Push-pull circuits using n-p-n and p-n-p InP-based HBT's for power amplification Article

Sawdai, D, Pavlidis, D. (1999). Push-pull circuits using n-p-n and p-n-p InP-based HBT's for power amplification . IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, 47(8), 1439-1448. 10.1109/22.780392

cited authors

  • Sawdai, D; Pavlidis, D

abstract

  • P-n-p heterojunction bipolar transistors (HBT's) have been combined with n-p-n HBT's in a push-pull amplifier in order to obtain improved linearity characteristics. Simulations of common-collector push-pull amplifiers demonstrate an improvement of 14 dB in second harmonic content at the onset of power saturation under Class-B operation. Further improvement of 14 dB in the third harmonic content is shown by moving to Class-AB operation at an expense of 4% decreased efficiency. A common-emitter push-pull amplifier was fabricated using both n-p-n and p-n-p HBT's with external matching and couplers. Testing of the circuit under Class-AB conditions showed better third-order intermodulation (by approximately 9 dBc) and smaller second harmonic content (by approximately 11 dBc) compared with n-p-n HBT's alone. While the second harmonics were shown to combine destructively in the push-pull amplifier, total cancellation of the second harmonic was prevented by the wide difference in linearity characteristics of the n-p-n and p-n-p HBT's. In addition, the circuit produced over 2 dBm more output power than the n-p-n HBT alone at 1 dB of gain compression.

publication date

  • January 1, 1999

Digital Object Identifier (DOI)

start page

  • 1439

end page

  • 1448

volume

  • 47

issue

  • 8