A linearity enhancement technique for envelope tracked cascode power amplifiers

Sumit Bhardwaj, Soroush Moallemi, Jennifer Kitchen

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

1 Scopus citations

Abstract

This work presents a linearity enhancement technique for envelope tracked linear power amplifiers (ET-PAs). To enhance linearity, the proposed technique dynamically biases the cascode device with respect to the RF input signal's envelope in a cascoded ET -PA architecture. The effect of supply voltage (VDD) variation on the PA's drain impedance due to the envelope tracking operation is characterized in this work. Furthermore, the impact of variable supply on the AM-PM and IMD3 linearity is analyzed. A class-AB PA using the presented technique is designed and simulated in a CMOS TSMC 65nm process with 2.2V nominal supply voltage. The designed PA demonstrates a saturated output power (Psat) of+19.2dBm with a power gain (Gp) of 16dB for a frequency range of 2.4-2.6GHz, while maintaining maximum power-added efficiency (PAE) of 55%. The supply of this PA is modulated to analyze the effects of envelope tracking on PA performance. With the presented technique, the PA's AM-PM variation is within 1°, IMD3 improves by 4dB, and the PA's drain impedance variation reduces by 37.5% when compared to the ET-PA without the dynamic bias for linearity enhancement.

Original languageEnglish (US)
Title of host publicationProceedings of the 2020 IEEE Texas Symposium on Wireless and Microwave Circuits and Systems
Subtitle of host publicationMaking Waves in Texas, WMCS 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728161921
DOIs
StatePublished - May 2020
Externally publishedYes
Event2020 IEEE Texas Symposium on Wireless and Microwave Circuits and Systems, WMCS 2020 - Virtual, Online, United States
Duration: May 26 2020May 28 2020

Publication series

NameProceedings of the 2020 IEEE Texas Symposium on Wireless and Microwave Circuits and Systems: Making Waves in Texas, WMCS 2020

Conference

Conference2020 IEEE Texas Symposium on Wireless and Microwave Circuits and Systems, WMCS 2020
Country/TerritoryUnited States
CityVirtual, Online
Period5/26/205/28/20

Keywords

  • CMOS
  • Efficiency Enhancement
  • Envelope Tracking
  • Load pull
  • Radio Frequency
  • Supply Modulator

ASJC Scopus subject areas

  • Artificial Intelligence
  • Computer Networks and Communications
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering
  • Instrumentation

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