A 1-3-GHz Digitally Controlled Dual-RF Input Power-Amplifier Design Based on a Doherty-Outphasing Continuum Analysis
Journal article, 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

Author

[Person 4263e52c-fd50-4591-bbf0-8132eeb07bd7 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

[Person 8ecae0e4-e1d8-4b14-ace3-640971a83494 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

[Person c9df491e-b7c9-451b-ac12-2e241c840d44 not found]

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

[Person 1d29e403-217c-4326-931b-f1608463f4b0 not found]

[Person 73654e57-e620-4add-a8b6-dfbd5220a294 not found]

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 61 10 3743-3752

Areas of Advance

Information and Communication Technology

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TMTT.2013.2280562

More information

Created

10/7/2017