Investigation of class
            <i>J</i>
            continuous mode for high‐power solid‐state RF amplifier

Jain, Akhilesh; Hannurkar, P.R.; Pathak, S. K.; Sharma, Deepak Kumar; Gupta, Alok Kumar

doi:10.1049/iet-map.2012.0649

Cited by 21 publications

(12 citation statements)

References 19 publications

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“…The efforts proceed for better efficiency and output power at component level. However, we still need to improve the reliability and system efficiency causing from the imbalance both in phase and amplitude at system level, which affects the basic parameters of output power such as efficiency and output reflection coefficient [19][20][21][22].…”

Section: Resultsmentioning

confidence: 99%

Long term stability of 1.3 GHz high power RF amplifier

Karslı¹,

Colak²

2021

Turk J Elec Eng & Comp Sci

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Turkish Accelerator and Radiation LAboratory (TARLA) is an accelerator based oscillator mode free electron laser (FEL) facility under construction. The acceleration beam-line includes a fundamental buncher (FB) in order to confine the electron beam into a compressed bunch. In this study, we demonstrate the commissioning tests of 500 W RF amplifier powering FB and present the phase stability dependence of the pressure and temperature of the water cooling line under long time run conditions. As the disturbing effects break down the synchronization between the particle and RF power during acceleration, the reasons disquieting the stability of the RF amplifier are investigated. One reason which disturbs the stability is the variation in the phase of the output power. Phase variation of the output power of the RF amplifier measured as ∼ 10 deg/ • C in average initially, which is beyond permitted variation levels by the controller electronics, namely the Low Level RF system (LLRF), is decreased to less than ∼ 0.45 deg/ • C by incorporating a phase shifter. In addition, this phase variation reduction is accompanied with a reflected power at the output of the RF amplifier decline from 4.3 W (36.33 dBm) down to 3 mW (4.7 dBm) by utilizing a circulator, which is also important and desirable in terms of protection of the electronics in the long term run. As ensuring phase stability in the output power is very important, this work may serve as a guide since the documentation regarding the output power dependence of the water cooling line for long term run is very limited.

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Section: Resultsmentioning

confidence: 99%

Long term stability of 1.3 GHz high power RF amplifier

Karslı¹,

Colak²

2021

Turk J Elec Eng & Comp Sci

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“…The Class‐J mode is usually biased as Class‐B or deep Class AB PA whereby the transistor functions as a current generator such that the RF current waveform is a half‐wave rectified sinewave . The matching network is low pass filter structures aimed at blocking all components of harmonics than the fundamental.…”

Section: Class‐j Power Amplifier Theorymentioning

confidence: 99%

High‐power broadband graphene non‐Foster circuit enabled class‐J GaN HEMT power amplifier

Akwuruoha

2018

Micro & Optical Tech Letters

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This paper presents high-power broadband graphene non-Foster circuit (NFC) enabled Class-J GaN HEMT power amplifier (PA). A graphene resonant-tunneling diode (RTD) NFC is proposed to provide negative differential resistance characteristics and to create an effective negative capacitance. The NFC is integrated in the input matching network of the Class-J GaN HEMT PA to cancel out the transistor input parasitic capacitance so as to enhance PA bandwidth, efficiency, output power, and gain. The PA design is based on Cree's packaged GaN HEMT CGHV40030F biased with drain supply voltage of 50 V at quiescent drain-to-source current of 44 mA. The PA operates from 3.4 to 4.0 GHz with center frequency of 3.7 GHz. The effective negative capacitance of the NFC from 3.4 to 4.0 GHz stands at −3.3 to −6.0 pF. An effective capacitance of −3.7 pF has been obtained at 3.7 GHz. The PA has small signal gain of 16.1 dB at 3.7 GHz. Large signal simulation input power sweep from 1 to 33 dBm at 3.7 GHz, indicates that the PA has 57.8% drain efficiency, 54.7% power added efficiency (PAE), 44.6 dBm (28.8 W) output power and 11.6 dB transducer power gain at input power of 33 dBm. K E Y W O R D S broadband, class-J, GaN HEMT power amplifier, graphene non-Foster circuit, high power

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“…Traditional designs for impedances transformers used lumped elements, twisted wire pairs and ferrite cores to realize an impedance transformation between the input port and one or more output ports . Likewise, the semi‐rigid coaxial cable has been used to realize impedance transformers in countless amplifiers, especially together with LDMOS transistors . Both solutions are limited in terms of cut‐off frequency, either because of losses in the material or the physical dimensions limiting the options for mounting the component.…”

Section: Broadside Coupled Impedance Transformermentioning

confidence: 99%

Double octave L- and S-band power amplifier utilizing broadside coupled impedance transformers

Preis

2015

Int J RF and Microwave Comp Aid Eng

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In this article, the recently revived impedance transformer, implemented as broad side coupled microstrip structure, is used to realize a double octave wideband power amplifier covering the L-and S-band. Several parameters of the transformer, such as distance to a ground plane or permittivity of the dielectric surrounding the transformer are analyzed. The manufactured amplifier, using a commercial GaN HEMT transistor, achieved a continuous wave output power of 45 to 47 dBm and drain efficiency of 42 to 49 percent, respectively. To prove the usability of the concept, linearity measurements were performed, using LTE, WiMAX, and WCDMA signals with up to 10 MHz bandwidth at several center frequencies. ACLR results of 245 dBc are achieved using linearization, as well as an average PAE of up to 29 percent. V C 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:209-216, 2016.

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Investigation of class J continuous mode for high‐power solid‐state RF amplifier

Cited by 21 publications

References 19 publications

Long term stability of 1.3 GHz high power RF amplifier

Long term stability of 1.3 GHz high power RF amplifier

High‐power broadband graphene non‐Foster circuit enabled class‐J GaN HEMT power amplifier

Double octave L- and S-band power amplifier utilizing broadside coupled impedance transformers

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