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Waveform engineering at gate node of class-j power amplifiers

Alizadeh, A ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1109/TMTT.2017.2651814
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2017
  4. Abstract:
  5. In this paper, the class-J mode of operation is investigated when sinusoidal, half-sinusoidal (HS), triangle, pulse, and reduced conduction angle voltage waveforms are shaped at the gate node of the transistor. Output power, maximum power-added efficiency (PAE), large signal gain (LSG), and load-pull contours are presented and compared for each input signal. It is shown that PAE of a class-J power amplifier (PA) is improved when an HS voltage is realized at the gate node of the transistor. This enhancement can also be observed for a pulse input with 20% duty cycle, however, at the expense of reduced output power and LSG. A proof-of-concept, two-stage class-J PA is designed and fabricated in a 0.25- $mu ext{m}$ AlGaAs-InGaAs pHEMT technology. The prototype PA is based on an HS gate voltage for the second-stage transistor, which operates in class-J mode. The driver stage also works in class-J mode to provide an HS voltage at its drain node, and the interstage matching network is designed to convey this waveform to gate of the second-stage transistor. Chip dimensions are $1.99 imes1.24$ mm2, and 26.6-27.2-dBm output power with ≥50% PAE is achieved over the 0.92-1.4-GHz bandwidth. © 1963-2012 IEEE
  6. Keywords:
  7. Class-J ; Harmonic-injection PAs ; Harmonically tuned power amplifiers (PAs) ; Monolithic microwave integrated circuit ; PAs ; pHEMT ; Aluminum gallium arsenide ; Amplifiers (electronic) ; Transistors ; Chip dimensions ; Conduction angle ; Matching networks ; Mode of operations ; PHEMT technology ; Proof of concept ; Voltage waveforms ; Waveform engineerings ; Power amplifiers
  8. Source: IEEE Transactions on Microwave Theory and Techniques ; Volume 65, Issue 7 , 2017 , Pages 2409-2417 ; 00189480 (ISSN)
  9. URL: https://ieeexplore.ieee.org/document/7837711