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Dr Jonathan Lees

Dr Jonathan Lees

Lecturer

School of Engineering

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

Overview

I began my career in 1998 developing optical and GPS-based positional tracking solutions with QinetiQ, U.K.  I became a chartered Engineer in 1999 and obtained my MSc. and PhD. degrees from Cardiff University in 2002 and 2006 respectively. I am currently employed as a Senior Lecturer in Non-Linear Microwave Characterisation within Cardiff University’s Centre for High Frequency Engineering (CHFE) where 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. My work in this area includes 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 recent research activities include investigation into RF properties of materials, microwave heating and disruption and application of microwave engineering to healthcare diagnostics.

Biography

I joined Cardiff University as a Research Associate in June 2005, became a Lecturer in 2011 and Senior Lecturer in 2016. From 2009 to 2010, I was seconded to Mesuro as a Senior Hardware Engineer. I received his PhD in 2006 from Cardiff University.

My academic roles have included Director of Taught Postgraduate programmes, Year-1 Tutor for Integrated and Electrical and Electronic Engineering and Director for the MSc in Wireless and Microwave Communications Engineering. My current 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. I am currently a Lecturer in Non-Linear Microwave Engineering, and 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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Teaching

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 modules: HF-RF Engineering, MSc Research Study,  Software Tools and Simulation, Advanced CAD, Fabrication and Test, as well as one first year module: Electronics Laboratory. I also teach on three other modules: Electrical and Electronic Engineering 4, Analogue Electronics and RF Cad and Design.

Other current and recent roles include:

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 in commercial microwave communication systems and more recently, applications of resonant sensors and applicators for sensing and disruption. The research opportunities that I am now focussing on exist in the key areas of compound semiconductor electronics, solid-state microwave heating and microwave assisted systems for healthcare.

Solid-state microwave heating and disruption– Cardiff University is a member of the radio frequency energy alliance (RFEA), a new European consortium promiting the use of solid-state semiconductor technology for mass-market domestic and industrial heating and disruption applications.  I currently supervise a self-funded PhD student looking into multiple-feed microave heating structures, which is highly aligned with this space. A number of patent disclosures have recently been initiated and the flexibility provided by this research leave would allow me to accelerate this work. 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 am currently 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.

Compound semiconductor electronics- The CHFE is currently leading an EPSRC funded consortium, involving numerous academic partners, developing high-efficiency, high-bandwidth envelope tracking (ET) RF modules for 5G communications systems. These modules rely on the close integration of RF and baseband electronics, using the same device technology ideally on the same GaN-on-silicon substrate. To achieve impact in this area, this work needs to be accelerated.

In addition, there are a number of novel RF-to-DC rectifier circuit ideas that are emerging from Cardiff activities in the baseband modulator space that, fall outside of the defined project scope. These potentially offer significant advantage over conventional techniques, and I believe that this area needs to be urgently investigated to exploite publication and possible research grant opportunity.

Research Contracts

TitlePeopleSponsorValueDuration
Development of power management and storage and efficient detection and wireless transmission for SHM systemsFeatherston C, Lees J, Pullin READS1998001/10/2011 - 30/09/2014
SENsors to Inform and Enable wireless NeTworksFeatherston C, Pullin R, Lees J, Holford KTSB via HW Communications14396301/01/2014 - 31/12/2016
MontaguFeatherston C, Pullin R, Lees J, Holford KTSB - Innovate UK11437801/05/2015 - 31/10/2017
Self-powered autonomous device for wireless structural health monitoring (SANDWICH)Featherston C, Pullin R, Lees J, Holford, KTSB3981601/05/2013 - 31/10/2016
RF Power Amplifiers based upon Silicon-Germanium (SiGe) BiCMOS technology (studentship)Tasker P, Lees JSiGe Semiconductor (Europe) Ltd3000001/10/2010 - 31/03/2014
Baseband linearisation schemes for high efficiency power amplifiersTasker P, Lees JInfinion Technologies North America Corp3500001/01/2015 - 31/12/2017
High performance buffers for RF GaN electronicsTasker P, Lees JEPSRC24999901/10/2016 - 31/03/2020
Multi-Mode DI - ADCBelcher R, Lees J, Naylon ASELEX Galileo10000001/10/2011 - 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

Supervised Students

TitleStudentStatusDegree
Device level characterisation of out-phasing amplifiersBOGUSZ AleksanderCurrentPhD
Investigation of Novel Measurement Techniques for Microwave DevicesALDOUMANI AnoorCurrentPhD
Solid-State Microwave heating For Biomedical ApplicationsIMTIAZ AzeemGraduatePhD
Re-configure high efficiency power amplifiers.SHEPPHARD Daniel JohnCurrentPhD
INTEGRATING HIGH-PERFORMANCE POWER AMPLIFIERS WITH MINIATURIZED WIDEBAND ANTENNAS FOR HIGHLY-EFFICIENT FUTURE COMMUNICATION DEVICES.NAGASUNDARAM ElangoCurrentPhD
Biomedical Applications of Microwave EngineeringSHKAL Fatma AhmedCurrentPhD
NOVEL POWER AMPLIFIER DESIGN USING NON-LINEAR MICROWAVER CHARACTERISATION AND MEASUREMENT TECHNIQUESOGBOI Friday LawrenceGraduatePhD
BASEBAND LINEARISATION SCHEMES FOR HIGH EFFICIENCY POWER AMPLIFIERS.WANG GuefengCurrentPhD
Use of microwave technologies in the detection of pathogenic bacteriaHAMZAH Hayder Miri HamzahCurrentPhD
Characterisation of Powerders Using Microwave Cavity PerturbationCUENCA Jerome AlexanderGraduatePhD
Development of an efficient energy storage and power management for autonomous aircraft structural health monitoring systemTHANGARAJ KarthikThesis SubmittedPhD
Power amplifier design for microwave heating applicationsCHAUDHRY KauserCurrentPhD
MICROWAVE CHARACTERISATION OF AMMINES FOR ENERGY STORAGE APPLICATIONS.BARTER MichaelCurrentPhD
RADIATION-BASED TECHNOLOGY TO ENHANCED MICROBICIDAL ACTIVITY OF BIOCIDESPASCOE MichaelCurrentPhD
High performance power amplifiers for phased array radar and point to point communication application.KOH MinghaoThesis SubmittedPhD
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 SebastianCurrentPhD
RF techniques applied to additive manufacturingPARKER NyleCurrentPhD
DEVICE CHARACTERISATION FOR WIDEBAND, HIGH EFFICIENCY POWER AMPLIFIERSWILSON Richard JasonCurrentPhD
MICROWAVE PROCESSING IN ADDITIVE MANUFACTURING.HEFFORD Samuel JohnCurrentPhD
ELECTROMAGNETIC PROPERTIES OF SEMICONDUCTING METAL OXIDES UNDER EXTERNAL STIMULATION.PARTRIDGE Samuel LeeCurrentPhD
Sensors to Inform & Enable Wireless NetworksGRIGG StephenCurrentPhD
DOHERTY AMPLIFIER WITH AID OF AD-HOC OPTIMIZATION FOR SDR APPLICATIONS.KAMARUDIN Syalwani BintiCurrentPhD
The Auxiliary Envelope Tracking RF Power AmplifiersYUSOFF ZubaidaGraduatePhD
DEVELOPMENT OF A BROADBAND AND EFFICIENT LINEAR TRANSMITTERA MOKHTI Zulhazmi BinCurrentPhD