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Dr Jonathan Lees

Dr Jonathan Lees

Head of Department, Electrical & Electronic Engineering
Reader

School of Engineering

Email
leesj2@cardiff.ac.uk
Telephone
+44 (0)29 2087 4318
Campuses
E/3.11
Users
Available for postgraduate supervision

Overview

My key research areas are linear-efficient PA design and microwave characterisation with a specific interest in the design and optimisation of High-Efficiency Power Amplifiers. Significant achievements include the first published GaN Doherty amplifier, and more recently, activities considering the development of novel high-power, broad-band time-domain measurement and load-pull techniques that directly address the current and future needs of modern communication systems.

My most recent research activities include developement of compound semiconductors devices and circuits for high-frequency electronics, mm-wave characterisation, investigating RF properties of materials, microwave heating and disruption and application of microwave engineering to healthcare and diagnostics.

Biography

I began my career in 1998 developing optical and GPS-based positional tracking solutions with QinetiQ, U.K. and became a chartered Engineer in 1999. I obtained my MSc. and PhD. degrees from Cardiff University in 2002 and 2006 respectively and joined the Centre for High Frequency Engineering (CHFE) as a Research Associate in June 2005. I became a Lecturer in 2011 and then in 2016, a Senior Lecturer in Non-Linear Microwave Characterisation. Between 2009 and 2010, I was seconded to Mesuro as a Senior Hardware Engineer.

My current  academic roles include Head of Department for Electrical and Electronic Engineering, as well as Year-4 MEng Tutor. Previous roles include  Director of Taught Postgraduate programmes for Engineering, Year-1 Tutor for Integrated and Electrical and Electronic Engineering and Director for the Wireless and Microwave Communications Engineering MSc and its variants.

My research focus is developing non-linear microwave measurement and characterisation capabilities, high-performance microwave amplifiers, as well as the study of device non-linearity and linearization using modulated time-domain and envelope domain techniques. My work in this area culminated in the first published GaN Doherty amplifier, and more recent activities consider the development of novel high-power, broad-band time-domain measurement and load-pull techniques as well as dynamic supply modulation techniques in achieving high efficiency and high linearity in microwave power amplifiers. Over recent years I have applied my microwave expertise to medical and other applications, including the design of highly integrated microwave power amplifiers for diagnostic applications, and the generation and use of high power pulsed microwave energy for the detection of clostridium difficile.

I currently supervise / co-supervising over 10 PhD students in Microwave Engineering and related fields. I represented Cardiff University (founder member) in the European EUREKA OperaNET-2 programme driving down power consumption in mobile communications system networks.

Honours and awards

In June 2018 I was awarded the Cardiff University Business Innovation award for work with a local company developing low-power autonomous load-cells.

EEE Teacher of the Year award – EN3082/782 – 2016/17

Publications

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2015

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2003

Teaching

I became a Fellow of the Higher Education Academy in 2014.

My teaching currently spans all years of Electrical and Electronic Engineering undergraduate and taught postgraduate programmes, as well as various pre-sessional and outreach programmes.

I lead four MSc / MEng modules; Research Project, HF-RF Engineering, Advanced CAD, Fabrication and Test, RF Design and CAD, as well as one first year module; Analogue Communications.

Other current and recent roles include:

Year 4 Tutor – MEng Integrated and Electronic Engineering (current)

Year 1 Tutor – Integrated and Electronic Engineering

MSc Tutor - Wireless and Microwave Communications Engineering (including variants – MRes & 2-year schemes)

MSc Tutor – Communications Technology & Entrepreneurship

MSc Tutor – Compound Semiconductor Electronics

I belong to the centre for high-frequency engineering (CHFE), a research group that has traditionally, and sucessfully focussed its research activities on commercial microwave communication systems, applications of compound semiconductors and more recently, resonant structures for sensing and disruption.

Compound semiconductor electronics - The CHFE is currently leading a number of groundbreaking research projects; an EPSRC funded consortium, involving numerous academic partners, developing high-efficiency, high-bandwidth envelope tracking (ET) RF modules for 5G communications systems, that require the close integration of RF and baseband electronics, using the same device technology ideally on the same GaN-on-silicon substrate. The CHFE also leads a major RF-GaN Supply chain project, GaNforCS, involving 10 industrial partners, transferring reseacrh understanding and know-how into industrial processes for volume production, enabling a UK source of RF-GaN devices for communications, security and healthcare applications.

Solid-state microwave heating and disruption - Cardiff University is a member of the radio frequency energy alliance (RFEA), a European consortium promiting the use of solid-state semiconductor technology for mass-market domestic and industrial heating and disruption applications. Current research explores the idea of multiple-feed solid state heating for microwave assisted curing of composites. There are significant benefits linked to the precise control achievable through solid-state microwave heating compared to the traditional, magnetron based and autoclave approaches.

Microwave assisted systems for healthcare - I have been involved with a number of collaborative research projects with the Schools of Dentistry and pharmacy, looking at ways in which we can use an applied microwave electrical field to a) inhibit the formation and growth of anti-microbial resistant biofilms, and b) the disruption of bacterial cell and spore to expose DNA for enhance rapid detection of antimicrobal resistant desiese. One example that is particulary important in terms of its potential impact, is the The Phoenix project is a Cardiff university gateway project in which the university is working with colleagues in Namibia to address some of the major healthcare problems which the country is currently facing. Of particular concern is the spread of antibiotic resistant tuberculosis with over 200,000 active cases at any one time. Treating the disease is particularly challenging as the current diagnostic methods lack sensitivity and speed and require access to infrastructure such as mains electricity. Given that many of the affected individuals live a nomadic life style, in areas remote from major centres of population, timely access  to healthcare is a challenge.

In joint collaboration, the schools of Engineering and Pharmacy are developing a microwave based real-time point of care assay capable of detecting a range of pathogens, including tuberculosis, within a time frame which allows the patient to be diagnosed and appropriately treated during the same healthcare visit. To develop this capability, we aim to address three linked technical challenges;

  1. The development of a simple and robust energy capture system capable of supporting the operation of the assay in areas of Namibia remote from mains power
  2. A low-power microwave disruption system capable of mediating the release of target DNA from a range of clinical samples.
  3. A simple to read, pathogen-specific lateral flow assay

The microwave disruption platform is based on solid-state microwave electronics and small single-mode resonant microwave cavities that focus a pulsed electrical field within a sample containing planktonic bacteria or bacterial spore, in order to lyse cells and liberate target DNA.

The use of solid-state microwave electronics is key to the success of this project, and importantly allows low-voltage battery and renewable energy solutions to be considered, suitble for remote field deployment.

The microwave hardware is continually being optimised, and recent research conducted at Cardiff School of Engineering has demonstrated that it is possible to reduce the size, weight and importantly the required microwave power levels dramatically, such that the power requirement for DNA extraction is now similar to that delivered by a mobile phone handset.

These advances, coupled with the high-efficiency microwave amplifier design techniques pioneered at Cardiff University, now provide the real possibility that the diagnostic tool envisaged could be powered locally using solar or simple hand-crank generators.

As part of this ongoing work, and in addition to the microwave elements, we will aim to develop a simple, mobile, electrical energy generation and storage system capable of quickly energising the diagnostic system. We will then look to deploy the combined system to Namibia and in partnership will colleagues from the school of Medicine of the University of Namibia, determine the ability of the system to detect TB in the field.

Research Contracts

TitlePeopleSponsorValueDuration
GaNfoCS – Gallium Nitride for Communications and SecurityLees J, Elgaid K, Tasker PWEFO-ERDF£2.8M01/01/2020 - 30/08/2022
Non-linear (large signal) millimetre-wave devices, circuits and systems on-water characterisation facilityPJ Tasker, R Quaglia, K Elgaid, J Bell, S Cripps, J Benedikt, J LeesEPSRC£1.5M01/10/2018 - 01/09/2019
mm-wave power amplifiers for active antenna arraysQuaglia R, Lees J, Cripps CHuawei£73k01/11/2018 - 01/11/2019
Development of power management and storage and efficient detection and wireless transmission for SHM systemsFeatherston C, Lees J, Pullin READS£200k01/10/2011 - 30/09/2014
SENsors to Inform and Enable wireless NeTworksFeatherston C, Pullin R, Lees J, Holford KTSB via HW Communications£143k01/01/2014 - 31/12/2016
MontaguFeatherston C, Pullin R, Lees J, Holford KTSB - Innovate UK£114k01/05/2015 - 31/10/2017
Self-powered autonomous device for wireless structural health monitoring (SANDWICH)Featherston C, Pullin R, Lees J, Holford, KTSB£40k01/05/2013 - 31/10/2016
RF Power Amplifiers based upon Silicon-Germanium (SiGe) BiCMOS technology (studentship)Tasker P, Lees JSiGe Semiconductor (Europe) Ltd£30k01/10/2010 - 31/03/2014
Baseband linearisation schemes for high efficiency power amplifiersTasker P, Lees JInfinion Technologies North America Corp£35k01/01/2015 - 31/12/2017
High performance buffers for RF GaN electronicsTasker P, Lees JEPSRC£250k01/10/2016 - 31/03/2020
Multi-Mode DI - ADCBelcher R, Lees J, Naylon ASELEX Galileo£100k01/10/2011 - 31/01/2013
High-efficiency device characterisation for OperaNETBenedikt J, Lees JFreescale Semiconductor5000001/10/2008 - 30/09/2011
Upgrading the small equipment base for early career researchers in the Engineering and Physical SciencesHolford K, Whatling G, Lees J, Anderson P I, Brousseau E, Cipcigan L M, Pullin R, Bigot S, Theobald P, Simpson R N, Kawashita L F, Clarke AEPSRC49832601/11/2012 - 31/03/2013
BST Capacitor characterisationLees JANALOG DEVICES350010/12/2012 - 09/01/2013
Efficient Composite Curing by Intelligent Microwave ProcessingLees J, Evans SL, Porch A, Eaton MEPSRC Centre for Innovative Manufacturing in Composites - CIMComp, via Nottingham4906901/05/2015 - 31/10/2015
To develop autonomous load cells through the development of power management electronics, wireless communication and energy harvesting technologies for a wide range of monitoring applicationsLees J, Pullin R, Featherston C, Eaton MKTP and Flintec12257001/10/2013 - 30/09/2015
Development and Realisation of Novel, Broadband, High-Efficiency Power Amplifiers (studentship)Lees J, Tasker PFreescale Semiconductor France SAS5000001/01/2012 - 31/12/2014
High Performance power amplifiers for phased array radar and point to point communication applicationsLees J, Tasker PM/A COM Technology Solutions (UK) Ltd4500001/10/2011 - 30/09/2014
Integrating High-Performance Power Amplifier with Miniturized Wideband Antenna for Highly-Efficient Future Communication DevicesLees J, Tasker P, Cripps SSer Cymru NRN AEM Swansea5935001/10/2014 - 30/09/2017
Development and realisation of novel broadband high efficiency power amplifiersTasker P, Lees JFreescale Semiconductors France SAS5000001/10/2012 - 30/09/2015
GaN electronics: RF reliability and detradation mechanismsTasker P, Lees JEPSRC22239201/01/2013 - 31/12/2015
Integration of RF Circuits with High Speed GaN Switching on Silicon SubstratesTasker P, Lees J, Benedikt JEPSRC83507401/04/2016 - 31/03/2019
Characterisation and comparison of packaged GaN devisesTasker PJ, Benedikt J, Lees J,Cree Inc1693101/05/2008 - 01/09/2008
Dynamic Characterisation and modelling of RF GaN HEMTsTasker PJ, Lees JSer Cymru NRN AEM Swansea8130001/10/2014 - 30/09/2017
Develop an ultra rapid diagnostic system capable of detecting the presence of C. difficile in a clinincal sample at the bedside in under 10 minutesBaillie L(PHRMY), Lees J, Porch ACardiff Partnership Fund1202201/09/2014 - 31/08/2015
Clean and Green Microwave heating using solid state physicsCripps, S, Porch A, Lees JNXP Semiconductors Netherlands B V3000001/10/2011 - 30/09/2014

Supervision

Current Research Interests

I am interested in supervising PhD students in the areas of

  • High efficiency Power Amplifier Design
  • mm-wave power amplifier design
  • Microwave and mm-wave circuit design techniques
  • Medical applications of microwave engineering
  • Microwave and mm-wave characterisation

Current Students

TitleStudentStatusDegree
Device Level Characterisation of Out-phasing Power AmplifiersAleksander BoguszCurrentPhD
Integrated Envelope Tracking Power Amplifiers for 5G communicationsAlexander AltCurrentPhD
Measurement-Based Non-linear Modelling for Active DevicesZack CostelloCurrentPhD
Integrating High-Performance Power Amplifiers with 

Miniaturised Wideband Antennas for Highly-Efficient Future Communications Devices

Elango Nagasundaram CurrentPhD

Past projects

Supervised Students

TitleStudentStatusDegree
A Modulated Active Load Pull Characterisation System for 5GSattam AlsahaliGraduatePhD
Investigation of Novel Measurement Techniques for Microwave DevicesALDOUMANI AnoorGraduatePhD
Solid-State Microwave heating For Biomedical ApplicationsIMTIAZ AzeemGraduatePhD
Re-configure high efficiency power amplifiers.SHEPPHARD Daniel JohnGraduatePhD
Biomedical Applications of Microwave EngineeringSHKAL Fatma AhmedGraduatePhD
Novel Power Amplifier Design Using Non-Linear Microwave Charcterisation and Measurement TechniquesOGBOI Friday LawrenceGraduatePhD
Baseband Linearisation Schemes for High Efficiency Power AmplifiersWANG GuefengGraduatePhD
Use of microwave technologies in the detection of pathogenic bacteriaHAMZAH Hayder Miri HamzahGraduatePhD
Characterisation of Powders Using Microwave Cavity PerturbationCUENCA Jerome AlexanderGraduatePhD
Development of an efficient energy storage and power management for autonomous aircraft structural health monitoring systemTHANGARAJ KarthikGraduatePhD
Power amplifier design for microwave heating applicationsCHAUDHRY KauserGraduatePhD
MICROWAVE CHARACTERISATION OF AMMINES FOR ENERGY STORAGE APPLICATIONS.BARTER MichaelGraduatePhD
RADIATION-BASED TECHNOLOGY TO ENHANCED MICROBICIDAL ACTIVITY OF BIOCIDESPASCOE MichaelGraduatePhD
High performance power amplifiers for phased array radar and point to point communication application.KOH MinghaoGraduatePhD
High Resolution Electric Field Probes With Applications In High Efficiency RF Power Amplifier DesignDEHGHAN NeloGraduatePhD
USE OF NOVEL SENSING TECHNIQUES IN NEAR NETT SHAPE MANUFACTURING.CLARK Nicholas SebastianGraduatePhD
RF techniques applied to additive manufacturingPARKER NyleGraduatePhD
DEVICE CHARACTERISATION FOR WIDEBAND, HIGH EFFICIENCY POWER AMPLIFIERSWILSON Richard JasonGraduatePhD
MICROWAVE PROCESSING IN ADDITIVE MANUFACTURING.HEFFORD Samuel JohnGraduatePhD
ELECTROMAGNETIC PROPERTIES OF SEMICONDUCTING METAL OXIDES UNDER EXTERNAL STIMULATION.PARTRIDGE Samuel LeeGraduatePhD
Sensors to Inform & Enable Wireless NetworksGRIGG StephenGraduatePhD
DOHERTY AMPLIFIER WITH AID OF AD-HOC OPTIMIZATION FOR SDR APPLICATIONS.KAMARUDIN Syalwani BintiGraduatePhD
The Auxiliary Envelope Tracking RF Power AmplifiersYUSOFF ZubaidaGraduatePhD
DEVELOPMENT OF A BROADBAND AND EFFICIENT LINEAR TRANSMITTERA MOKHTI Zulhazmi BinGraduatePhD