Transformer-based Broadband mm-Wave InP PA across 42-62 GHz with enhanced linearity and second harmonic engineering

Zheng Liu, Tushar Sharma, Chandrakanth R. Chappidi, Suresh Venkatesh, Kaushik Sengupta

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Scopus citations


InP HBTs with fmax crossing 600 GHz can enable high-efficiency and broadband power amplifiers at mm-Wave frequencies for applications in communication, sensing and imaging. InP PA design has traditionally relied on a classical microwave approach with transmission-line based impedance matching and power combining. On the other hand, silicon-based PAs, at RF and mm-Wave frequencies, have evolved tremendously over the last two decades, employing passive transformer and inductor-based impedance matching and power combining, allowing such topologies to be compact and efficient. In this paper, we present for the first time InP topologies incorporating the following 1) efficient and compact transformer-based power combining, 2) linearity enhancement technique to reduce AM-PM distortion and 3) second harmonic load pull impedance exploiting the common mode impedance synthesis at the transformer. This work presents a transformer-based push-pull InP power amplifier in 0.25 μm technology across 42-62 GHz demonstrating a peak PAE of 39.5% and peak Psat of 20.6 dBm. The PA supports QPSK signals with 4 GHz bandwidth (data rate of 8 Gb/s) at 55 GHz with superior linearity and adjacent channel leakage ratio (ACLR) of -31.84 dBc. To the best of the authors' knowledge, this work presents one of the highest efficiency and highest linearity mmWave PAs in InP technology.

Original languageEnglish (US)
Title of host publicationIMS 2020 - 2020 IEEE/MTT-S International Microwave Symposium
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)9781728168159
StatePublished - Aug 2020
Event2020 IEEE/MTT-S International Microwave Symposium, IMS 2020 - Virtual, Los Angeles, United States
Duration: Aug 4 2020Aug 6 2020

Publication series

NameIEEE MTT-S International Microwave Symposium Digest
ISSN (Print)0149-645X


Conference2020 IEEE/MTT-S International Microwave Symposium, IMS 2020
Country/TerritoryUnited States
CityVirtual, Los Angeles

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


  • 5G
  • Broadband
  • High efficiency
  • InP
  • Linearity enhancement
  • Millimeter-Wave
  • Power amplifier
  • Push-pull
  • Transformer


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