Preserving Polar Modulated Class-E Power Amplifier Linearity under Load Mismatch

Awani Khodkumbhe*, Maikel Huiskamp, Ali Ghahremani, Bram Nauta, Anne J. Annema

*Corresponding author for this work

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

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Power amplifiers (PAs) need digital predistortion (DPD) linearization to handle high-order complex modulation schemes in next-generation communication systems. While load variation is inevitable, DPD is generally designed considering only the nominal load impedance for PAs. This paper presents a polar class-E PA with an on-chip waveform characterizer enabling adaptive digital predistortion (ADPD) to preserve the linearity of the PA under load mismatch. The presented ADPD corrects both AM/AM and AM/PM distortions, which are prominent in the demonstrated PA, while simultaneously correcting for slow memory effects without the need for complex memory DPD algorithms. Load-pull measurements demonstrate that target error vector magnitude (EVM) and adjacent channel power ratio (ACPR) can be maintained in a significantly larger area on the Smith chart going from 50 Ω optimized static DPD to our ADPD for a 2 GHz 1024 QAM signal with 1 MSym/s symbol rate.

Original languageEnglish
Title of host publication2020 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)
Place of PublicationLos Angeles, USA
Number of pages4
ISBN (Electronic)978-1-7281-6809-8
ISBN (Print)978-1-7281-6810-4
Publication statusPublished - 6 Aug 2020


  • CMOS integrated circuits
  • Adaptive control
  • Antennas
  • Distortion
  • Impedance
  • Linearity
  • Power amplifiers
  • Predistortion
  • Quadrature amplitude modulation

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