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by Zachary D. Schwartz and George E. Ponchak

A SiC Clapp oscillator fabricated on an alumina substrate with chip capacitors and spiral inductors is designed for high temperature operation at 1 GHz. The oscillator operated from 30 to 200 ºC with an output power of 21.8 dBm at 1 GHz and 200 ºC. The efficiency at 200 ºC is 15 %. The frequency variation over the temperature range is less than 0.5 %.
Article 01 Nov 2005
by Jorge Moreno Rubio, Jie Fang, R. Quaglia, V. Camarchia, M. Pirola, S. Donati Guerrieri, G. Ghione

The design, implementation and characterization of a Doherty Power Amplifier (DPA) for 3.5 GHz WiMAX applications are discussed. The DPA has been implemented using a commercial GaN HEMT from Cree inc., following a class AB and C scheme for the main and peak module, respectively.
Design 01 Apr 2011
by Jorge Moreno Rubio; Jie Fang; Vittorio Camarchia; Roberto Quaglia; Marco Pirola; Giovanni Ghione

We discuss the design, realization and experimental characterization of a GaN-based hybrid Doherty power amplifier for wideband operation in the 3–3.6-GHz frequency range. The design adopts a novel, simple approach based on wideband compensator networks. Second-harmonic tuning is exploited for the main amplifier at the upper limit of the frequency band, thus improving gain equalization over the amplifier bandwidth.
Design 01 Jun 2012
by Caroline W. Waiyaki

Report for US Army Research Laboratory. A key component of microwave telecommunication systems is the power amplifier (PA). The design parameters of a communication system, such as link performance, power budget, and thermal design are typically driven by the power amplifier’s linearity, output power, and efficiency.
Design 01 Sep 2010
by Raymond S. Pengelly, William Pribble, Thomas Smith

This Simulation of power amplifiers (PAs) for modern wireless base station and small cell systems is an essential part of the design process. At a cell site, the PA consumes the bulk of the dc power, generates the most heat, and thus represents the greatest operational cost. Maximum PA efficiency is a necessity to manage these costs, which is a sizeable challenge in a PA that also must be highly linear to support the complex multilevel modulation types and wide bandwidths used for current and developing wireless transmission standards. Accurate simulation allows
the PA designer to meet these challenges by exploring the available design options and then optimizing the circuit that is selected for the application.
Design 12 Dec 2014
by R. M. Smith, J. Lees, P. J. Tasker, J. Benedikt and S. C. Cripps

A high-efficiency push-pull power amplifier has been designed and measured across a bandwidth of 250MHz to 3.1GHz. The output power was 46dBm with a drain efficiency of above 45% between 700MHz and 2GHz, with a minimum output power of 43dBm across the entire band. In addition, a minimum of 60% drain efficiency and 11dB transducer gain was measured between 350MHz and 1GHz. The design was realized using a coaxial cable transmission line balun, which provides a broadband 2:1 impedance transformation ratio and reduces the need for bandwidth-limiting conventional matching. The combination of output power, bandwidth and efficiency are believed to be the best reported to date at these frequencies.
Design 01 Jun 2012
by L. Cabria, P. M. Cabral, J. C. Pedro, and J. A. García

This paper describes the design of a class E PA destined to be used as the final stage of a polar transmitter under IEEE 802.16e Mobile WiMAX signal excitation. Based on a 60 W GaN HEMT device, the load condition for optimum efficiency is set close to the maximum value of the power generating function for an OFDMA modulating signal.
Design 01 Feb 2010
by David A. Calvillo; Leo C.N. de Vreede; Michel de Langen

A power-scalable, efficient and very wideband GaN class-E high-power amplifier is described. The large bandwidth performance is achieved by employing the so-called “class-E with parallel-circuit” loading conditions using a very compact all-lumped element implementation. The fundamental loading is realized by the magnetizing inductance of a novel bondwire-based transformer connected directly at the transistor drain. The PA input and output matching networks are entirely implemented with bondwire inductors and MOS/MIM capacitors.
Design 01 Dec 2011
by Raymond S. Pengelly

This paper demonstrates the use of optimized analytical procedures to design lossy Class E amplifiers at 1 and 2 GHz using Si LDMOS FETs and SiC MESFETs respectively. The designs use new large-signal models for the LDMOS FETs and SiC MESFETs which provide accurate simulations in both deep sub-threshold (Class C) and fully RF driven "on" states.
Design 15 Apr 2004
by Deniz Gezmiş Tas; Osman Ceylan; H. Bülent Yağcı

In this article, an RF power amplifier which has a crucial importance for RF transceivers is designed and implemented. The main aim of the design is making the power amplifier linear at the center frequency 1.8 GHz. Linearity was measured with two tone test and according to the result of the test, the Carrier-to-Intermodulation (C/I) ratio should have been above 30 dB and two fundamental carriers with the 5 MHz space should be at least 1.25 Watt. Also, efficiency was tried to be kept as high as possible.
Design 01 Sep 2012
by David Schmelzer and Stephen I. Long

A Class F amplifier has been designed, fabricated, and tested using a GaN HEMT transistor and a hybrid PCB.
Design 12 Nov 2006
by Ellie Cijvat, Kevin Tom, Mike Faulkner, and Henrik Sjöland

This paper describes the design, simulation and measurement of a GaN power amplifier suitable for envelope and phase signal combination.
Design 01 Nov 2007
by William L. Pribble, Jim M Milligan, and Raymond S. Pengelly

Abstract from the 2006 IEEE Topical Workshop on PAs for Wireless Communications (RWS)
Presentation from the 2006 IEEE Radio and Wireless Symposium in San Diego
A class-E power amplifier based on a GaN HEMT cell has been designed and tested.
Design 17 Jan 2006
by William L. Pribble, Jim M Milligan, and Raymond S. Pengelly

Abstract from the 2006 IEEE Topical Workshop on PAs for Wireless Communications (RWS)
Presentation from the 2006 IEEE Radio and Wireless Symposium in San Diego
A class-E power amplifier based on a GaN HEMT cell has been designed and tested.
Design 17 Jan 2006
by Ray Pengelly, Simon Wood, Jim Crescenzi

This article describes a WiMAX power amplifier, which achieves high performance using the latest device technologies and design techniques.
Article 01 Dec 2008
by Simon M. Wood, Raymond S. Pengelly, William L. Pribble, Dustin E. Hoekstra

Abstract from the 2006 IEEE Topical Workshop on PAs for Wireless Communications (RWS)
Presentation from the 2006 IEEE Radio and Wireless Symposium in San Diego
This paper describes the results of a broadband, high linearity, high efficiency power amplifier for WiMAX basestation applications in the 3.3 - 3.9 GHz band.
Design 17 Jan 2006
by Simon M. Wood, Raymond S. Pengelly, William L. Pribble, Dustin E. Hoekstra

Abstract from the 2006 IEEE Topical Workshop on PAs for Wireless Communications (RWS)
Presentation from the 2006 IEEE Radio and Wireless Symposium in San Diego
This paper describes the results of a broadband, high linearity, high efficiency power amplifier for WiMAX basestation applications in the 3.3 - 3.9 GHz band.
Design 17 Jan 2006
by Bumjin Kim, D. Derickson, and C. Sun

A class B and a class F power amplifier are described using a GaN HEMT device.
Design 01 Dec 2007
by Andrei Grebennikov

In this paper, a novel high-efficiency four-stage Doherty power amplifier architecture convenient for practical implementation in base station applications for modern communication standards has been proposed and fabricated.
Design 01 Apr 2011
by Marco J. Pelk, W. C. Edmund Neo, John R. Gajadharsing, Raymond S. Pengelly, Leo C. N. de Vreede

A three-way Doherty 100-W GaN base-station power amplifier at 2.14 GHz is presented.
Design 15 May 2008
by Philip A. Godoy, SungWon Chung, Taylor W. Barton, David J. Perreault, and Joel L. Dawson

A 1.95-GHz asymmetric multilevel outphasing (AMO) transmitter with class-E GaN power amplifiers (PAs) and discrete supply modulators is presented.
Design 01 Jun 2011
by Junghwan Son, Ildu Kim, Junghwan Moon, Juyeon Lee, Bummam Kim

An asymmetric Doherty Power Amplifier (ADPA) is introduced using a new output combining circuit for easy of implementation with a large matching tolerance. The proposed APDA has been implemented using GaN HEMT devices at 2.6 GHz for WiMAX signal with 5MHz bandwidth and 8.3 dB peak to average power ratio.
Design 01 Nov 2011
by Junghwan Moon, Young Yun Woo, Bummam Kim

A novel design of the Doherty power amplifier (PA) to improve the efficiency at a back-off output power level.
Design 01 Sep 2009
by Christian Musolff; Michael Kamper; Zeid Abou-Chahinel; Georg Fischer

This article outlines the design procedure and presents the results of the winning power amplifier (PA) design at the PA competition held at the 2012 IEEE MTT-S International Microwave Symposium (IMS2012) and sponsored by the High-Power Microwave Components Committee (MTT-5).

Design 01 Jan 2013
by David Yu-Ting Wu and Slim Boumaiza

A new Doherty amplifier configuration with an intrinsically broadband characteristic is presented based on the synthesis of key ideas derived from the analyses of the load modulation concept and the conventional Doherty amplifier. Important building blocks to implement the proposed Doherty amplifier structure are outlined, which include the quasi-lumped quarter-wave transmission line, as well as the Klopfenstein taper for broadband impedance matching.
Design 01 Oct 2012
by Moon, Junghwan Son, Juyeon Lee, Jungjoon Kim, Seunghoon Jee, Seungchan Kim, and Bumman Kim

A multimode/multiband envelope tracking (ET) transmitter consisting of a hybrid switching amplifier (HSA) and a broadband saturated power amplifier (PA) is developed across 1.3 to 2.7 GHz.
Design 01 Jun 2011
by Sheikh Nijam Ali, Thomas Johnson

A new architecture for RF switch-mode power amplifiers is proposed. In this design, a pulse encoded signal switches a single RF power device with a broadband output match coupled to an output diplexer. The broadband termination impedance across the device minimizes switching losses.
Design 01 Apr 2012
by Jangheon Kim, Junghwan Moon, Jungjoon Kim, Slim Boumaiza, and Bumman Kim

A novel design method without requiring the special harmonic termination circuit for a highly efficient power amplifier (PA) is proposed.
Design 01 Sep 2009
by V. Carrubba, J. Lees, J. Benedikt, P. J. Tasker, S. C. Cripps

A novel, highly efficient and broadband RF power amplifier (PA) operating in “continuous class-F” mode has been realized for first time.
Design 01 Jun 2011
by Raymond S. Pengelly, Simon M. Wood, James W. Milligan, Scott T. Sheppard, and William L. Pribble
Design 01 Jun 2012
by Jangheon Kim, Junghwan Moon, Bumman Kim, and Raymond S. Pengelly

This article presents the design of the winning PA with PAE of 73.2% at 3.2GHz operating frequency, which is equivalent to the weighted PAE performance of 97.9% by students from Pohang University of Science and Technology (POSTECH).
Article 01 Feb 2009
by Neal Tuffy; Lei Guan; Anding Zhu; Thomas J Brazil

This paper describes the design approach employed for achieving approximated continuous Class-F power amplifier (PA) modes over wide bandwidths. The importance of the nonlinear device capacitance for wave-shaping the continuous Class-F voltage and current waveforms is highlighted, thus reducing the device sensitivity to second and third harmonic impedance terminations.
Design 01 Jun 2012
by Reinel Marante, M. Nieves Ruiz, Leysi Rizo, Lorena Cabria, José A. García

In this paper, the design of a class E2 resonant DC/DC converter, operating at UHF band, is proposed. Combining the use of GaN HEMT devices, both for the inverter and the synchronous rectifier, with high Q lumped-element multi-harmonic matching networks, a peak efficiency value of 72% has been obtained at 780 MHz with a 10.3 W output power.
Design 01 Jun 2012
by Yong-Sub Lee, Mun-Woo Lee, Sang-Ho Kam, and Yoon-Ha Jeong

This paper reports a new double Doherty power amplifier (DDPA) with a flat efficiency range, which consists of two-stage amplifiers.
Design 01 May 2010
by Bumman Kim, Ildu Kim, Junghwan Moon

This article describes the design of a GaN Doherty power amplifier with digital pre-distortion as well as hybrid envelop elimination and restoration / envelop tracking technique (H-EER/ET).
Article 01 Aug 2010
by Simon Wood, Carl Platis, Don Farrell, Brad Millon, Bill Pribble, Peter Smith, Ray Pengelly, and Jim Milligan

This article discusses various uses of Cree’s GaN HEMTs (CGH21120, CGH25120, CGH40120) in standard and novel amplifier topologies. It includes the practical use of Cree’s proprietary large signal models.
Article 01 May 2009
by Ahmed Sayed, Stefan von der Mark and Georg Boeck

A 5-watt wideband power amplifier using a SiC MESFET has been designed. The frequency range covers 10 MHz to 2.4 GHz with small-signal gain of 8 dB. A broadband choke structure with a new technique was developed to obtain good isolation and low loss over the desired bandwidth. Input and output matching networks and shunt feedback topology were introduced to increase the bandwidth.
Design 12 Oct 2004
by Mohamed El-Asmar; Ahmed Birafane; Mohamed Helaoui; Ammar B. Kouki; Fadhel M. Ghannouchi

An analytical design methodology of outphasing amplification systems is proposed using new simplified analytical expressions for the instantaneous efficiency and the input/output voltages of Chireix outphasing combiners. These expressions are derived first for ideal voltage sources with nonzero internal impedance and later for ideal Class-B amplifiers where dc current variation is incorporated. They take into account the impedance mismatch between the amplifiers and the lossless combining structure and account explicitly for the all of the combiner’s electrical parameters.
Design 01 Jun 2012
by D. Kimball, J. Jeong, C. Hsia, P. Draxler, P. Asbeck, D. Choi, W. Pribble and R. Pengelly

Class E amplifiers offer significant advantages for high efficiency operation, although they have been largely limited to relatively low microwave frequencies and/or low output powers. GaN HFETs are well suited to Class E at high powers and high frequencies, inasmuch as their output capacitance is particularly low for a device with a given output power, and has little voltage dependence.
Design 17 Jan 2006
by Raymond S. Pengelly, Brad Millon, Donald Farrell, Bill Pribble, and Simon Wood

Presentation from the 2008 IEEE MTT-S International Microwave Symposium (IMS) Workshop on Challenges in Model-Based HPA Design

This presentation discusses attributes of GaN HEMTs, Cree GaN HEMT models, design examples (Broadband CW Amplifiers and Linear WiMAX Amplifier), and future model improvements.
Design 16 Jun 2008
by Michael Boers

Michael Boers, Ph.D. Student, Wins IEEE MTT-S Power Amplifier Competition, 85% PAE Achieved with Microwave Office and Cree, Inc. GaN HEMT.
Article 01 Jul 2007
by George Fischer

This paper focuses on how specific characteristics of wide band gap RF power transistors at device level map to benefits at architectural level with those frequency agile systems.
Design 15 Apr 2004
by Junghwan Moon; Seunghoon Jee; Jungjoon Kim; Jangheon Kim; Bumman Kim

Operational behaviors of the class-F and class-F amplifiers are investigated. For the half-sinusoidal voltage waveform of the class-F amplifier, the amplifier should be operated in the highly saturated region, in which the phase relation between the fundamental and second harmonic currents are out-of-phase. The class-F amplifier can operate at the less saturated region to form a half sinewave current waveform. Therefore, the class-F amplifier has a bifurcated current waveform from the hard saturated operation, but the class-F amplifier operates as a switch at the saturated region for a second harmonic tuned half-sine waveform.
Design 01 Jun 2012
by Guolin Sun, Rolf H. Jansen

A comprehensive method of designing a broadband Doherty power amplifier is presented in this paper. The essential limitations of bandwidth extension of a Doherty power amplifier are discussed based on the proposed structure of the Doherty power amplifier, which also takes the output matching networks of both sub-amplifiers into account. The broadband matching is realized by applying the simplified real frequency technique with the desired frequency dependent optimum impedances. GaN transistors were selected to implement the circuit structure.
Design 01 Jan 2012
by Caleb Fulton, William J. Chappell

This paper discusses the challenges of polarimetric phased array calibration, and demonstrates these techniques using a linear array of eight S-band dual-polarized antennas connected to an active Digital Array Radar (DAR) prototype system.
Design 01 May 2010
by J. A. García, B. Bedia, R. Merlín, P. Cabral and J. C. Pedro

An experimental procedure is proposed for accurately characterizing the Vdd-to-AM and Vdd-to-PM nonlinearities in a Class E power amplifier (PA). Based on GaN HEMT technology,...
Design 01 Dec 2007
by Marc Franco and Allen Katz

This paper investigates the use of silicon carbide (SiC) metal-semiconductor field effects transistors (MESFETs) in high-efficiency, class-E, RF power amplifiers in the VHF range. A maximum drain DC to RF efficiency of 87% was predicted and 86.8% achieved.
Design 05 Jun 2007
by Neal Tuffy, Anding Zhu, and Thomas J. Brazil

This work outlines a design approach used for achieving highly efficient power amplification over a wide bandwidth, given narrowband passive harmonic load-pull results at a single center frequency.
Design 01 Jun 2011
by Kenle Chen, Xiaoguang Liu, William J. Chappell and Dimitrios Peroulis

A unique GaN power amplifier (PA) with an integrated evanescent-mode resonator as its output matching network is presented in this paper.
Design 01 Jun 2011
by Sang Hoon Kim, Hyoung Jong Kim, Suk Woo Shin, Jae Duk Kim, Bo Ki Kim and Jin Joo Choi

This paper proposes a new configuration for power oscillator based on the combined power amplifier. The focus is on power combining as a oscillator structure with a positive feedback loop line. The proposed configuration consists of a harmonic-tuned combined power amplifier using two Gallium Nitride High Electron Mobility Transistors (CGH40025), 3dB Wilkinson divider/combiner, a directional coupler, an isolator, a coaxial line and mechanical phase shifters.
Design 01 Jun 2011
by Raymond Pengelly, Scott Sheppard, Thomas Smith, Bill Pribble, Simon Wood and Carl Platis

Wide bandgap technology is now finding extended use in switching, control and low noise applications. Cree's GaN on silicon carbide (SiC) MMIC processes provide high drain to source breakdown voltage (typically 150 volts) resulting in robust transistor operation allowing, for example, simpler receiver protection circuitry.
Design 01 May 2011
by David Yu-Ting Wu, Slim Boumaiza

Research on digital predistortion and advanced transmitters utilizing nonlinear PAs have begun to mitigate the concerns about nonlinearity.
Article 01 Feb 2010
Paul Saad; Paolo Colantonio; Junghwan Moon; Luca Piazzon; Franco Giannini; Kristoffer Andersson; Bumman Kim; Christian Fager

This paper presents the design, implementation, and experimental results of a highly efficient concurrent dualband GaN-HEMT power amplifier at 1.8 GHz and 2.4 GHz. A bare-die approach, in conjunction with a harmonic sourcepull/load-pull simulation approach, are used in order to design and implement the harmonically tuned dual-band PA. For a continuous wave output power of 42.3 dBm the measured gain is 12 dB in the two frequency bands; while the power added efficiency is 64% in both bands. Linearized modulated measurements, using concurrently 10MHz LTE and WiMAX signals, show an average PAE of 25% and and adjacent channel leakage ratio of -48 dBc and -47 dBc at 1.8 GHz and 2.4 GHz, respectively.
Design 15 Apr 2012
by Danish Kalim and Renato Negra

This paper presents a concept to design a compact planar multiharmonic load transformation network (MHLTN) for the realisation of highly efficient dual-band power amplifiers (PAs). The topology was applied to implement a class-E PA using a GaN High Electron Mobility Transistor (HEMT) in a hybrid design for GSM1810 and LTE2655 operation.
Design 01 Jun 2011
by Zhebin Wang and Chan-Wang Park

This paper presents a novel method by using resonators in both input and output matching networks to design a tri-band GaN HEMT power amplifier. Two parallel resonators in series as one frequency selection element are used for each operation frequency. By applying this frequency selection element in both input and output matching networks constructed with microstrip line, tri-band matching network is realized. With our proposed frequency selection element, we can use the conventional L-type structure to design matching network for three frequencies so that the design analysis procedure is easier. We also propose a new simplified output matching network by using bias line to match the output impedance to reduce the number of resonators. To demonstrate our method, we fabricate a tri-band power amplifier that can work at 1 GHz, 1.5 GHz, and 2.5 GHz concurrently. Experimental results show that the output power is 39.8 dBm, 40.8 dBm, and 39.2 dBm with 56.4%, 58.3%, and 43.4% power added efficiency (PAE) at 1 GHz, 1.5 GHz and 2.5 GHz, respectively.
Design 15 Apr 2012
by Thomas M. Hone; Souheil Bensmida; Kevin A. Morris; Mark A. Beach; Joe P. McGeehan; Jonathan Lees; Johannes Benedikt; Paul J. Tasker

Mathematical analysis of Doherty amplifiers have assumed many simplifications. Most notably, the peaking amplifier does not contribute power into the load and the peaking stage has an observed impedance of infinity. This paper will show that these simplifications impair the performance of a single-input Doherty amplifier and that phase tuning for compensation is needed to improve the overall system performance.
Design 01 Jun 2012
Microwave office capabilities provide first-pass design success of complex 2.1-GHz circuits using GaN HEMTs.
Articles 01 Jun 2009
by David Sardin, Zoya Popovic

This work discusses the design of a GaN power amplifier demonstrating high efficiency over more than a decade bandwidth using coaxial baluns and transformer matching networks to achieve over a 50 MHz – 500 MHz bandwidth. The power amplifier demonstrates a power added efficiency of 83% - 64% over a full bandwidth with 15 dB compressed gain at peak PAE.
Design 01 Sep 2013
by David Yu-Ting Wu, Farouk Mkadem, Slim Boumaiza

Abstract — A comprehensive approach for designing broadband and highly efficient power amplifier based on optimal impedance analysis and simplified real frequency technique SRFT) is presented.
Design 01 May 2010
by Tian He; Uma Balaji

A Class F power amplifier (PA) at 2.5 GHz has been designed and fabricated. Test results show 15.7 dB gain with 75.75% power added efficiency (PAE ), at an input level of 25 dBm.
Design 01 Feb 2010
by Paul Saad; Paolo Colantonio, Luca Piazzon; Franco Giannini; Kristoffer Andersson; Christian Fager

In this paper, the design, implementation, and experimental results of a high-efficiency dual-band GaN-HEMT Doherty power amplifier (DPA) are presented. An extensive discussion about the design of the passive structures is presented showing different possible topologies of the dual-band DPA. One of the proposed topologies is used to design a dual-band DPA in hybrid technology for the frequency bands 1.8 and 2.4 GHz with the second efficiency peak at 6-dB output power back-off (OBO).
Design 01 Jun 2012
by Zheng, Yuanan Liu, Cuiping Yu, Shulan Li, and Jiuchao Li

This paper proposes a novel design methodology for dual-band Doherty power amplifier(DPA) with simplified offset-lines. The methodology is validated with the design and fabrication of a 10 W GaN based DPA for Global System for Mobile Communications (GSM) and Wideband Code Division Multiple Access (WCDMA) applications at 0.90 GHz and 2.14 GHz, respectively.
Design 31 Dec 2013
by Simon M. Wood and Raymond S. Pengelly

This paper describes the use of a new large signal LDMOS FET model in the design of a high power, UMTS band 60W Doherty amplifier. This new model will be shown to be capable of providing accurate predictions of power, gain, efficiency and most importantly, linearity of the complete amplifier.
Models 15 Apr 2004
by Kenle Chen and Dimitrios Peroulis

This paper presents a novel adaptive power amplier (PA) architecture for performing dynamic-load-modulation. For the rst time, a dynamically-load-modulated PA design that achieves octave bandwidth, high power and high efciency simultaneously is experimentally demonstrated. This PA design is based on a commercial GaN HEMT.
Design 01 Jun 2012
by Anh Nghiem Xuan and Renato Negra

A new technique for designing concurrent multiband biasing networks for multiband RF power amplifiers is presented. The proposed design technique can theoretically be applied for a large number of frequency bands. The biasing network (BN) is composed of a transmission line and high impedance quaterwave open stubs (QWOS) that are located at appropriate positions along the transmission line. Two tri-band BNs for 1.49 GHz, 2.15 GHz and 2.65 GHz frequencies were designed, fabricated and display very good performance with regard to the input impedance seen looking toward the BNs from the active devices, such as FETs, are approximately open for all three bands.
Design 01 Oct 2012
by Bradley J. Millon, Simon M. Wood, Raymond S. Pengelly

2.5 and 5-watt average power (15 and 30-watt peak power) GaN HEMT amplifiers for WiMAX signal protocols have been designed and fabricated for use in the 5.5 to 5.8-GHz band.
Design 27 Oct 2008
by Robert Smith; Professor Steve C. Cripps

Using differential linear measurements, the harmonic impedance conditions presented by simple transmission line baluns are identified. These impedances are shown to differ significantly from the harmonic conditions usually associated with push-pull amplifiers. When taking into account these impedance conditions, a family of waveforms corresponding to the theoretical waveforms inside a push-pull amplifier can be described mathematically and measured using a harmonic load-pull system.
Design 01 Apr 2012
by Kenle Chen, Dimitrios Peroulis

A new methodology for designing and implementing high-efficiency broadband Class-E power amplifiers (PAs) using high-order low-pass filter-prototype is proposed in this paper. A GaN transistor is used in this work, which is carefully modeled and characterized to prescribe the optimal output impedance for the broadband Class-E operation.
Design 01 Apr 2012
by P. Suebsombut, O. Koch, S. Chalermwisutkul

A class-AB power amplifier was designed for an envelope tracking (ET) application. Class-AB amplifier is widely used in wireless communication systems due to the compromise between linearity and efficiency.
Design 01 May 2010
by S. Lin and A. E. Fathy

A 50 to 550 MHz wideband gallium nitride (GaN) HEMT power amplifier with over 43 dBm output power and 63% drain
efficiency has been successfully developed.
Design 01 Jan 2011
by D. E. Root, J. Xu, J. Horn, M. Iwamoto, and G. Simpson

It is demonstrated that Xparameters measured versus load at the fundamental frequency predict well the independent effects of harmonic load tuning on a 10W GaN packaged transistor without having to independently control harmonic loads during characterization.
Design 01 Apr 2010
by Jingqi Wang, Yingjie Xu, and Xiaowei Zhu

In this paper, a digital predistorted inverse class-F GaN power amplifier with novel PAPR reduction technique, in
which not only peaks but also valleys of signal are clipped to reduce the PAPR as much as possible, is presented.
Design 01 Jun 2011
by Gabriel Montoro, Pere Gilabert, Jordi Berenguer, and Eduard Bertran

This paper presents a new Digital Predistorter (DPD) to compensate for nonlinear distortion that arises in Envelope Tracking (ET) Power Amplifiers (PAs) driven by slew-rate limited versions of the real signal’s envelope.
Design 01 Jun 2011
by Junghwan Moon, Junghwan Son, Jungjoon Kim, Ildu Kim, Seunghoon Jee, Young Yun Woo, and Bumman Kim

A Doherty amplifier assisted by a supply modulator is presented using 2.14 GHz GaN HEMT saturated power amplifier (PA). A novel envelope shaping method is applied for high power-added efficiency (PAE) over a broad output power range.
Design 01 May 2010
by Karun Rawat; Mohammad S. Hashmi; Fadhel M. Ghannouchi

The emergence of increasing multifunctionality and high data rate advanced wireless standards, such as WiMAX and LTE-advanced, requires communication systems capable of operating at multiple frequencies simultaneously. This situation has led to scenarios where the radios with the ability to function at several distinct frequencies are required. Seamless transition from one existing standard (e.g., 3G) to upcoming standards (e.g., 4G) with backward compatibility is also a motivating factor for the deployment of multiband radio architectures.
Design 01 Mar 2012
by Junghwan Moon, Juyeon Lee, Junghwan Son, Jungjoon Kim, Seunghoon Jee, Seungchan Kim, and Bumman Kim

The effects of even-order nonlinear terms on ET transmitters are explored for the behavior model and digital predistortion technique.
Design 01 Oct 2011
by Junghwan Moon, Jangheon Kim, Jungjoon Kim, Ildu Kim, Bummam Kim

This paper presents an approach to mitigating the knee voltage effect of the Doherty power amplifier (PA), especially on the carrier amplifier.
Design 01 Jan 2011
by Bumman Kim, Ildu Kim, Junghwan Moon

A general overview and practical design methods for supply-modulated transmitters are presented. Disadvantages of the conventional EER transmitter are discussed, such as wideband sensitivity, power leakage, and poor PAE.
Article 01 Aug 2010
by John W. Palmour

As wide bandgap devices begin to become commercially available, it is becoming clear that electrical efficiency improvement is one of the key drivers for their adoption.
Design 12 Nov 2006
by Hossein Mashad Nemati, Alan L. Clarke, Steve C. Cripps, Johannes Benedikt, Paul J. Tasker, Christian Fager, Jan Grahn, and Herbert Zirath

In this paper, the efficiency of a GaN HEMT transistor and its intrinsic waveforms are measured at 0.9 GHz and investigated for load- and supply-modulation applications.
Design 01 May 2010
by Pere Gilabert; Gabriel Montoro; Eduard Bertran; Jose A. Garcia

This paper presents an exhaustive description of a field programmable gate-array (FPGA) based set-up for envelope tracking and dynamic biasing of RF power amplifiers (PA). For testing purposes a GaN HEMT RF PA operating at 3.5 GHz was considered.
Design 01 Feb 2010
by José A. García, Reinel Marante, María N. Ruiz

In this paper, the design and performance of class E2 resonant topologies for DC/DC power conversion at Ultra High Frequencies (UHF) are considered. Combining the use of RF GaN HEMT devices, both for the inverter and the synchronous rectifier, with high Q lumped-element terminating networks, peak efficiency values over 70% may be obtained.

Control strategies based on carrier bursting, switching frequency modulation, or outphasing are also shown to be feasible. Taking advantage of their improved dynamic response, when compared to low frequency more traditional switched-mode converters, a class E3 polar transmitter for the EDGE standard has been designed and tested at 770 MHz, offering an average global efficiency over 46% at 4.3 W of output power, through RF-based amplitude and phase constituting branches.
design 01 Dec 2012
by MHD. Tareq Arnous; Khaled Bathich; Sebastian Preis; Georg Boeck

In this paper, the design, implementation, and experimental results of a 200 W high efficiency broadband GaN HEMT power amplifier (PA) are presented. Power combining was used to combine the outputs of two individual octave bandwidth 100 W power amplifiers. Optimum fundamental and harmonic load impedances were obtained using load-pull simulations for the active device across the design band. A systematic approach was applied for the design of wideband output and input matching networks.
Design 01 Oct 2012
by Jangheon Kim: Farouk Mkadem; Slim Boumaiza

This paper proposes a new broadband saturated power amplifier (SPA) with a distributed second harmonic termination supporting multi-band/multi-mode operation. Due to the multiple harmonic terminations, the proposed PA improves the frequency range where the PA can achieve a high efficiency.
Design 01 Sep 2010
by Gil Wong Choi, Hyoung Jong Kim, Woong Jae Hwang, Suk Woo Shin, Jin Joo Choi, and Sung Jae Ha

This paper describes the design and fabrication of a highly efficient switching-mode Class-E Doherty power amplifier using gallium nitride (GaN) high electron mobility transistor (HEMT) for S-band radar applications.
Design 01 Jun 2009
by S. Wood, P. Smith, W. Pribble, R. Pengelly, and J. Crescenzi

An article in High Frequency Electronics about the use of Cree's GaN HEMTs for WiMAX applications.
Article 01 May 2006
by U. H. Andre, R. S. Pengelly, A. R. Prejs and S. M. Wood, and E. J. Crescenzi

An article in High Frequency Electronics about the recent advances in the use of Cree's GaN HEMTs for WiMAX applications.
Article 01 Jun 2007
by U.H. Andre, R.S. Pengelly, A.R. Prejs, S.M. Wood, and E.J. Crescenzi

An article in High Frequency Electronics about the recent advances in the use of Cree's GaN HEMTs for WiMAX applications.
Design 01 Jun 2007
by Saptharishi Sriram, Helmut Hagleitner, Dan Namishia, Terry Alcorn, Thomas Smith, and Bill Pulz

We demonstrate for the first time improvement of radio-frequency (RF) gain of SiC MESFETs by using source-connected field plates (FPs).
Design 01 Sep 2009
by Primit Parikh, Yifeng Wu, M. Moore, P. Chavarkar, U. Mishra, R. Neidhard, L. Kehias, T. Jenkins

AlGaN-GaN HEMTs have not only been identified as the technology of choice for next generation high-power, high frequency applications but recently have also garnered interest for low noise receiver applications.
Article 01 Aug 2002
by S. T. Sheppard, R. P. Smith, W. L. Pribble, Z. Ring, T. Smith, S. T. Allen, J. Milligan and J. W. Palmour

An overview of hybrid and monolithic high-power microwave amplifiers using SiC MESFET and GaN HEMT active devices is presented. High power densities of 5.2 W/mm and 63% power added efficiency (PAE) have been demonstrated for SiC MESFETs at 3.5 GHz. This performance has driven the development of wide-bandwidth MMIC amplifiers, which have yielded 37 W of pulsed power at 3.5 GHz.
Design 24 May 2002
by Kelvin Yuk, G.R. Branner and Claudia Wong

A method of determining the optimal harmonic terminations using accurate nonlinear computer models and load- and source-pull simulations is described.
Design 01 May 2010
by Zachary D. Schwartz and George E. Ponchak

A hybrid, UHF-Band differential oscillator based on 10 W SiC RF Power Metal Semiconductor Field Effect Transistor (MESFET) has been designed, fabricated and characterized through 475 °C. The circuit is fabricated on an alumina substrate with thin film spiral inductors, chip capacitors, chip resistors, and wire bonds for all crossovers and interconnects.
Design 11 May 2005
by Andrei Grebennikov

In modern wireless communication systems such as CDMA2000, WCDMA, or OFDM with increased bandwidth and high data rate, the transmit signal is characterized by a high peak-to-average power ratio (PAR) due to wide and rapid variations of the instantaneous transmit power.
Design 01 Feb 2012
by Peter Wright, Aamir Sheikh, Chris Roff, P. J. Tasker and J. Benedikt

Interactive Forum paper from the 2008 International Microwave Symposium (IMS)
Presentation Supplement
This paper investigates the development of an inverse class-F design procedure for obtaining very high efficiency performance at high power levels. RF waveform engineering was used to obtain high efficiency inverse class-F waveforms at the device current-generator plane.
Design 15 Jun 2008
by Junghwan Moon, Juyeon Lee, Bumman Kim, Raymond S. Pengelly, Ryan Baker

The Seventh Student High-Efficiency Power Amplifier (PA) Design Competition was held at the IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium (IMS) 2011 in Baltimore, Maryland. Every year, many students from all over the world participate in the competition and demonstrate their ability to design a high-efficiency PA.
Article 01 Feb 2012
by Woo Lee, Sang-Ho Kam, and Yoon-Ha Jeong

This paper describes a new three-stage Doherty power amplifier (DPA) with an adaptive driving amplifier inserted at the input of the carrier cell.
Design 01 Jun 2011
by Yifeng Wu and Primit Parikh

The vacuum tubes used in today's millimeter-wave transmitters face an increasing threat from GaN HEMTs. Cree's Yifang Wu and Primit Parikh are leading the GaN charge with designs that incorporate field plates, iron-doped buffer layers and a thin AIN interlayer to deliver a record power at 30 GHz.
Article 01 Jan 2006
by Francisco Javier Ortega-Gonzalez, David Tena-Ramos, Moises Patino-Gomez, Jose Manuel Pardo-Martin, Diego Madueno-Pulido

This paper presents a high-power, high-efficiency wideband suboptimum Class-E RF power amplifier based on a packaged high-power GaN HEMT. It uses a simple double-reactance compensation and impedance transformation load network that includes device intrinsic capacitance, package parasitics, low-loss microstrip transmission lines, and lumped components. This load network makes the GaN HEMT operate in suboptimum Class-E from 900 to 1500 MHz (50% fractional bandwidth at 1200 MHz).
Design 01 Jan 2013
by Simon Wood, Ray Pengelly, Don Farrell, and Carl Platis, Cree, Inc., and Jim Crescenzi, Central Coast Microwave Design

New GaN HEMT devices allow the design of high power amplifiers with the desired linearity and efficiency for 4G applications such as WiMAX, UMTS and WCDMA.
Article 01 May 2009
by Troels S. Nielsen, Ulrik R. Madsen, Michael Dieudonné

A complete power amplifier design using new Nonlinear Vector Network Analyzer (NVNA) and X-parameter technologies. A high-power, pulsed Continuous Wave (CW) NVNA setup is presented and harmonic tuning capabilities of the measured X-parameter model is demonstrated using the same setup.
Design 01 Nov 2011
by Simon M. Wood, Ulf Andre, Bradley J. Millon, and Jim Milligan

This paper presents the design, development and characterization of three products for S-Band Radar applications. These products include two 240 Watt hybrid power transistors and a fully integrated 75 Watt packaged MMIC.
Design 01 Oct 2012
by Ildu Kim, Jangheon Kim, Junghwan Moon, Jungjoon Kim, and Bumman Kim

Demonstrating a highly efficient Hybrid Envelope Elimination and Restoration transmitter for IEEE 802.16e Mobile WiMAX applications using a highly efficient saturated Power Amplifier (PA). For the optimum H-EER operation, the PA has been designed to have a maximum PAE at the average Vds region by using 10 W (P3dB ) GaN High Electron Mobility Transistor.
Design 01 Jun 2009
by Pedro P. Vizarreta; Gabriel Montoro; Pere L. Gilabert

This paper presents an envelope tracking (ET) Power Amplifier (PA) whose architecture includes an efficient Envelope Amplifier (EA) and a bandwidth reduction algorithm suitable for real time applications.
Design 01 Oct 2012
by Moon, Seunghoon Jee, Jungjoon Kim, Junghwan Son, Seungchan Kim, Juyeon Lee, Seokhyeon Kim, and Bumman Kim

The practical operating conditions of class-F-1 amplifier are investigated by analyzing the current and voltage waveform shapings. In the experiment, the saturated amplifier is designed and implemented using Cree GaN HEMT CGH40010 at 2.655 GHz. It provides a power-added efficiency of 73.9% at saturated output power of 41 dBm.
Design 01 Oct 2011
by Junghwan Moon; Jungjoon Kim; Bumman Kim

This paper presents the operation principle of Class-J power amplifiers (PAs) with linear and nonlinear output capacitors (Cout s). The efficiency of a Class-J amplifier is enhanced by the nonlinear capacitance because of the harmonic generation from the nonlinear Cout , especially the second-harmonic voltage component.
Design 04 Nov 2010
by Sebastian Preis; Daniel Gruner; Georg Boeck

The class-B/J mode continuum in power amplifiers (PAs) defined at the current source plane is discussed considering different parasitic elements including C DS as well as the package. Based on this realistic device description the change of the continuous load impedances depending on the reference plane is demonstrated. It is shown that the design flexibility predicted by the continuous mode theory decreases if the transistor package is taken into account. The presented investigations provide the basis for the design of a broadband GaN PA.