A 1-3-GHz Digitally Controlled Dual-RF Input Power-Amplifier Design Based on a Doherty-Outphasing Continuum Analysis
Artikel i vetenskaplig tidskrift, 2013

This paper presents a linear multi-harmonic analysis method to evaluate the performance of digitally controlled dual RF-input power amplifiers (PAs). The method enables, due to its low computational cost, optimization of PA efficiency and bandwidth in a complex design space involving two independent inputs. Under the idealized assumption of short-circuited higher harmonics, the analysis is used to prove the existence of a Doherty-outphasing continuum, featuring high average efficiency over 100% fractional bandwidth. With this result as a foundation, a combiner incorporating microwave transistor parasitics is analyzed without assuming short-circuited higher harmonics, showing that high average efficiencies are also achievable under more realistic conditions. A PA is straightforwardly designed from these calculation results using two 15-W GaN HEMTs. The simulated layout-ready (large-signal transistor model) PA average drain efficiency exceeds 50% over 1.1-3.7 GHz for a 6.7-dB peak-to-average power-ratio WCDMA signal. The measured PA has a maximum output power of 44 +/- 0.9 dBm and a 6-dB output power back-off (OPBO) power-added efficiency (PAE) of 45% over 1-3 GHz. After applying digital pre-distortion, excellent linearity is demonstrated when transmitting the WCDMA signal, resulting in an adjacent channel leakage power ratio lower than -57 dBc with corresponding average PAE of 50% and 40% at 1.2 and 2.3 GHz, respectively. This is, to the authors' knowledge, the most wideband OPBO efficiency enhanced PA reported to date, proving the effectiveness of employing linear multi-harmonic analysis in dual-input PA design.

Doherty

outphasing

gallium-nitride (GaN)

power amplifiers (PAs)

Chireix

energy efficiency

Författare

Christer Andersson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Mikrovågselektronik

David Gustafsson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Mikrovågselektronik

Jessica Chani Cahuana

Signaler och system, Kommunikationssystem, informationsteori och antenner, Kommunikationssystem

Richard Hellberg

Christian Fager

Chalmers, Mikroteknologi och nanovetenskap (MC2), Mikrovågselektronik

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 61 3743-3752

Styrkeområden

Informations- och kommunikationsteknik

Ämneskategorier

Annan elektroteknik och elektronik

DOI

10.1109/TMTT.2013.2280562