PCL variation which provided the needed flexibility for wider bandwidth implementations at a higher frequency. Using the broadband implementation and the co-design methodology two push-pull amplifiers were used in a PCL DPA topology and demonstrated that the push-pull utilization doesn't have a significant impact on the bandwidth of the output combiner as an octave bandwidth was achieved with the use of digital Doherty. Lastly, the thesis proposes a new approach for designing high power DPAs with extended bandwidth. It starts with a generic SCL DPA architecture to derive the equations that relate its underlying combiner's ABCD parameters to the transistor's optimum impedance and load impedance. These equations featured the possibility of significantly increasing the load impedance in SCL DPA compared to the one of the popular PCL DPA architecture. This is particularly beneficial when targeting very high power DPAs for macro-cell base stations and broadcast applications where very low load impedance can seriously complicate the design and limit the achievable bandwidth. To further maximize the load impedance increase, the proposed SCL DPA uses a push-pull topology for the main and peaking amplifier stages. A low-loss planar balanced to unbalanced transformer (balun) combiner network is then utilized to realize the SCL DPA combining. The proposed approach was finally applied to design a proof-of-concept 350 W SCL DPA which operates over the band spanning from 720 to 980 MHz. The prototype demonstrated a peak output power of about 55 dBm over a 30% FBW with a 6 dB back-off efficiency, measured using pulsed signal, between 46.6% and 54.6%. Furthermore, the modulated signal based measurement results confirmed the linearizability of the SCL DPA prototype while maintaining a back-off efficiency over 50% for a 7.1 dB peak to average power ratio signal.

Download or read book AlGaN GaN HEMT power amplifiers with optimized power added efficiency for X band applications written by Jutta Kühn and published by KIT Scientific Publishing. This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has arisen out of the strong demand for a superior power-added efficiency (PAE) of AlGaN/GaN high electron mobility transistor (HEMT) high-power amplifiers (HPAs) that are part of any advanced wireless multifunctional RF-system with limited prime energy. Different concepts and approaches on device and design level for PAE improvements are analyzed, e.g. structural and layout changes of the GaN transistor and advanced circuit design techniques for PAE improvements of GaN HEMT HPAs.

Download or read book High Power High Bandwidth GaN MMICs and Hybrid Amplifiers Design and Characterization written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Broadband microstrip and coplanar MMIC amplifiers featuring beyond 10W for X-band radar applications are realized in a AlGaN/GaN HEMT technology on 2" s.i. SiC substrate. Single-stage and dualstage demonstrators with flat gain from 1 GHz to 2.7 GHz and up to 40 W peak power in hybrid microstrip technology for basestation applications are presented. The performance illustrates the potential of this technology with very high bandwidth and superior power density in comparison to GaAs.

Download or read book Microwave High Power High Efficiency GaN Amplifiers for Communication written by Subhash Chandra Bera and published by Springer Nature. This book was released on 2022-11-29 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: The textbook discusses design and analysis of microwave high power and high efficiency amplifiers for communications, appropriate for undergraduate, post-graduate students, practical circuit designers and researchers in the field of electronics and communication engineering. This book covers basics of III-V group semiconductor materials and GaAs and GaN based High Electron Mobility Transistors (HEMTs) most suitable for microwave and mm wave power amplifiers required for present wireless communication systems and upcoming 4G and 5G mobile base stations. The book describes design and analysis of classical class of amplifier operations such as Class-A, B, AB, C and F. The coverage extends to advanced classes of amplifier operation such as extended continuous Class-B/Class-J, and extended continuous Class-F operations for broadband, high power and high efficiency performance. Analytical expressions are derived for circuit elements and performance parameters for clear understanding and required for practical design of power amplifiers. Each topic is supplemented with suitable schematic diagrams, analytical expressions and plotted results for clear understanding.

Download or read book Bandwidth and Efficiency Enhancement in Radio Frequency Power Amplifiers for Wireless Transmitters written by Karun Rawat and published by Springer Nature. This book was released on 2020-03-05 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on broadband power amplifier design for wireless communication. Nonlinear model embedding is described as a powerful tool for designing broadband continuous Class-J and continuous class F power amplifiers. The authors also discuss various techniques for extending bandwidth of load modulation based power amplifiers, such as Doherty power amplifier and Chireix outphasing amplifiers. The book also covers recent trends on digital as well as analog techniques to enhance bandwidth and linearity in wireless transmitters. Presents latest trends in designing broadband power amplifiers; Covers latest techniques for using nonlinear model embedding in designing power amplifiers based on waveform engineering; Describes the latest techniques for extending bandwidth of load modulation based power amplifiers such as Doherty power amplifier and Chireix outphasing amplifiers; Includes coverage of hybrid analog/digital predistortion as wideband solution for wireless transmitters; Discusses recent trends on on-chip power amplifier design with GaN /GaAs MMICs for high frequency applications.

Download or read book Integrated Sub Millimeter Wave High Power Amplifiers in Advanced InGaAs Channel HEMT Technology written by Laurenz John and published by Fraunhofer Verlag. This book was released on 2021-12-09 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by the large absolute bandwidths that are available at the sub-mm-wave frequency range around 300 GHz, wireless high-data-rate communication systems and high-resolution imaging applications are being extensively investigated in recent years. Due to their superior characteristics in terms of noise figure and cutoff frequencies, InGaAs-channel HEMT devices have proven to be a key technology to implement the required active front-end MMICs for these wireless THz systems, enabling ultra-high bandwidths and state-of-the-art noise performance. This work describes the modeling, design, and characterization of 300-GHz HEMT-based power amplifier cells and demonstrates the implementation of highly compact amplifier MMICs and broadband waveguide modules. These amplifiers are key components for the implementation of high-performance chipsets for wireless THz systems, providing high output power for the utilization of next-generation communication and imaging applications. A unique amplifier topology based on multi-finger cascode and common-source devices is developed and evaluated, demonstrating more than 20-mW measured output power at the sub-mm-wave frequency range around 300 GHz.

Download or read book Wideband GaN Microwave Power Amplifiers with Class G Supply Modulation written by Nikolai Wolff and published by Cuvillier Verlag. This book was released on 2019-02-06 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continuous and rapidly growing demand for mobile communication access led to a major increase in the number of base stations worldwide to provide sufficient coverage and quality of service. As a consequence, mobile communication networks have become a significant contributor to global energy consumption. Several advanced topologies for efficiency improvement of RF power amplifiers have been developed. Modulating the amplifier’s supply voltage according to the variation of the envelope signal is one of the most promising concepts. This topology is investigated here, with an architecture that switches the supply voltage of the power amplifier in discrete levels with a class-G supply modulator. The thesis addresses comprehensively all aspects of class-G supply modulation. Several prototype designs were realized to validate the theory and to gain experience on the influence of the corresponding parameters. These include the discrete supply voltage levels, the switching thresholds, and the interface between the RF PA and the class-G supply modulator. Efforts both on improving the RF power amplifiers and developing several class-G supply modulators were also involved. This work covers the progress up to a PA module that provides an instantaneous modulation bandwidth of 120 MHz and achieves better performance than state-of-the art continuous supply modulation systems. Class-G supply modulated RF power amplifiers based on gallium nitride technology exhibit a strong nonlinear behavior, therefore linearization is required. For this purpose, the linearization with digital predistortion based on behavioral models is optimized for the class-G topology and a novel predistorter model is developed and analyzed.

Download or read book Broadband GaN MMIC Power Amplifiers Design written by Maria-Angeles Go and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter makes a brief introduction of the GaN-HEMT technological process development. Based on this technology, it is established a design procedure for broadband high power amplifiers. The design is focused on the synthesis of the matching and stabilization networks of a two-stage amplifier. It is highlighted the need for nonlinear stability analysis to avoid parametric and odd-mode oscillation. Thermal characterization is also critical due to the high power dissipated in high power GaN devices. Finally, we present the analysis of results of two broadband HPA demonstrators.

Download or read book GaN HEMT Low Noise Amplifiers for Radio Base Station Receivers written by and published by . This book was released on 2012 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Highly Efficient Broadband and Linear Power Amplifiers for Base Station Applications for 4G and Beyond written by Konstantinos Mimis and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Efficiency Enhancement of Pico cell Base Station Power Amplifier MMIC in GaN HFET Technology Using the Doherty Technique written by Sashieka Seneviratne and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the growth of smart phones, the demand for more broadband, data centric technologies are being driven higher. As mobile operators worldwide plan and deploy 4th generation (4G) networks such as LTE to support the relentless growth in mobile data demand, the need for strategically positioned pico-sized cellular base stations known as 'pico-cells' are gaining traction. In addition to having to design a transceiver in a much compact footprint, pico-cells must still face the technical challenges presented by the new 4G systems, such as reduced power consumptions and linear amplification of the signals. The RF power amplifier (PA) that amplifies the output signals of 4G pico-cell systems face challenges to minimize size, achieve high average efficiencies and broader bandwidths while maintaining linearity and operating at higher frequencies. 4G standards as LTE use non-constant envelope modulation techniques with high peak to average ratios. Power amplifiers implemented in such applications are forced to operate at a backed off region from saturation. Therefore, in order to reduce power consumption, a design of a high efficiency PA that can maintain the efficiency for a wider range of radio frequency signals is required. The primary focus of this thesis is to enhance the efficiency of a compact RF amplifier suitable for a 4G pico-cell base station. For this aim, an integrated two way Doherty amplifier design in a compact 10mm x 11.5mm monolithic microwave integrated circuit using GaN device technology is presented. Using non-linear GaN HFETs models, the design achieves high effi-ciencies of over 50% at both back-off and peak power regions without compromising on the stringent linearity requirements of 4G LTE standards. This demonstrates a 17% increase in power added efficiency at 6 dB back off from peak power compared to conventional Class AB amplifier performance. Performance optimization techniques to select between high efficiency and high linearity operation are also presented. Overall, this thesis demonstrates the feasibility of an integrated HFET Doherty amplifier for LTE band 7 which entails the frequencies from 2.62-2.69GHz. The realization of the layout and various issues related to the PA design is discussed and attempted to be solved.

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 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 High Linearity and High Efficiency RF MMIC Power Amplifiers in AlGaN GaN HEMT Technology written by Shouxuan Xie and published by . This book was released on 2004 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern wireless communication systems require high performance RF power amplifiers with high linearity and high efficiency. Class B power amplifiers can achieve relatively high efficiency with good bandwidth, and potentially low distortion.

Download or read book 94 GHz High Average Power Broadband Amplifier written by and published by . This book was released on 2003 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: A state-of-the-art gyro-TWT amplifier operating in the low loss TE01 mode has been developed with the objective of producing an average power of 140 kW in the W-Band with a predicted efficiency of 28%, 50dB gain, and 5% bandwidth. The primary objective is to increase the bandwidth of W-band gyrotron amplifiers to several percent by employing a stable high performance gyro-TWT circuit. The amplifier was developed for the extremely important electromagnetic W-Band for future DoD millimeter-wave applications, in particular for the WARLOC radar. Our innovative amplifier has further improved upon the characteristics of the recent NRL-industry high average power W-Band TE01 gyro-klystron and gyro-twstron amplifiers. The bandwidth has been increased by nearly an order of magnitude. The suppression of gyro-BWO oscillation was a critical factor in the design of the TErn gyro-TWT. However, it should be noted that this negative-feedback interaction can be very useful by itself. In particular, a dual mode gyro-BWO has been designed to yield high power in the W-Band over a broad bandwidth, which will provide vital capability for future ECM applications. The two tuning modes of our gyro-BWO are fast tuning by changing the cathode voltage and slow tuning by changing the magnetic field. It will utilize much of the TEO gyroTWT circuit. The tapered device is predicted to generate 10 kW near 94 GHz with over 10% tuning and 20% efficiency.