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NONLINEAR EMBEDDING FOR HIGH EFFICIENCY RF POWER AMPLIFIER DESIGN AND APPLICATION TO GENERALIZED ASYMMETRIC DOHERTY AMPLIFIERS

Jang, Haedong
http://rave.ohiolink.edu/etdc/view?acc_num=osu1406269587

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
A fully model-based nonlinear embedding device model including low and high-frequency dispersion effects is implemented for the Angelov device model and successfully demonstrated for load modulation power amplifier (PA) applications. Using this nonlinear embedding device model, any desired PA mode of operation at the current source plane can be projected to the external reference planes to synthesize the required multi-harmonic source and load terminations. A 2D identification of the intrinsic PA operation modes is performed first at the current source reference planes. For intrinsic modes defined without lossy parasitics, most of the required source impedance terminations will exhibit a substantial negative resistance after projection to the external reference planes. These terminations can then be implemented by active harmonic injection at the input. It is verified experimentally for a 15 W GaN HEMT class AB mode that using the second harmonic injection synthesized by the embedding device model at the input, yields an improved drain efficiency of up to 5% in agreement with the simulation. An asymmetric Doherty amplifier was built using two 15Wpeak power packaged GaN transistors for the demonstration of the proposed method. 71% drain efficiency at the peak power of 41.8 dBm and 62.7% at the second peak of 32.8 dBm (9 dB back-off) were observed. Above 50% drain efficiency was maintained over the 11 dB output power range. 51.86% average drain efficiency was observed after linearization maintaining -51.46 dBc adjacent channel power ratio excited by 10 MHz bandwidth long term evolution signals with 9.96 dB peak to average power ratio. A novel procedure was introduced for designing Doherty amplifiers using the model based nonlinear-embedding technique. First, the Doherty intrinsic load matching network is designed at the transistor current-source reference-plane with the main and auxiliary devices interconnected. Identical devices with different biasing are used for realizing an asymmetric Doherty implementation with 9 dB back-off. An even-number multi-section impedance transformers and a reduced drain voltage of the main amplifier are used. A closed form analysis of the asymmetric Doherty load network is provided.
Patrick Roblin (Advisor)
Roberto Rojas-Teran (Committee Member)
Steven Bibyk (Committee Member)
Christopher Hadad (Committee Member)
146 p.
Electrical Engineering
De-embedding; Doherty; embedding; harmonic load-pull; large-signal model; load modulation; load synthesis; nonlinear; power amplifier

Recommended Citations

Citations

  • Jang, H. (2014). NONLINEAR EMBEDDING FOR HIGH EFFICIENCY RF POWER AMPLIFIER DESIGN AND APPLICATION TO GENERALIZED ASYMMETRIC DOHERTY AMPLIFIERS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406269587

    APA Style (7th edition)

  • Jang, Haedong. NONLINEAR EMBEDDING FOR HIGH EFFICIENCY RF POWER AMPLIFIER DESIGN AND APPLICATION TO GENERALIZED ASYMMETRIC DOHERTY AMPLIFIERS. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1406269587.

    MLA Style (8th edition)

  • Jang, Haedong. "NONLINEAR EMBEDDING FOR HIGH EFFICIENCY RF POWER AMPLIFIER DESIGN AND APPLICATION TO GENERALIZED ASYMMETRIC DOHERTY AMPLIFIERS." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406269587

    Chicago Manual of Style (17th edition)

osu1406269587
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This open access ETD is published by The Ohio State University and OhioLINK.