High Efficiency Microwave Amplifiers and SiC Varactors Optimized for Dynamic Load Modulation
Doctoral thesis, 2013

The increasing use of mobile networks as the main source of internet connectivity is creating challenges in the infrastructure. Customer demand is a moving target and continuous hardware developments are necessary to supply higher data rates in an environmentally sustainable and cost effective way. This thesis reviews and advances the status of realizing wideband and high efficiency power amplifiers, which will facilitate improvements in network capacity and energy efficiency. Several demonstrator PAs are proposed, analyzed, designed, and characterized: First, resistive loading at higher harmonics in wideband power amplifier design suitable for envelope tracking (ET) is proposed. A 40 dBm decade bandwidth 0.4–4.1 GHz PA is designed, with 10–15 dB gain and 40–62% drain efficiency. Its versatility is demonstrated by digital pre-distortion (DPD) linearized measurements resulting in adjacent channel leakage ratios (ACLR) lower than −46 dBc for various downlink signals (WCDMA, LTE, WiMAX). Second, a theory for class-J microwave frequency dynamic load modulation (DLM) PAs is derived. This connects transistor technology and load network requirements to enable power-scalable and bandwidth conscious designs. A 38 dBm PA is designed at 2.08 GHz, maintaining efficiencies >45% over 8 dB of output power back-off (OPBO) dynamic range. From this pre-study a fully packaged 86-W peak power version at 2.14 GHz is designed. ACLR after DPD is −46 dBc at a drain efficiency of 34%. For DLM PAs there is a need for varactors with large effective tuning range and high breakdown voltage. For this purpose, SiC Schottky diode varactors are developed with an effective tuning range of 6:1 and supporting a 3:1 tuning ratio at 36 V of RF swing. Nonlinear characterization to enable Q-factor extraction in the presence of distortion is proposed and demonstrated by multi-harmonic active source- and load-pull, offering insights to tunable network design. Third, a method to evaluate and optimize dual-RF input PAs, while catering to higher harmonic conditions and transistor parasitics, is proposed. The method is validated by a PA design having a peak power of 44 +/- 0.9 dBm and 6 dB OPBO PAE exceeding 45% over a 1–3 GHz bandwidth. The results in this thesis contribute with a novel device and analysis of high efficiency and wideband PAs, aiding in the design of key components for future energy efficient and high capacity wireless systems.

nonlinear measurements

power amplifiers

load modulation

GaN

SiC

varactors

HEMT

wide bandgap technology

energy efficiency

Kollektorn, MC2, Kemivägen 9, Chalmers University of Technology
Opponent: L. C. N. de Vreede

Author

Christer Andersson

GigaHertz Centre

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Linearization Study of a Highly Efficient CMOS-GaN RF Pulse Width Modulation Based Transmitter

European Microwave Conference,; (2012)p. 136-139

Paper in proceedings

High efficiency RF pulse width modulation with tunable load network class-E PA

2011 IEEE 12th Annual Wireless and Microwave Technology Conference, WAMICON 2011,; (2011)

Paper in proceedings

High-Efficiency RF Pulsewidth Modulation of Class-E Power Amplifiers

IEEE Transactions on Microwave Theory and Techniques,; Vol. 59(2011)p. 2931-2942

Magazine article

Nonlinear Characterization of Varactors for Tunable Networks by Active Source-Pull and Load-Pull

IEEE Transactions on Microwave Theory and Techniques,; Vol. 59(2011)p. 1753-1760

Journal article

Theory and Design of Class-J Power Amplifiers With Dynamic Load Modulation

IEEE Transactions on Microwave Theory and Techniques,; Vol. 60(2012)p. 3778-3786

Journal article

A double stub impedance tuner with SiC diode varactors

Asia Pacific Microwave Conference APMC 2011; Melbourne, VIC; 5 - 8 December 2011,; (2011)p. 267-270

Paper in proceedings

Design and characterization of SiC varactor-based phase shifters

7th European Microwave Integrated Circuits Conference, EuMIC 2012 - Held as Part of 15th European Microwave Week, EuMW 2012; Amsterdam; Netherlands; 29 October 2012 through 30 October 2012,; (2012)p. 897-900

Paper in proceedings

Decade bandwidth high efficiency GaN HEMT power amplifier designed with resistive harmonic loading

IEEE MTT-S International Microwave Symposium Digest,; (2012)

Paper in proceedings

A SiC Varactor With Large Effective Tuning Range for Microwave Power Applications

IEEE Electron Device Letters,; Vol. 32(2011)p. 788-790

Journal article

A Modified Doherty Power Amplifier With Extended Bandwidth and Reconfigurable Efficiency

IEEE Transactions on Microwave Theory and Techniques,; Vol. 61(2013)p. 533-542

Journal article

A novel wideband and reconfigurable high average efficiency power amplifier

IEEE MTT-S International Microwave Symposium Digest,; (2012)

Paper in proceedings

Epitaxial and Layout Optimization of SiC Microwave Power Varactors

Asia-Pacific Microwave Conference Proceedings, APMC (APMC 2011 ;Melbourne, VIC; 5 - 8 December 2011),; (2011)p. 1642-1645

Paper in proceedings

Det ökande användandet av mobila nätverk för internetuppkoppling skapar utmaningar i infrastrukturen. Användarkraven ökar och kontinuerliga hårdvaruförbättringar krävs för att tillgodose högre hastigheter på ett hållbart och kostnadseffektivt sätt. Denna avhandling behandlar och avancerar designen av bredbandiga och energieffektiva effektförstärkare för att förbättra kapacitet och energieffektivitet i mobila nätverk. Flera demonstratorer föreslås, analyseras, designas och karaktäriseras: 1) Resistiv lastning på högre harmoner i bredbandiga förstärkare avsedda för envelop tracking. 2) Förstärkare i klass-J med dynamisk lastmodulering som använder specialutvecklade Schottkydioder i SiC med låga förluster och hög effektiv utstyrning. 3) En metod för att utvärdera och optimera förstärkare med två RF-ingångar, med hänsyn till högre harmoner och transistorparasiter. Resultaten i denna avhandling bidrar med en unik halvledarkomponent samt analys av högeffektiva bredbandiga förstärkare för design av nyckelkomponenter i framtidens energieffektiva trådlösa system med hög kapacitet.

The increasing use of mobile networks as the main source of internet connectivity is creating challenges in the infrastructure. Customer demand is a moving target and continuous hardware developments are necessary to supply higher data rates in an environmentally sustainable and cost effective way. This thesis reviews and advances the status of realizing wideband and high efficiency power amplifiers, which will facilitate improvements in network capacity and energy efficiency. Several demonstrator PAs are proposed, analyzed, designed, and characterized: 1) Resistive loading at higher harmonics in wideband power amplifier design suitable for envelope tracking. 2) Class-J microwave frequency dynamic load modulation amplifiers using specially developed SiC Schottky diode varactors with low loss and large effective tuning range. 3) Evaluation and optimization of dual-RF input PAs, while catering to higher harmonic conditions and transistor parasitics, is proposed. The results in this thesis contribute with a novel device and analysis of high efficiency and wideband PAs, aiding in the design of key components for future energy efficient and high capacity wireless systems.

Areas of Advance

Information and Communication Technology

Driving Forces

Sustainable development

Subject Categories

Telecommunications

Communication Systems

Electrical Engineering, Electronic Engineering, Information Engineering

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

Nanofabrication Laboratory

ISBN

978-91-7385-830-4

Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: 243

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3511

Kollektorn, MC2, Kemivägen 9, Chalmers University of Technology

Opponent: L. C. N. de Vreede

More information

Created

10/7/2017