A Study on Highly Efficient Dual-Input Power Amplifiers for Large PAPR Signals

Atsushi YAMAOKA  Thomas M. HONE  Yoshimasa EGASHIRA  Keiichi YAMAGUCHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E104-C    No.10    pp.506-515
Publication Date: 2021/10/01
Publicized: 2021/03/23
Online ISSN: 1745-1353
DOI: 10.1587/transele.2021MMI0004
Type of Manuscript: Special Section INVITED PAPER (Special Section on Microwave and Millimeter-Wave Technologies)
Category: 
Keyword: 
Doherty amplifier,  outphasing amplifier,  Doherty-outphasing amplifier,  base stations,  multiple-input amplifier,  

Full Text: FreePDF

Summary: 
With the advent of 5G and external pressure to reduce greenhouse gas emissions, wireless transceivers with low power consumption are strongly desired for future cellular systems. At the same time, increased modulation order due to the evolution of cellular systems will force power amplifiers to operate at much larger output power back-off to prevent EVM degradation. This paper begins with an analysis of load modulation and asymmetrical Doherty amplifiers. Measurement results will show an apparent 60% efficiency plateau for modulated signals with a large peak-to-average power ratio (PAPR). To exceed this efficiency limitation, the second part of this paper focuses on a new amplification topology based on the amalgamation between Doherty and outphasing. Measurement results of the proposed Doherty-outphasing power amplifier (DOPA) will confirm the feasibility of the approach with a modulated efficiency greater than 70% measured at 10 dB output power back-off.