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Linearization of BJTs with logarithmic predistortion

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Original languageEnglish
Title of host publication2019 IEEE Radio and Wireless Symposium, RWS 2019
ISBN (Electronic)9781538659441
Publication statusPublished - 14 May 2019
Publication typeA4 Article in a conference publication
EventIEEE Radio and Wireless Symposium - Orlando, United States
Duration: 20 Jan 201923 Jan 2019

Publication series

NameIEEE Radio and Wireless Symposium, RWS
ISSN (Print)2164-2958
ISSN (Electronic)2164-2974


ConferenceIEEE Radio and Wireless Symposium
CountryUnited States


This paper proposes a novel linearization technique for bipolar junction transistors (BJT) and their derivatives, e.g., heterojunction BJTs. Since the non-linearity of BJTs is exponential by nature, analog predistortion caused by a logarithmic amplifier should linearize the response completely, in theory. This paper reports that, in practice, cascading a logarithmic amplifier in front of a simple one-transistor BJT amplifier boosted its output third-order inter-modulation intercept point (OIP3) by 10 dB. The proposed linearization scheme is extremely simple and it is inherently broadbanded. To the best of our knowledge, this idea has not been reported previously.


  • Analogue predistortion, Linearization techniques, Log amplifier, Logarithmic amplifier, Nonlinearity, Power amplifer

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