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Artigos de revistas sobre o tema "Amplifiers, Radio frequency"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 27 de janeiro de 2023

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1

Mück, Michael, e Robert McDermott. "Radio-frequency amplifiers based on dc SQUIDs". Superconductor Science and Technology 23, n.º 9 (19 de julho de 2010): 093001. http://dx.doi.org/10.1088/0953-2048/23/9/093001.

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2

Sajedin, Maryam, I. T. E. Elfergani, Jonathan Rodriguez, Raed Abd-Alhameed e Monica Fernandez Barciela. "A Survey on RF and Microwave Doherty Power Amplifier for Mobile Handset Applications". Electronics 8, n.º 6 (25 de junho de 2019): 717. http://dx.doi.org/10.3390/electronics8060717.

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This survey addresses the cutting-edge load modulation microwave and radio frequency power amplifiers for next-generation wireless communication standards. The basic operational principle of the Doherty amplifier and its defective behavior that has been originated by transistor characteristics will be presented. Moreover, advance design architectures for enhancing the Doherty power amplifier’s performance in terms of higher efficiency and wider bandwidth characteristics, as well as the compact design techniques of Doherty amplifier that meets the requirements of legacy 5G handset applications, will be discussed.

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3

Togawa, Kazuaki, Hirokazu Maesaka, Reichiro Kobana e Hitoshi Tanaka. "Frequency-segmented power amplification using multi-band radio frequency amplifiers to produce a high-voltage pulse". Review of Scientific Instruments 93, n.º 7 (1 de julho de 2022): 073304. http://dx.doi.org/10.1063/5.0093915.

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A method of frequency-segmented power amplification using multiband radio frequency (RF) amplifiers was proposed to generate stable and arbitrary high-voltage pulses. The concept behind this method is that an arbitrary pulse with a specified duration and sharp edges can be reconstructed using only several frequencies, and most of the power is concentrated on the fundamental frequency. The high-voltage pulse can, therefore, be obtained by amplifying each segmented frequency and then combining it with the RF power combiners. To correct the frequency-dependent group delays and gain of the amplifier circuit and to perform fine-tuning of the pulse structure, a seed pulse is divided into several lines that have bandpass filters, variable delay lines, variable power attenuators, and main RF amplifiers. A prototype pulse amplifier was designed and fabricated based on this method to generate rectangular pulses for the electron beam chopper of an x-ray free-electron laser injector. Flat and stable pulses with a 2 ns width of 0.2 kV height, peak-to-peak flat top of 0.8%, and route-mean-squared peak jitter of less than 0.2% were successively generated in both single- and multi-bunch structures. In the future, this type of pulse generator will play an important role in accelerators that require complicated and precise beam handling at high repetition rates of kHz or MHz.

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4

El Misilmani, H. M., M. Y. Abou-Shahine, Y. Nasser e K. Y. Kabalan. "Recent Advances on Radio-Frequency Design in Cognitive Radio". International Journal of Antennas and Propagation 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/9878475.

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With the growth of mobile data applications, the spectrum allocation is becoming very scarce. To ease congestion and boost speeds, cognitive radio (CR) is currently seen as a major solution and expected to be the key player in the new wireless technologies. In this paper, we will start by introducing the cognitive radio systems, followed by exploring the challenges in designing RF engine, along with an investigation of its antennas, amplifiers, oscillators, and the components that are expected to operate over a wide range of frequencies.

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5

Wiegner, Dirk, Gerhard Luz, Patrick Jüschke, Robin Machinal, Thomas Merk, Ulrich Seyfried, Wolfgang Templ, Andreas Pascht, Rüdiger Quay e Friedbert Van Raay. "AlGaN/GaN-based power amplifiers for mobile radio applications: a review from the system supplier's perspective". International Journal of Microwave and Wireless Technologies 2, n.º 1 (fevereiro de 2010): 95–104. http://dx.doi.org/10.1017/s175907871000022x.

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This paper gives a summarized overview on the progress and achievements on AlGaN/GaN high electron mobility transistors (HEMT)-based power amplifiers (PAs) for mobile radio applications which have been achieved within two national funded German projects during a period of six years. Starting with a first 34 dBm (2.5 W, peak) amplifier in 2003 the impressive progress toward highly efficient S-band mobile radio PAs with up to >50 dBm (100 W) peak output power is described by means of some selected single- and multiband amplifier demonstrators. This progress has been mainly enabled by clear progress on GaN technology, device packaging, and PA design. Targeting at highly efficient single-band amplifier applications, a 2.7 GHz symmetrical Doherty amplifier with up to 45% drain efficiency at close to 45 dBm average output power under single-carrier W-CDMA (Wideband Code Division Multiple Access) operation using digital predistortion can be highlighted. In case of multiband capable amplifiers addressing software-defined radio applications, a class-AB-based demonstrator covering a frequency range from 1.8 to 2.7 GHz was realized. The amplifier showed >30% drain efficiency up to 2.5 GHz as well as up to 40 dBm average output power under single-carrier W-CDMA operation using proprietary digital predistortion. Finally, Alcatel-Lucent's activities on envelope tracking for future efficiency improved GaN-based amplifiers are described.

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6

Fiori, F., e P. S. Crovetti. "Nonlinear effects of radio-frequency interference in operational amplifiers". IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications 49, n.º 3 (março de 2002): 367–72. http://dx.doi.org/10.1109/81.989173.

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7

Magnuski, Mirosław, Maciej Surma e Dariusz Wójcik. "Broadband Input Block of Radio Receiver for Software-Defined Radio Devices". International Journal of Electronics and Telecommunications 60, n.º 3 (28 de outubro de 2014): 233–38. http://dx.doi.org/10.2478/eletel-2014-0029.

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Abstract In the paper a cost-effective input block of the SDR receiver for 0.9 — 2.4 GHz frequency band built of capacitive-tuned selective amplifier and broadband Vivaldi antenna is presented. The applied selective amplifier consists of three identical sections of tunable filters and two stages of monolithic broadband amplifiers. The single filter section proposed by the authors, due to its ability to absorb parasitic inductances of varicap diodes, simplifies usage of encapsulated varicap diodes in design of tunable in broad band selective filters dedicated to input stages of the receivers. Moreover, proposed filter section has small variation of in-band insertion loss in comparison to varicap-tuned filters built of coupled transmission lines which are commonly applied in input blocks of the microwave receivers. The described selective amplifier could be easily integrated on a single substrate with the Vivaldi antenna which is a cost effective way of fabrication of the tunable in broad band input block of a receiver that has desired gain, selectivity and directivity of the antenna.

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8

Watkins, Gavin. "Inductor‐less envelope modulated radio frequency power amplifier using stacked amplifiers and envelope shaping". IET Microwaves, Antennas & Propagation 7, n.º 15 (dezembro de 2013): 1215–20. http://dx.doi.org/10.1049/iet-map.2013.0328.

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9

Mabrok, Mussa, Zahriladha Zakaria e Nasrullah Saifullah. "Design of Wide-band Power Amplifier based on Power Combiner Technique with Low Intermodulation Distortion". International Journal of Electrical and Computer Engineering (IJECE) 8, n.º 5 (1 de outubro de 2018): 3504. http://dx.doi.org/10.11591/ijece.v8i5.pp3504-3511.

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RF power amplifiers are one of challenging blocks in designing radio frequency transceivers, this is due to non-linearity behavior of power amplifiers that leads to inter-modulation distortion. This paper presents the design of wide-band power amplifier which combined with parallel coupled line band pass filter at the input and output of power amplifier to allow the only required frequency band to pass through the power amplifier. Class-A topology and ATF-511P8 transistor are used in this design. Advanced Design System software used as a simulation tool to simulate the designed wide-band power amplifier. The simulation results showed an input return loss (S11) which less than -10dB, and gain (S21) is higher than 10 dB over the entire frequency band and considers as flat as well. The designed amplifier is stable over the bandwidth (K>1). Inter-modulation distortion is -56.919dBc which is less than -50dBc with 10dBm input power. The designed amplifier can be used for the microwave applications which include weather radar, satellite communication, wireless networking, mobile, and TV.

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10

Silveira, Daniel D., Thiago V. N. Coelho e Alexandre Bessa dos Santos. "Evolution of Black-Box Models Based on Volterra Series". Journal of Applied Mathematics 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/638978.

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This paper presents a historical review of the many behavioral models actually used to model radio frequency power amplifiers and a new classification of these behavioral models. It also discusses the evolution of these models, from a single polynomial to multirate Volterra models, presenting equations and estimation methods. New trends in RF power amplifier behavioral modeling are suggested.

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11

Zhou, Shaohua, Cheng Yang e Jian Wang. "Modeling of Key Specifications for RF Amplifiers Using the Extreme Learning Machine". Micromachines 13, n.º 5 (28 de abril de 2022): 693. http://dx.doi.org/10.3390/mi13050693.

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The amplifier is a key component of the radio frequency (RF) front-end, and its specifications directly determine the performance of the system in which it is located. Unfortunately, amplifiers’ specifications degrade with temperature and even lead to system failure. To study how the system failure is affected by the amplifier specification degradation, it is necessary to couple the amplifier specification degradation into the system optimization design. Furthermore, to couple the amplifier specification degradation into the optimal design of the system, it is necessary to model the characteristics of the amplifier specification change with temperature. In this paper, the temperature characteristics of two amplifiers are modeled using an extreme learning machine (ELM), and the results show that the model agrees well with the measurement results and can effectively reduce measurement time and cost.

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12

Muhamed, Mais, Fariz Abboud e Mohamad Alhariri. "Broadband Performance of a 6W Pushpull Power Amplifier on the VHF-UHF Band". International Journal of Electronics, Communications, and Measurement Engineering 11, n.º 1 (janeiro de 2022): 1–8. http://dx.doi.org/10.4018/ijecme.294892.

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In this paper, a broadband 100-700 MHz power amplifier was designed. The results of simulation are compared with the measurements,The shunt feedback of power amplifier module provides the linear and broadband frequency amplification. The push-pull topology with ferrite balun provides enhanced efficiency and high power generation along In this work a commercially available LDMOS transistor (D2003UK) is used, The amplifier can deliver 6W to a 50 ohm load and has 14dB gain.Broadband high power amplifiers are considered as key components in next generation software defined radio communication systems. In principle, application of a linear, highly efficient wide band amplifier can replace several narrow band power amplifiers, yielding reduced costs and form factor, This paper uses D2003UK a transistor to achieve a 6 Watt amplifier for broad band .

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13

Jebali, C., N. Boulejfen, M. Rawat, A. Gharsallah e F. M. Ghannouchi. "Modeling of wideband radio frequency power amplifiers using Zernike polynomials". International Journal of RF and Microwave Computer-Aided Engineering 22, n.º 3 (23 de fevereiro de 2012): 289–96. http://dx.doi.org/10.1002/mmce.20575.

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14

Wang, Z., Q. Y. Tan, Y. R. Lu, S. L. Gao, Y. Xia, S. Liu, M. Y. Han e J. Zhao. "Design and cold measurements of a coupled RFQ-SFRFQ cavity". Journal of Instrumentation 17, n.º 02 (1 de fevereiro de 2022): T02008. http://dx.doi.org/10.1088/1748-0221/17/02/t02008.

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Abstract Based on the previous research on 26 MHz coupled RFQ-SFRFQ (Radio Frequency Quadrupole-Separated-function Radio Frequency Quadrupole) cavity, we propose a higher frequency coupled RFQ-SFRFQ structure to accelerate proton beam from 35 keV to 2.5 MeV in continuous wave (CW) mode. RFQ and SFRFQ are placed in a single cavity, which greatly reduces the size of the accelerator. Instead of two RF amplifiers, only one RF amplifier is needed with this structure, as a result, this structure becomes more compact. The beam dynamic design and electromagnetic simulation have been accomplished. A 104 MHz coupled RFQ-SFRFQ aluminum model cavity has been constructed and tested at low power successfully, and the results show good agreement with the simulations.

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15

Hasegawa, Naoki, e Naoki Shinohara. "Sidelobe reduction with a GaN active array antenna". Wireless Power Transfer 4, n.º 2 (setembro de 2017): 113–19. http://dx.doi.org/10.1017/wpt.2017.8.

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This work proposes a tunable sidelobe reduction method based on a GaN active-antenna technique, in which the output radio frequency power is controlled by the DC drain voltage of the amplifiers. In this study, a 1 × 4 array of active antenna with GaN amplifiers is designed and fabricated. GaN amplifiers capable of up to 10 W-class power output are fabricated and arranged for a four-way active-array antenna. The fabricated single-stage GaN amplifier offers a maximum power-added efficiency of 59.6% and a maximum output power of 39.3 dBm. The maximum output power is decreased to 36.5 dBm upon decreasing the operating drain voltage from 55 to 35 V. In this study, a 4.5 dB sidelobe reduction is demonstrated in a 1 × 4 active antenna based on this output power difference for each amplifier.

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16

Kim, Bruce C., Sai Evana e Rahim Kasim. "Packaging of MEMS for Integrated RF Circuit Verifications". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, DPC (1 de janeiro de 2011): 000926–51. http://dx.doi.org/10.4071/2011dpc-tp24.

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This paper provides development of MEMS switches and packaging of MEMS to test radio frequency circuits used in wireless products such as cell phones and network routers. We discuss fabrication of MEMS using low voltage magnetic materials and their configurations to achieve the optimum switch to test RF low noise amplifiers. We have accomplished a very unique methodology to test low noise amplifiers using built-in sellf-test technique and our MEMS switches are proposed to achieve the verification of low noise amplifiers. Furthermore, we have used MEMS switches that we developed to perform self calibration to correct for the parametric variations and faults within the deep submicron CMOS circuits. We also discuss packaging of MEMS and low noise amplifier using 3D TSV technology.

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17

Tomov, M. B., P. G. Kogias, S. M. Sadinov e M. N. Malamatoudis. "Comparative criteria for objective evaluation of the efficiency of RF power amplifiers". Journal of Physics: Conference Series 2339, n.º 1 (1 de setembro de 2022): 012031. http://dx.doi.org/10.1088/1742-6596/2339/1/012031.

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Abstract Objective comparison of radio frequency amplifiers, which are infinitely diverse in their parameters and purpose is a difficult engineering task. For its successful solution it is necessary to define objective criteria that allow to quantify qualitatively and quantitatively the scheme and mode of operation of the amplifier, without this assessment depending on the absolute values of current, voltage, power and parameters of active and passive elements in the electronic circuit.

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18

Agarwal, Nitin, Manish Gupta e Manish Kumar. "AN EXTENSIVE REVIEW ON: LOW NOISE AMPLIFIER FOR MILLIMETER AND RADIO FREQUENCY WAVES". Jurnal Teknologi 84, n.º 1 (27 de novembro de 2021): 231–39. http://dx.doi.org/10.11113/jurnalteknologi.v84.16524.

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In today’s world, radio receiver system is a prevailing wireless technology in that the major part is Low Noise Amplifier (LNA) which widely used to improve weak signals in many applications with millimeter and radio frequency waves such as optical communication, multimode transceivers and measurement instrumentations. The real drawbacks of LNA is that it fails to maintain specific properties in critical conditions like as minimum power consumption, provide low noise figure, input matching and linearity. Additionally, promoted by various application demands, design methods and control methods must require to improve performance of LNA. The performance of LNA can be improved by adding extra components in basic circuit by proper arrangement for millimeter and radio frequency waves. The review paper provides information about design methodology, optimization techniques and control techniques. The different design of LNA is reviewed and analyzed such as 3-stage near-mm Wave LNA, 5-stage near-mm Wave LNA, common-gate amplifier, shunt-feedback amplifier, Resistor-terminated common-source amplifier, Traditional inductor-less amplifiers, cascode connection and double common source. This review paper also provides the information about design circuit diagram. The performance improvement of LNA can be achieved with the help of different techniques and our review based on optimization and control techniques with parameter tuning. Finally, the direction for the future study is presented based on review analysis of LNA.

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19

Liu, Leisong, Yuantian Lu, Xin Zhuang, Qunying Zhang e Guangyou Fang. "Noise Analysis in Pre-Amplifier Circuits Associated to Highly Sensitive Optically-Pumped Magnetometers for Geomagnetic Applications". Applied Sciences 10, n.º 20 (15 de outubro de 2020): 7172. http://dx.doi.org/10.3390/app10207172.

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This paper analyzes the noise sources in photoelectric detection circuits with several low-noise operational amplifiers cores. The fabricated circuits are low-noise pre-amplifiers that are used for optically pumped magnetometers. In the proposed circuits, the noise levels of equivalent output voltage are calculated, and the results are in accordance with measurements. With a cooperation of several operational amplifiers, we select LT1028 from linear technologies as the core for our detection circuit, which has an output signal-to-noise ratio of more than 2 × 105 up to the frequency of 100 kHz. By analyzing the individual noise sources in the detection circuit, the dominant noise source is confirmed as the photocurrent shot noise below 200 kHz. Beyond this frequency, the voltage noise source in the operational amplifier dominates. Besides, the lamp power, the radio frequency (RF) power, the temperature variations, and their influences on the sensitivity are studied and optimized. Finally, an optically pumped magnetometer with cesium head is established, showing an intrinsic sensitivity of 85 fT/√Hz. This sensitivity is realized under a geomagnetic magnetic field strength of 53 μT.

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20

Gurov, E. V., S. U. Uvaysov, V. V. Chernoverskaya e R. M. Uvaysov. "Very high frequency radio receiver preselector design". Russian Technological Journal 9, n.º 6 (2 de dezembro de 2021): 37–45. http://dx.doi.org/10.32362/2500-316x-2021-9-6-37-45.

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Objectives. The quality of a radio receiver preselector largely determines its main characteristics, including sensitivity. A preselector usually consists of linear elements: inductors, capacitors, low noise amplifiers, and switches. At high frequencies, the components cannot be considered as ideal ones, since active and reactive parasitic parameters significantly affect the frequency response of the components and, as a consequence, the network. Therefore, simulation of the networks requires more sophisticated component models, which take into account parasitic parameters. However, if refined components models are applied, it is still possible to obtain unsatisfactory results, since interconnections and footprints pads also affect the frequency response. This is true even if short lines with a length of about 5 mm are used at frequencies of about 100 MHz. These features must be taken into account for RF network design. The purpose of the work is to ensure the required characteristics of the preselector in the design process based on computer simulation.Methods. Egor Gurov’s methodology for analog VHF LC-filters was applied to radio receiver preselector design. The methodology contains the methods of discrete optimization, Monte-Carlo method, momentum analysis with Green’s functions. Experimental results were obtained by prototype implementation and measurement with a vector network analyzer. The purpose of the work is to ensure the required preselector characteristics in the design process based on computer simulation.Results. The article presents the preselector design process. The preselector contains two analog switches, an analog band-pass filter, an analog high-pass filter, and a low-noise amplifier. Simulation and experimental results with their comparison are presented in the article.Conclusions. Satisfactory results were obtained. It means that Egor Gurov’s method can be applied for more complex networks design such as radio receiver preselectors.

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21

del Pino, J., Sunil L. Khemchandani, D. Galante-Sempere e C. Luján-Martínez. "A Compact Size Wideband RF-VGA Based on Second Generation Controlled Current Conveyors". Electronics 9, n.º 10 (30 de setembro de 2020): 1600. http://dx.doi.org/10.3390/electronics9101600.

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This paper presents a methodology to design a wideband radio frequency variable gain amplifier (RF-VGA) in a low-cost SiGe BiCMOS 0.35 μm process. The circuit uses two Class A amplifiers based on second-generation controlled current conveyors (CCCII). The main feature of this circuit is the wideband input match along with a reduced NF (5.5–9.6 dB) and, to the authors’ knowledge, the lowest die footprint reported (62 × 44 μm2 area). The implementation of the RF-VGA based on CCCII allows a wideband input match without the need of passive elements. Due to the nature of the circuit, when the gain is increased, the power consumption is reduced. The architecture is suitable for designing wideband, low-power, and low-noise amplifiers. The proposed design achieves a tunable gain of 6.7–18 dB and a power consumption of 1.7 mA with a ±1.5 V DC supply. At maximum gain, the proposed RF-VGA covers from DC up to 1 GHz and can find application in software design radios (SDRs), the low frequency medical implant communication system (MICS) or industrial, scientific, and medical (ISM) bands.

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22

Baytekin, B., e R. G. Meyer. "Analysis and simulation of spectral regrowth in radio frequency power amplifiers". IEEE Journal of Solid-State Circuits 40, n.º 2 (fevereiro de 2005): 370–81. http://dx.doi.org/10.1109/jssc.2004.840968.

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23

Rönnow, D., e M. Isaksson. "Digital predistortion of radio frequency power amplifiers using Kautz-Volterra model". Electronics Letters 42, n.º 13 (2006): 780. http://dx.doi.org/10.1049/el:20060460.

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24

Hassan Abdelhafiz, Abubaker, Oualid Hammi, Azzedine Zerguine e Fadhel M. Ghannouchi. "Lattice-based memory polynomial predistorter for wideband radio frequency power amplifiers". IET Communications 8, n.º 17 (27 de novembro de 2014): 3122–27. http://dx.doi.org/10.1049/iet-com.2014.0129.

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25

Sharma, Deepak Kumar, Akhilesh Jain, Kriti Pathak e Mahendra Lad. "Compact dual-channel radio frequency power sensor for solid state amplifiers". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 944 (novembro de 2019): 162559. http://dx.doi.org/10.1016/j.nima.2019.162559.

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Bachir, S., e C. Duvanaud. "Linearization of radio frequency amplifiers using nonlinear Internal Model Control method". AEU - International Journal of Electronics and Communications 65, n.º 6 (junho de 2011): 495–501. http://dx.doi.org/10.1016/j.aeue.2010.07.004.

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27

Abuelma'atti, M. T. "Radio frequency interference by demodulation mechanisms present in bipolar operational amplifiers". IEEE Transactions on Electromagnetic Compatibility 37, n.º 2 (maio de 1995): 306–10. http://dx.doi.org/10.1109/15.385901.

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28

Hamadou, Aissatou. "Implementation of direct current to direct current converter exploiting power amplifier". Annals of Electrical and Electronic Engineering 3, n.º 3 (março de 2020): 1–7. http://dx.doi.org/10.21833/aeee.2020.02.002.

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In the last years, RF power amplifiers are taking advantage of the switched dc-dc converters to use them in several architectures that may improve the efficiency of the amplifier, keeping good linearity. In this study a DC-DC power converter design suitable for high-frequency applications by using a class E power amplifier (Inverter), instead of using small battery values choosing Radio Frequency (RF) values and getting high efficiency of output voltage and a maximum of current and voltage values between 0-9 mW of power input in rectifier, the class E power amplifier designed by using GaN HEMT device and the power added efficiency of 64% after getting optimization of matching network and the gain is 14.4 dBm.

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Hamadou, Aissatou. "Implementation of direct current to direct current converter exploiting power amplifier". Annals of Electrical and Electronic Engineering 3, n.º 3 (março de 2020): 1–7. http://dx.doi.org/10.21833/aeee.2020.03.001.

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In the last years, RF power amplifiers are taking advantage of the switched dc-dc converters to use them in several architectures that may improve the efficiency of the amplifier, keeping good linearity. In this study a DC-DC power converter design suitable for high-frequency applications by using a class E power amplifier (Inverter), instead of using small battery values choosing Radio Frequency (RF) values and getting high efficiency of output voltage and a maximum of current and voltage values between 0-9 mW of power input in rectifier, the class E power amplifier designed by using GaN HEMT device and the power added efficiency of 64% after getting optimization of matching network and the gain is 14.4 dBm.

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30

Tillman, R. H., S. W. Ellingson e J. Brendler. "Practical Limits in the Sensitivity-Linearity Trade-off for Radio Telescope Front Ends in the HF and VHF-low Bands". Journal of Astronomical Instrumentation 05, n.º 02 (31 de maio de 2016): 1650004. http://dx.doi.org/10.1142/s2251171716500045.

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Radio telescope front ends must have simultaneously low noise and sufficiently-high linearity to accommodate interfering signals. Typically these are opposing design goals. For modern radio telescopes operating in the HF (3–30[Formula: see text]MHz) and VHF-low (30–88[Formula: see text]MHz) bands, the problem is more nuanced in that front end noise temperature may be a relatively small component of the system temperature, and increased linearity may be required due to the particular interference problems associated with this spectrum. In this paper, we present an analysis of the sensitivity-linearity trade-off at these frequencies, applicable to existing commercially-available monolithic microwave integrated circuit (MMIC) amplifiers in single-ended, differential, and parallelized configurations. This analysis and associated findings should be useful in the design and upgrade of front ends for low frequency radio telescopes. The analysis is demonstrated explicitly for one of the better-performing amplifiers encountered in this study, the Mini-Circuits PGA-103, and is confirmed by hardware measurements. We also present a design based on the Mini-Circuits HELA-10 amplifier, which is better-suited for applications where linearity is a primary concern.

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31

Volkov, A. A., e M. S. Morozov. "Phase Preselector Intended to Suppress Image Frequency in the Radio Receiver". World of Transport and Transportation 20, n.º 1 (17 de dezembro de 2022): 30–35. http://dx.doi.org/10.30932/1992-3252-2022-20-1-4.

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Until now, to suppress the image channel, radio receivers use a frequency preselector consisting of oscillatory circuits of the input device and a radio frequency amplifier. But the frequency preselector does not suppress strongly enough the image frequency. Therefore, two frequency conversions are often used in railway radio communication systems. For example, for station radio communications at frequencies f = 151‒156 MHz, two frequency converters with fpr1 = 24 MHz and fpr2 =1,596 MHz are used, which greatly complicates the design of the receiver.The article proposes to use a phase preselector, which is the second parallel quadrature frequency converter, the signal of which, after passing additional elements, is summed with the signal of the first frequency converter with high suppression of the image frequency. With this method of organising communication, the bandpass phase shifter will be a problematic block in the phase preselector, since it must have a small error Δφ.A bandpass phase shifter made on RC circuits with a minimum phase shift error Δφ = 0,1˚ within a frequency band of 25 kHz is described. In case of increasing the frequency band, the phase shift error remains minimal, but it is necessary to use limiting amplifiers to equalise the amplitudes of the signals at its output. The use of a phase preselector instead of a frequency preselector will help to reduce the intermediate frequency, which will lead to high selectivity, both in the adjacent and image channels with single-sideband modulation, and will also simplify and reduce the cost of the signal receiver.

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32

Yang, Hsin Chia, e Mu Chun Wang. "Extensive 6.0-18.0 GHz Frequency Low Noise Amplifiers Integrated to Form LC-Feedback Oscillators". Advanced Materials Research 225-226 (abril de 2011): 1075–79. http://dx.doi.org/10.4028/www.scientific.net/amr.225-226.1075.

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Low Voltage supplied radio-frequency (RF) CMOS devices by TSMC 0.18 micron process are used for the RF circuit designs of low noise amplifiers. Three components, low noise amplifiers (LNA), Class-E power amplifiers (PA), and LC oscillator simultaneously working at 6.0 to 18.0 GHz, are explored. The scenario combining two matched amplifiers, LNA and PA, and then amplifying the coupled signals from the oscillators is proven to be working. LNA usually runs prior to PA to suppress the noises, and thus the whole set functions like an integrated LNA, whose forward gain may be promoted as high as at least over 40 dB just as expected. At 6.0, 12.0 and 18.0 GHz, magnitudes of both S11 and S22 in the Smith Chart are deliberately tuned to approach to zero as shown. And Noise Figure determined to be 1.175 gives promising integrated circuit.

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33

Ayllon, Natanael, Juan-Mari Collantes, Aitziber Anakabe, Geoffroy Soubercaze-Pun, Stephane Forestier e Dominique Langrez. "Joint RF and large-signal stability optimization of MMIC power combining amplifiers". International Journal of Microwave and Wireless Technologies 5, n.º 6 (8 de agosto de 2013): 683–88. http://dx.doi.org/10.1017/s1759078713000767.

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In this paper, authors report on an enhanced approach for the design of monolithic microwave integrated circuit (MMIC) power combining amplifiers. Commonly used techniques for the stabilization of such circuits are empirical and too conservative. This leads very often to a non-desired degradation of the radio frequency (RF) performances that are inherent to the physical properties of such stabilization networks at the fundamental frequency of operation. The methodology proposed here is based on the use of large-signal optimization processes that combine RF and stability analyses from the early stages of the design. This approach results in an improvement of the RF performances while sufficient stability margins are preserved. The optimization procedure is explained on a Ku-band MMIC power amplifier for space-borne communications.

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34

Ronnow, Daniel, David Wisell e Magnus Isaksson. "Three-Tone Characterization of Nonlinear Memory Effects in Radio-Frequency Power Amplifiers". IEEE Transactions on Instrumentation and Measurement 56, n.º 6 (dezembro de 2007): 2646–57. http://dx.doi.org/10.1109/tim.2007.907958.

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35

Montesinos, Ronald, Corinne Berland, Mazen Abi Hussein, Olivier Venard e Philippe Descamps. "Analysis of RF power amplifiers in LINC systems". International Journal of Microwave and Wireless Technologies 4, n.º 1 (5 de janeiro de 2012): 81–91. http://dx.doi.org/10.1017/s1759078711001085.

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LInear amplification using Non-linear Components (LINC) is an architecture that achieves linear power amplification for radio-frequency (RF) transmitters. This paper describes the impact of RF power amplifiers (PAs) class on the overall system performances. The linearity and efficiency of the LINC transmitter with different PA classes (AB, B, C, D, E, F, F−1, and J) are evaluated and compared, in terms of error vector magnitude (EVM), adjacent channel leakage ratio (ACLR), and power added efficiency (PAE), for a 16QAM modulation having 5.6 dB peak to average power ratio. Simulations are performed using a gallium-nitride high electron mobility transistor (GaN HEMT) for a power amplifier with an output power of 10 W at 900 MHz.

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36

Aller, Daniel G., Diego G. Lamar, Juan Rodriguez, Pablo F. Miaja, Valentin Francisco Romero, Jose Mendiolagoitia e Javier Sebastian. "Adapting Techniques to Improve Efficiency in Radio Frequency Power Amplifiers for Visible Light Communications". Electronics 9, n.º 1 (10 de janeiro de 2020): 131. http://dx.doi.org/10.3390/electronics9010131.

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It is well known that modern wireless communications systems need linear, wide bandwidth, efficient Radio Frequency Power Amplifiers (RFPAs). However, conventional configurations of RFPAs based on Class A, Class B, and Class AB exhibit extremely low efficiencies when they manage signals with a high Peak-to-Average Power Ratio (PAPR). Traditionally, a number of techniques have been proposed either to achieve linearity in the case of efficient Switching-Mode RFPAs or to improve the efficiency of linear RFPAs. There are two categories in the application of aforementioned techniques. First, techniques based on the use of Switching-Mode DC–DC converters with a very-fast-output response (faster than 1 µs). Second, techniques based on the interaction of several RFPAs. The current expansion of these techniques is mainly due to their application in cellphone networks, but they can also be applied in other promising wireless communications systems such as Visible Light Communication (VLC). The main contribution of this paper is to show how Envelope Tracking (ET), Envelope and Elimination (EER), Outphasing, and Doherty techniques can be helpful in developing more efficient VLC transmitters capable of reaching high bit-rates (higher than 1 Mbps) by using advance modulation schemes. Finally, two examples based on the application of the Outphasing technique and the use of a Linear-Assisted Envelope Amplifier (EA) to VLC are presented and experimentally verified.

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37

Sombrin, Jacques B. "Optimization criteria for power amplifiers". International Journal of Microwave and Wireless Technologies 3, n.º 1 (fevereiro de 2011): 35–45. http://dx.doi.org/10.1017/s1759078710000863.

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This paper describes existing and new criteria for comparison and optimization of non-linear power amplifiers such as RF or microwave transmitters. In addition to intermodulation, receiver noise, and losses in the transmission system, the proposed new criteria take into account efficiency or consumed power. This results in the global optimization of a combined signal-to-noise-plus-intermodulation ratio as a function of saturated or nominal power but also consumed or dissipated power. Saturated power is limited by available technology. Consumed power and dissipated power are some of the main constraints in telecommunication satellite payloads, mobile phone handsets, and RFID (Radio Frequency IDentification). Another constraint comes from the limited size of antennas, which limits the system equivalent isotropic radiated power and gain-to-temperature ratio. With the proposed criteria the designer will be able to compare different amplifier technologies and to optimize the design and operating point of each stage of a multistage amplifier or a linearizer for a given amplifier. Interference from same or other systems is also introduced in the optimization through the use of signal-to-noise-plus-IM-plus-interference ratio criteria.

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38

Cui, Xingli, Xin Qiu, Yongqing Leng, Xiaotian Liu e Tianyu Wu. "A Maximum Efficiency-86% Hybrid Power Modulator for 5G New Radio(NR) Applications". Applied Sciences 12, n.º 23 (25 de novembro de 2022): 12041. http://dx.doi.org/10.3390/app122312041.

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A hybrid power modulator is presented for the radio frequency (RF) power amplifiers of 5th generation mobile communication technology (5G) new radio (NR) applications. A hybrid power modulator utilizing a two-level switching converter and a broadband and high-efficiency linear amplifier is presented. A further improvement in the efficiency of the circuit is achieved by using an optimized supply voltage of the two-level switching converters of 4.5 V. In this way, the overall efficiency is improved by more than 5% compared to using a 5 V supply voltage. The linear amplifier consists of four stages. In order to improve bandwidth and circuit stability, a compensation circuit is added to the linear amplifier that eliminates the poles of the main amplifier by introducing additional zeros, indirectly pushing the pole distribution out of the bandwidth. Using this approach, the linear amplifier achieves a 3-dB bandwidth of 180 MHz and an efficiency of 51%. The hybrid power modulator achieves a maximum output power of 2.4 W and an efficiency of 86% when tracking a 100 MHz 5G-NR signal under a 4 Ω load in a 180 nm CMOS package.

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39

Sarker, Md, e Ickhyun Song. "Design and Analysis of fT-Doubler-Based RF Amplifiers in SiGe HBT Technology". Electronics 9, n.º 5 (8 de maio de 2020): 772. http://dx.doi.org/10.3390/electronics9050772.

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For performance-driven systems such as space-based applications, it is important to maximize the gain of radio-frequency amplifiers (RFAs) with a certain tolerance against radiation, temperature effects, and small form factor. In this work, we present a K-band, compact high-gain RFA using an fT-doubler topology in a silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) technology platform. The through-silicon vias (TSVs), typically used for small-size chip packaging purposes, have been effectively utilized as an adjustable matching element for input impedance, reducing the overall area of the chip. The proposed RFA, fabricated in a modest 0.35 µm SiGe technology, achieves a gain of 14.1 dB at 20 GHz center frequency, and a noise figure (NF) of 11.2 dB at the same frequency, with a power consumption of 3.3 mW. The proposed design methodology can be used for achieving high gain, avoiding a complex multi-stage amplifier design approach.

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40

Lee, Y. H., Y. Chong e Y. K. Semertzidis. "Review of low-noise radio-frequency amplifiers based on superconducting quantum interference device". Progress in Superconductivity and Cryogenics 16, n.º 4 (31 de dezembro de 2014): 1–6. http://dx.doi.org/10.9714/psac.2014.16.4.001.

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41

Bassoo, V., L. Linton e M. Faulkner. "Analysis of distortion in pulse modulation converters for switching radio frequency power amplifiers". IET Microwaves, Antennas & Propagation 4, n.º 12 (2010): 2088. http://dx.doi.org/10.1049/iet-map.2010.0079.

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42

JAIN, AKHILESH, D. K. SHARMA, A. K. GUPTA, P. R. HANNURKAR e S. K. PATHAK. "Compact solid state radio frequency amplifiers in kW regime for particle accelerator subsystems". Sadhana 38, n.º 4 (agosto de 2013): 667–78. http://dx.doi.org/10.1007/s12046-013-0154-0.

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43

Mao, Yuzhou, Shuai Yuan, Yanping Zhao, Gen Chen, Lei Wang, Xu Deng, Diye Xue et al. "Development of the High Radio Frequency Power Amplifiers for ICRF Heating in EAST". Fusion Science and Technology 61, n.º 3 (abril de 2012): 216–26. http://dx.doi.org/10.13182/fst61-216-226.

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44

Memon, M. I., M. Siraj, H. Fathallah e M. S. Khan. "Radio Frequency Generator Using Four Wave Mixing in Cascaded Nonlinear Semiconductor Optical Amplifiers". Acta Physica Polonica A 129, n.º 4 (abril de 2016): 832–34. http://dx.doi.org/10.12693/aphyspola.129.832.

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45

Lu, X. "An alternative approach to improving the efficiency of high power radio frequency amplifiers". IEEE Transactions on Broadcasting 38, n.º 2 (junho de 1992): 85–89. http://dx.doi.org/10.1109/11.142658.

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46

Gamkrelidze, S. A., D. L. Gnatyuk, O. S. Matveenko, S. A. Bugaev, R. R. Galiev, A. V. Zuev, D. V. Lavrukhin et al. "Development of Monolithic Integrated Circuits on Gallium Nitride Heterostructures". Nano- i Mikrosistemnaya Tehnika 24, n.º 2 (21 de fevereiro de 2022): 55–66. http://dx.doi.org/10.17587/nmst.24.55-66.

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The article describes IUHFSE RAS experience in designing MMICs based on gallium nitride heterostructures on various types of substrates: sapphire, silicon and silicon carbide in the frequency range from 10 GHz to 96 GHz. Such as power amplifiers, low-noise amplifiers, and a chipset for radio communications and radiolocation: voltage-controlled oscillators, mixers, multi¬pliers, and transceiver MMIC with integrated antennas. HEMT transistors based on gallium nitride are a suitable for creating a radiation resistant components for frequencies up to 100 GHz.

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47

Sak, P. V. "Integrated estimation of parameters of radio transmitter power amplifier with automatic mode adjustment by two-frequency test signal". Omsk Scientific Bulletin, n.º 176 (2021): 59–64. http://dx.doi.org/10.25206/1813-8225-2021-176-59-64.

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Comparative estimation of energy parameters of power amplifiers of single-band radio transmitters using automatic mode adjustment using a deterministic two-frequency test signal instead of a random single-band signal modulated by speech is investigated in the work. Relationships are found that allow judging the power consumption of the terminal stage of the power amplifier with automatic mode adjustment under various types of modulation based on the results of measurements obtained during tests. The ratios between the power consumption of the output stage when amplifying the random speech signal and amplifying the deterministic two-frequency test signal are obtained both without taking into account losses in the controlled power supply and taking into account such losses. Method is proposed for calculation of energy gain and efficiency factor (efficiency) when applying automatic control of supply voltage of output cascades of shortwave transmitters intended for modulation with speech signals. The loss in the regulated power supply has been estimated. The advantage of power amplifier circuits with automatic mode adjustment is justified

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48

Rehman, Saeed Ur, Shafiq Alam e Iman T. Ardekani. "An Overview of Radio Frequency Fingerprinting for Low-End Devices". International Journal of Mobile Computing and Multimedia Communications 6, n.º 3 (julho de 2014): 1–21. http://dx.doi.org/10.4018/ijmcmc.2014070101.

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RF fingerprinting is proposed as a means of providing an additional layer of security for wireless devices. A masquerading or impersonation attacks can be prevented by establishing the identity of wireless transmitter using unique transmitter RF fingerprint. Unique RF fingerprints are attributable to the analog components (digital-to-analog converters, band-pass filters, frequency mixers and power amplifiers) present in the RF front ends of transmitters. Most of the previous researches have reported promising results with an accuracy of up to 99% using high-end receivers (e.g. Giga-sampling rate oscilloscopes, spectrum and vector signal analysers) to validate the proposed techniques. However, practical implementation of RF fingerprinting would require validation with low-end (low-cost) devices that also suffers from impairments due to the presence of analog components in the front end of its receiver. This articles provides the analysis and implementation of RF fingerprinting using low-cost receivers and challenges associated with it.

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49

Ragonese, Egidio. "Design Techniques for Low-Voltage RF/mm-Wave Circuits in Nanometer CMOS Technologies". Applied Sciences 12, n.º 4 (17 de fevereiro de 2022): 2103. http://dx.doi.org/10.3390/app12042103.

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This paper reviews state-of-the-art design approaches for low-voltage radio frequency (RF) and millimeter-wave (mm-wave) CMOS circuits. Effective design techniques at RF/mm-wave frequencies are described, including body biasing in fully depleted (FD) silicon-on-insulator (SOI) CMOS technologies and circuit topologies based on integrated reactive components (i.e., capacitors, inductors and transformers). The application of low-voltage design techniques is discussed for the main RF/mm-wave circuit blocks, i.e., low-noise amplifiers (LNAs), mixers and power amplifiers (PAs), highlighting the main design tradeoffs.

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50

Giofrè, Rocco, Paolo Colantonio, Franco Giannini, Chiara Ramella, Vittorio Camarchia, Mustazar Iqbal, Marco Pirola e Roberto Quaglia. "A comprehensive comparison between GaN MMIC Doherty and combined class-AB power amplifiers for microwave radio links". International Journal of Microwave and Wireless Technologies 8, n.º 4-5 (11 de fevereiro de 2016): 673–81. http://dx.doi.org/10.1017/s175907871600012x.

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A combined class-AB and a Doherty power amplifier conceived for microwave backhaul in the 7 GHz frequency band are here presented and compared. They are fabricated in the same GaN monolithic process and have identical total active device periphery. For the given application, the linearity-efficiency trade-off for the two architectures is discussed. The two modules have been thoroughly characterized in linear and non-linear continuous wave conditions. Then, to evaluate linearity under the actual operative conditions, a system level characterization has been carried out, applying a modulated input signal and comparing the spectral responses of the two amplifiers with and without digital predistortion. A saturated output power of 40 dBm has been achieved by both circuits. At 6 dB of output back-off, the Doherty amplifier shows an efficiency of 33%, 10 points higher than that of the class-AB module. On the other hand, system level measurements show that, adopting the same predistorter complexity to comply with the reference standard emission masks, the Doherty amplifier needs at least 1 dB of extra back-off. This negatively affects its efficiency, therefore reducing the advantages it can claim with respect to the class-AB amplifier in continuous wave condition.

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