https://antennas.eecs.qmul.ac.uk/research/active-andreconfigurable-antennas-and-microwave-devices
Bio-electromagnetics for Healthcare and Security
Applications
Bio-electromagnetics examines the interaction between electromagnetic (EM) fields and
biological organisms and tissues. Bioelectromagnetic studies within this group focus on stateof-the-art and novel methods to assess the interactions of EM fields across the spectrum with
biological tissues, and develops means to develop new diagnostic and treatment technologies
to serve today’s and future society. The group also focuses on EM compliance and safety
assessments as well as improving the current standards by shedding further light on the
assessment of EM properties of biological tissues and engaging with national and international
committees and standard bodies to improve the current public guidelines.
The group’s interests include (not exclusive to):
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EMF safety exposure assessments
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Complex modelling of EM exposure and thermal patterns inside living systems
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Assessments of dielectric properties of tissues across the frequency spectrum
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Development of novel and state-of-the-art diagnostic and treatment technologies.
Our research aims to lead in innovation and in the development of more biologically-friendly,
ecologically-sustainable and application-participator technologies and solutions.
Electromagnetic Interaction with Microparticles for Drug Delivery
Systems
Rostyslav Dubrovka, Robert Donnan
The need for a sustained and better controlled drug administration has given rise to the
development of novel drug delivery systems. A controlled drug release mechanism can help in
maintaining drug dosage levels as well as optimise therapeutic effects and reduce side effects.
Microparticles and nano-particles, initially developed as the carriers for vaccine and anticancer
drugs, are now being used in drug delivery systems for drug targeting, improved release profile
and increased efficiency. Therefore, this research involves the development of a remotely
activated drug delivery system wherein electromagnetic interactions with metallic micro and
nano-particles triggers the drug delivery
Schematic of Controlled Drug Delivery Implant consisting of split ring resonators as receivers of
the incident microwave signals. The thermosensitive hydrogel is located near the gap regions of
the resonators and metallic microparticles are embedded inside the hydrogel
The interaction of EM waves with small particles has enabled the development of advanced
technologies like microscopic imaging, optical trapping, thermotherapy, micro and
nanoparticle mediated drug delivery and cell penetration to name a few. However, the
interaction of EM waves with matter at microwave frequencies is understood mostly for
dielectric heating mechanism which occurs due to the electric field component of the EM
radiation at a high frequency. But the microwaves also have a magnetic field component which
also couples with certain metals in sufficiently small size and can generate heat. Thus, heating
effects of EM radiation at the microwave frequencies can be due to dielectric heating, Joule
heating, magnetic loss heating, etc. and the total power loss due to the heating effect of these
EM waves can be obtained as a function of both the components of the electromagnetic field.
Therefore, metallic particles can be used as the agents for increasing temperature inside tiny
blocks of materials such as smart polymers or thermosensitive hydrogels. The temperature
responsive polymers respond quickly when there is an increase in temperature by a few
degrees. Current simulations and theoretical studies in the research reveal that there is a
considerable rise in temperature inside the polymers due to the interaction of the microparticles with the electromagnetic radiation.
Incident microwaves heat the metallic particles causing a rise in temperature inside the hydrogel
leading to contraction and release of the drug loaded particles.
Consequently, microwaves can be used for heating of metallic micro-particles embedded inside
such smart hydrogels. The heating effect can then be utilised for externally triggered drug
release. Further, the ISM band can be used in this technique for taking advantage of the already
established standards regarding safety considerations and no license requirements. Thus,
efficient design considerations can be used to design an effective drug delivery system which
delivers low powered, non-ionising microwave signals to drug loaded implants inside the
human body for controlled drug delivery. This work lays the foundation of the device to be
used in many attractive applications such as drug delivery and remote triggering of
electromagnetic microsystems.
S11 parameters and Simulated Electric field of the Modified SRR [1]
[1] Shaikh, M.S., Donnan, R.S., Dubrovka, R.F., "Heating Effect of the Electromagnetic Interaction
with Metallic Microparticles", European Conf. on Antennas and Propagation, EuCAP 2021, paper
#1570686908
Interaction with the Body across the frequency bands (SAR, SA and
power density compliance Assessments)
Yasir Alfadhl, Xiaodong Chen
The Specific Absorption Rate (SAR) is used in dosimetry to denote the transfer of energy from
the EM fields to biological materials (rate of energy deposition per unit mass of tissue).
While SAR is the measure of the incremental EM power absorbed by a given mass for
continuous waves; the Specific Absorption (SA) [J/kg) is the quotient of the incremental energy
absorbed by the incremental mass contained in a volume over a pulse duration.
With the increased interest in applications associated with higher frequencies above 6GHz,
much more attention has been drawn to the assessments of the incident power densities to
assess the incremental EM power density as it is absorbed by the surface of the body.
To demonstrate the need to shift focus to surface tissues when exposure is at higher frequencies,
our studies have shown that E-field absorption are limited to skin layers, hence, the need to use
power density assessments rather than the usual SAR assessments.
Our studies involve the utilisation of experimental and numerical methods to investigate the
effects of EM wave absorption within tissues due to exposure to waves in the RF frequency
band and beyond, and to pulsed waves. The SAR/SA induced within the human body, especially
the head and brain, are typically evaluated by computing the absorption strength and the
location of peaks/maxima.
Understanding the underlying interaction mechanisms caused by EM exposure is necessary for
assessing the possible impact on human health. The interaction of EM fields with biological
systems can be categorised by several mechanisms, depending on the type and frequency of
exposure.
(a)
(b)
(c)
Examples of volume rendered images of the female model; (a) The outside surface; (b) Skin and
skeleton; (c) Skeleton with a few internal organs (Skin, Fat, and Muscle removed); (d) 240 million
FDTD/FIT voxels to compute the body accurately.
EM Absorption within the Body vs. Age
Yasir Alfadhl, Xiaodong Chen
Our studies include investigations on the effects of ageing on the level of interaction with EM
fields, and whether such changes may have different implications on the human or animal wellbeing. Ageing variations have included the impact of body size changes, changes to dielectric
properties due to ageing and other factors.
Example of comparison between age-dependent properties of skull tissue dielectric properties.
Examples body SAR(10) distributions due to planewave exposure at 868MHz, under sleeping
condition. The figure represents the difference in peak values for female, male and child models.
SAR distribution resulting from exposure close to smart-meter antennas [1]; (a) whole-body SAR
(WBSAR); (b) Max. SAR (10g); when models are under sleeping condition and exposed from top to
bottom at 15cm distance.
[1]Qureshi, M. R. A., Alfadhl, Y., Chen, X., Peyman, A., Maslanyj, M., & Mann, S. (2018). "Assessment
of exposure to radio frequency electromagnetic fields from smart utility meters in GB; part II)
numerical assessment of induced SAR within the human body", Bioelectromagnetics, 39(3), 200216. doi:10.1002/bem.22094
Macroscopic and Microscopic Electroporation Studies
Yasir Alfadhl, Xiaodong Chen
As part of the Electromagnetics and Antenna activities, the group has focused on the
interactions of electromagnetic waves with biological matter (specifically on the cellular, subcellular and molecular levels), both experimentally and numerically. Electroporation is a nonthermal scheme based on applying short but intense pulses to the biological cells or tissues.
The conductivity and permeability of the cell membrane can be increased dramatically during
the process, which allows the large-sized molecules to flow through in both directions.
Molecular dynamics presents a microscopic view of electroporation that conventional
observations cannot. Although the method has some challenges, it can be used to reveal some
fundamental behaviour at the atomic level that is later confirmed from the experiment.
Therefore, we have a number of studies where we combine the molecular dynamics
observations with the experimental results to deepen the understanding of the electroporation
process.
In our studies, we use evidence-supported-theory to describe the process of cellular
electroporation by the means of experimental applicators with state-of-the-art sources and
measurement methods, complemented with numerical computations of the molecular
interactions with the fields applied (using Molecular Dynamics computation tools).
Assessment of dielectric properties and body composition
Yasir Alfadhl, Xiaodong Chen, Hasan Sagor
The interaction of EM waves with matter is depend on a number of parameters, one of which is
the dielectric properties of the exposed material. In our studies, we apply various techniques to
(i) study the effects of the variation of these properties within the exposed body; and/or (ii)
estimate the characteristics of the exposed material by applying the inverse process. The latter
is rather important, not only to predict the composition of the body (e.g., fat layers, etc.), but
also to detect potential abnormalities within the body, such as cancerous regions. The
techniques applied many include any of the impedance measurements, EM imaging, or
dedicated scanning or radar techniques.
Calibration of the Agilent Dielectric Probe using deionised water.
Nano-particle Applications in Medical Fields
Research into the applications of Nano-particles (NPs) has found increased interest in
diagnostics, imaging, and therapeutics in biology and medicine. In particular, Gold nanoparticles (GNPs) have received much attention, because of their distinctive optical, electronic,
and molecular-recognition properties. In medical applications, we look into the potential
applications of GNPs for better targeting of EM-generated hyperthermia treatments of cancer.
In essence, the EM illumination of GNPs can result in energy absorption and selectively heat
and abolish tumour regions without affecting healthy tissue. In other studies, we explore the
potential of targeted NPs for non-invasive ablation and drug delivery in radiofrequency (RF)
EM fields. These studies aim to reveal the mechanism of GNPs heating under exposure, to study
the molecule-targeting procedure of NPs, and to optimise the delivery of GNPs directed via
novel antenna systems.
Other examples of Bio-EM projects
One example is the non-invasive monitoring of blood glucose levels (BGL). The electromagnetic
properties of the body vary with BGL, which means the response of some resonator or EM
device placed on the body will also vary, in theory, with the changes in BGL. Understanding this
relationship is key to producing an EM sensor that can determine such physiological signals,
which avoids the need for even minimally-invasive bio-sensor approaches. On the other hand,
the use of ingestible or implantable wireless devices also requires an understanding of the
interrelationship between the device and the surround tissue(s). Work in this area includes the
development of digital and physical tissue phantoms (such as that in the header image above),
the development and characterisation of microwave devices for wireless wearable
physiological monitoring systems, and investigations to quantify the relationship between the
various physiological parameters and the microwave response, including subject-specific
variations.
The effect of biological tissues on electromagnetic waves can also be utilised for imaging
purposes. The most well-known examples of this are X-ray imaging systems and the related Xray Computed Tomography (CT) imaging systems. X-ray imaging finds application in
healthcare (ranging from dentistry to imaging of the whole body), security (e.g., airport
scanners) and industry (e.g., checking for structural integrity of pipes). However, X-rays are an
ionising form of electromagnetic radiation, with associated health risks. Lower-energy nonionising waves, such as at the THz, millimetre-wave and microwave frequency bands, can also
be used for imaging, without the risks of X-rays.
Our studies in this domain include assessments of the effects of EM waves on the general
public, EM biological anomalies detection methods, medical imaging schemes using EM waves,
studies on the latest state-of-the-art medical treatments, and enhanced EM-assisted drugdelivery methods.
Highlights and Research Outcomes
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The group’s work on the numerical dosimetry of the interaction of waves emitted from
smart meters on the population (based on male, female and children numerical models)
have been used by Public Health England to provide exposure safety guidelines for the
public.
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A range of novel devices and techniques have been developed to enhance the efficiency,
accuracy, and to create state-of-the-art solutions to everyday challenges. Examples of
such developments include (not exclusive to) novel exposure cavities, solid-state nanosecond pulse generators for cancer treatments, novel near- and on- body
communications and matched novel antennas for diagnostics and treatment.
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The group’s contributions on the assessment of electromagnetic properties of biological
tissues has resulted in increased accuracy of bioelectromagnetic problems and in
assessing the interactions between electromagnetic fields and the human body.
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The group's research activities in modelling and characterisation of Gold Nano-particles
for medical treatment and diagnosis (Liu X, Chen HJ, Chen X et al., "Low frequency
heating of gold nanoparticle dispersions for non-invasive thermal
therapies", Nanoscale vol. 4 (13) 3945-3953, 2012) was cited and mentioned in a
recent Science Review paper: Hong Koo Kim et al., "Are Gold Clusters in RF Fields Hot or
Not?", Science 340, 441 (2013), DOI: 10.1126/science.1237303
Selected Research Grants and Projects
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"Smart Meter Project", Public Health England (PHE) project on SAR assessments duet to
Smart Meters (ITT_873) 2014/15
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"Novel clinical nano-second electroporation device for cancer treatment", EPSRC IoB
programme grant 2015.
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Assessment of the interaction of EM signals from Smart-Meters on the general
population” (Public Health England) 2014.
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“Wearable and implantable antennas for in- and on-body applications”, 3Y-FT PhD
studentship, 2014.
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“Abdominal Fat Detection technique using EM waves”, 5Y-PT PhD studentship, 2014.
Selected Recent Publications
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Sarjoghian, S., Rahimian, A., Alfadhl, Y., Saunders, T. G., Liu, J., & Parini, C. G. (2020).
Hybrid development of a compact antenna based on a novel skin-matched ceramic
composite for body fat measurement. Electronics (Switzerland), 9(12), 1-13.
doi:10.3390/electronics9122139
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Rao, X., Chen, X. D., Zhou, J., Liu, Y. Y., & Alfadhl, Y. (2020). Study on the Apoptosis
Mechanism of Murine Melanoma B16 Cells Stimulated by Nanosecond Pulse Electric
Field. Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and
Technology of China, 49(6), 949-954. doi:10.12178/1001-0548.2020099
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Rao, X., Chen, X., Zhou, J., Zhang, B., & Alfadhl, Y. (2020). Design of a high voltage pulse
generator with large width adjusting range for tumor treatment. Electronics
(Switzerland), 9(6), 1-11. doi:10.3390/ELECTRONICS9061053
Body-Centric Wireless Communications
The development of wearable computer systems has been growing rapidly. These are
becoming smaller and more lightweight; no one wants to wear a bulky and heavy computer all
day! We will soon see a wide range of unobtrusive wearable and ubiquitous computing
equipment integrated to into our everyday clothes. In a possible wearable computer, the
monitor/display would be on a pair of glasses, the keyboard worn on the wrist, and the
motherboard worn on the waist. It is undesirable to use bulky cables to connect these devices,
so communication will be wireless, using an antenna.
The human body is an uninviting and often hostile environment for a wireless signal. Compact
yet efficient antennas need to be fully characterized and integrated with the RF transceiver.
Some of these are conformability and immunity to frequency and polarization detuning. It is
important to understand material properties of fabrics and potential use of microwave
metamaterials to minimize the specific absorption rate (SAR).
We are working on the important issue of the design of such an antenna. We are particularly
considering the following issues:
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The antenna itself must be small and lightweight, since it is part of a lightweight device;
The small size of the antenna must not reduce its performance;
The antenna structure must be designed to have limited radiation power in the
direction of the wearer, to minimize possible health problems;
The transmission power must be low, to prolong battery life and hence operating time.
Textile conformal antennas to provide user-friendly solutions
Surface guided wave antenna to improve on-body communications
Radio propagation in complex environments and considering dispersive human tissues
System-level modelling for potential narrowband and ultra wideband communication
systems.
Covering a wide range of frequecy up to Terahertz for nano-scale networks
Wearable Sensor Antennas have to be compact and easily integrated. They should be immuned
from de-tuning and performance degradation due to surrounding components and when
placed on the body. They should have high efficiency to achieve maximum radiated power to
enlarge coverage area specifically for communication between body mounted devices and base
units/access points. It is also needed in the wireless sensor antenna design to overcome
shadowing problems caused by the human body and the dynamic environment.
Antennas and Propagation for Wireless Implants
Wireless Implants provide flexibility to the patience and the surgeon in terms of replacement
and long lifetime. They have advantages of maintaining constant availability and ease of
operation, which are required for future patient monitoring and diagnosis systems.
Applications include but not limited to:
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Accurate drug delivery.
Non-Invasive Endoscopy.
Patient diagnosis and locator.
Muscle stimulator.
Brain signals analysis and control.
The group has had many successful collaborations including an ongoing research with the
National Research Centre for Bowel Disease and Barts and The London on localisation and
tracking wireless endoscope for future efficient patient-centric endoscopy.
UWB Antennas and Their Applications in the Home Environment
UWB provides High capacity, Multipath robustness, Fine time resolution for accurate delay
estimate, Low transmission power, Inexpensive systems and Multi-access. Dispersion of human
tissues across the frequency band needs to be considered in on-body antenna and propagation
characterisation. Usually, non-dispersive antennas are required for optimum performance with
radiation that minimises path loss across UWB band. Since UWB is Impulse Radio technology,
received pulse shape and property is of great importance.
Wearable Antennas and Sensors
The group has been working in collaborations with material scientists at QMUL, The Royal
College of Art, Loughborough University and Nottingham University to push the boundaries for
textile based antennas and EM devices and structures going beyond wearable antennas to
complex metamaterials. Activities inlcude Graphene-based soft antennas with efficient
performance for near field and medium range application to be first screen print and tested in
our labs.
Nano-scale body-centric communications and networks at THz
With the development of nanotechnology, the idea of connecting nano-devices to conduct
complicated tasks and communicate the information collected by these devices was a natural
progression in order to complete the overall picture of a new generation of connected devices.
As a consequence, nano-networks were proposed by the IEEE standardization group (P1906.1 Recommended Practice for Nano-scale and Molecular Communication Framework, which the
principal supervisor is a member of) and therefore the need for nano-communication was a
necessity. Nano-networking is the study of communication among devices and/or entities –
manmade, biological, and hybrid – with very small dimensions; challenging physical features of
this communication environment make analysis and system design very different from
conventional communication systems. Nano-networking is a rapidly emerging discipline, but as
yet (1) emerging technology trends and important open problems in this area are unclear; and
(2) new industrial applications need to be identified. Although we have a comprehensive
understanding of wireless body sensors and other cellular networks, how nano-devices
communicate inside or around the body is still an open research challenge. It is generally
accepted that molecular communication is the most promising method to transfer information
between nano-devices when it comes to bio-applications. But is there any possibility to adopt
the electromagnetic (EM) communication paradigm at nano-scale? Adopting EM
communication will create an easier path for larger networks and also allow the use of varying
technologies and data rate based on the scenario of concerned.
The group has been active in recent years in theoretical, numerical and experimental research
focused on the proof of concept and validation of the down scaling of the body-centric wireless
communication networks to the nano-scale and enjoyed grant funding from national and
international research councils, industries and chartities. The group collaborated with leading
experts from USA, UK, EU, Japan, Singapore, Qatar, UAE and many more. The group was also a
lead contributor to the IEEE P1906.1 Nano-scale and Molecular Communication Framework
and also an active member of the IEEE SC THz standardisation group.
The applications range from comprehensive healthcare monitoring, localised tissue detection
of deformations (e.g. skin biological deformation monitoring), chemical compound recognition
and high data rate confined and secured next generation communication.
Highlights and Research Outcomes
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The group has published 5 books, more than 12 book chapters and more than 500
substantial journal and refereed conference papers on Body-Centric Wireless
Communications.
This work is in collaboration with many academic partners (Imperial College London,
University of Birmingham, etc.) and industrial collaborators (DSTL, Philips Research, GE
Global Research, Toumaz Technologies Ltd., etc.)
The group has organised/co-organised 5 workshops related to body-centric wireless
networks sponsored by the European School of Antennas, and more than 5 focused
seminars.
Academics in the Antennas Group involved in body-centric research have been invited
to deliver special talks and keynotes in many international conferences organized by
the IEEE and IET
Prof. Yang Hao was elected as IEEE Fellow in 2013 in recognition of his contributions to
body-centric wireless communications.
Various media appearances and international exposure related to wearable electronics.
Selected Research Grants and Projects
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PAMBAYESIAN: PAtient Managed decision-support using Bayesian networks, EPSRC
Intelligent Technologies for Collaborative Care Fund (Total for consortium £1.6m, July
2017 – June 2021)
Numerical Analysis and In-vitro Demonstrator of Small-scale Communication Networks
for Healthcare Monitoring Applications – Qatar National Research Foundation NPRP
fund with Texas A&M University at Qatar (£550k, Feb 2015–Jan 2018)
EPSRC Off-campus Business Engagement Fund– EPSRC funding through QMUL internal
competition (£12.5k, Jan–Apr 2015)
EPSRC CDT Capital Equipment Fund for Media and Arts Technology Doctoral Training
Activities, (£314k, Sept 2014)
UWB Antenna Front-end Solutions for Localisation and Tracking, Consultancy for
Sportable Technologies Ltd., (September 2019 – April 2020)
MASH: Millimetre-wave AI-enabled Smart Healthcare monitoring, Innovate UK – Lead
by NodeNS Medical Ltd. (Total of £31k, February – September 2019)
Atrial Fibrillation Prediction Using WBAN-ECG Monitoring System, Abu Dhabi
Department of Education and Knowledge (ADEK) Award for Research Excellence 2018
– Lead by Al Ain University of Science and Technologyand in collaboratrion with
University of Glasgow UK (Total of £90k, January 2019 – December 2020)
Sensing the Human Skin for Medical Diagnostic and Prevention in Personalised
Healthcare Applications, Abu Dhabi Department of Education and Knowledge (ADEK)
Award for Research Excellence 2017 – Lead by UAE University and in collaboratrion
with University of Glasgow UK (Total of £90k, January 2018 – December 2019)
Design, fabrication and ex vivo validation of a body-centric localisation and tracking
system for use in a robotised wireless capsule endoscope – QMUL Life Sciences
Initiative Proof of Concept Fund (£50k, January – December 2018)
PATRICIAN: New Paradigms for Body Centric Wireless Communications at MM
Wavelengths, in total, £1.2M EPSRC, with University of Birmingham and Durham
(2011.1 – 2014. 12)
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Reduction of Energy Demand in Buildings through Optimal Use of Wireless Behaviour
Information (Wi-be) Systems”, in total £600K, EPSRC, with University of Nottingham,
Reading (2010.8 – 2013.7)
Selected Recent Publications
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Khan AN, Ihalage AA, Ma Y, Liu B, Liu Y, Hao Y (2021) Deep learning framework for
subject-independent emotion detection using wireless signals. PLoS ONE 16(2):
e0242946. https://doi.org/10.1371/journal.pone.0242946
Akram Alomainy, Ke Yang, Muhammad A. Imran, Xin-Wei Yao, Qammer H. Abbasi (eds.),
"Nano-Electromagnetic Communication at Terahertz and Optical Frequencies:
Principles and Applications", The Institute of Engineering and technology (IET),
November 2019. ISBN-10: 1-78561-903-9 and ISBN-13: 978-1-78561-903-8
Qammer H. Abbasi, Masood Ur Rehman, Khalid Qaraqe and Akram Alomainy (eds.),
"Advances in Body-Centric Wireless Communication: Applications and State-of-the-art"
, The Institute of Engineering and technology (IET), July 2016. ISBN: 978-1-84919-9896
K. Yang, D. Bi, Y. Deng, R. Zhang, M. M. Ur Rahman, N. Abu Ali, M. A. Imran, J. M. Jornet, Q.
H. Abbasi, and A. Alomainy, "A Comprehensive Survey on Hybrid Communication in
Context of Molecular Communication and Terahertz Communication for Body-Centric
Nanonetworks", in IEEE Transactions on Molecular, Biological and Multi-Scale
Communications, vol. 6, no. 2, pp. 107-133, Nov. 2020, doi:
10.1109/TMBMC.2020.3017146.
Robel, M.R.; Ahmed, A.; Alomainy, A.; Rowe, W.S.T., "Effect of A Superstrate on On-Head
Matched Antennas for Biomedical Applications", Electronics 2020, 9, 1099.
I. Ibanez-Labiano, M. S. Ergoktas, C. Kocabas, A. Toomey, A. Alomainy, E. Ozden-Yenigun,
"Graphene-based Soft Wearable Antennas", Applied Materials Today, Volume 20,
September 2020, 100727 (https://doi.org/10.1016/j.apmt.2020.100727).
W. Belaoura, K. Ghanem, M. A. Imran, A. Alomainy and Q. H. Abbasi, "A Cooperative
Massive MIMO System for Future In Vivo Nanonetworks", in IEEE Systems Journal, doi:
10.1109/JSYST.2020.2995671.
Ibanez-Labiano, I.; Alomainy, "A. Dielectric Characterization of Non-Conductive Fabrics
for Temperature Sensing through Resonating Antenna Structures", Materials 2020, 13,
1271.
A. Rizwan, N. Abu Ali, A. Zoha, M. Ozturk, A. Alomaniy, M. A. Imran and Q. H. Abbasi,
"Non-invasive Hydration Level Estimation in Human Body using Galvanic Skin
Response" in IEEE Sensors Journal, vol. 20, no. 9, pp. 4891-4900, 1 May1, 2020, doi:
10.1109/JSEN.2020.2965892.
R. Zhang, K. Yang, B. Yang, N. A. AbuAli, M. Hayajneh, M. P. Philpott, Q. Abbasi, A.
Alomainy, "Dielectric and Double Debye Parameters of Artificial Normal Skin and
Melanoma", J Infrared Milli Terahz Waves 40, 657–672 (2019).
https://doi.org/10.1007/s10762-019-00597-x.
M. Ilyas, O. N. Ucan, O. Bayat, A. A. Nasir, M. A. Imran, A. Alomainy, Q. H. Abbasi,
"Evaluation of Ultra-wideband In-vivo Radio Channel and Its Effect on System
Performance", Trans Emerging Tel Tech. 2019;30:e3530.
P. Leelatien, K. Ito, K. Saito, M. Sharma and A. Alomainy, "Numerical Channel
Characterizations for Liver-Implanted Communications Considering Different Human
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Subjects", IEICE Transactions on Communications, Article ID 2018EBP3050, October
2018.
A Pellegrini, A Brizzi, L Zhang, K Ali, Y Hao, et al, Antennas and Propagation for BodyCentric Wireless Communications at Millimeter-Wave Frequencies: A Review [Wireless
Corner], Antennas and Propagation Magazine, IEEE 55 (4), 262-287.
Antenna Metrology Theory and Applications
As well as having high quality antenna measurement facilities, the group undertakes research
into microwave and millimetre-wave antenna metrology. This research is focused around the
major antenna measurement facilities of the Antenna Measurement Laboratory, consisting of:
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two compact antenna test range operating from 5 GHz to 300 GHz;
fully-screened anechoic chamber for mobile communications antenna applications
(750 MHz to 5 GHz);
NSI Planar near-field range operating to 100 GHz;
A 9 m x 3 m x 3 m anechoic chamber for feed measurements and general measurement
use;
A NSI-700S-360 Spherical Near Field antenna measurement system housed in a
purpose built anechoic chamber 4.4m long, 3.1m wide and 3.1m high and operating at
frequencies up to 500 GHz.
A significant amount of our antenna metrology research is published in the following books:
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‘Principles of Planar Near-Field Antenna Measurements’, S. Gregson, J. McCormick, C.
Parini, IET Electromagnetic Wave Series, 2007, ISBN 978-0-86341-7368. https://digital-library.theiet.org/content/books/ew/pbew053e. A comprehensive
text covering the theory and practice of planar Near-field antenna measurement.
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'Theory and Practice of Modern Antenna Range Measurements - 2nd Expanded edition
in two volumes', c. Parini, S Gregson, J. McCormick, D. van Rensburg, T. Eibert, IET
Electromagnetic wave series, IET , 2020, ISBN 978-1-83953-126-2 & ISBN 978-183953-128-6. https://shop.theiet.org/theory-and-practice-of-modern-antenna-rangemeasurements-2nd-edition-2. Provides a comprehensive introduction and explanation
of both the theory and practice of all forms of modern antenna measurements, from
their most basic postulates and assumptions, to the intricate details of their application
in various demanding modern measurement scenarios.
Some of our Antenna Metrology research is illustrated by the following
activities.
Mathematical Absorber Reflection Suppression (MARS)
Stuart Gregson & Clive Parini
This mathematical post-processing technique can be deployed to antenna pattern data taken
using a far-field or CATR facility using only a single great circle cut to efficiently correct farfield, frequency domain data. Reflections in a CATR can often be the largest source of
measurement error within the error budget of a given facility. This mode orthogonalisation and
filtering technique requires only a minimum amount of information about the AUT and
measurement geometry, and is able to suppress reflections in a direct far-field one-dimensional
antenna range measurement.
Contrary to usual antenna measurement practice, the MARS technique deliberately displaces
the AUT from the centre of rotation on the turntable. This has the effect of making the
differences in the illuminating field far more pronounced than would otherwise be the case,
and it is exactly this greater differentiation that makes their identification and subsequent
extraction viable. Once the far-field great circle pattern cut has been acquired in this displaced
condition, the AUT pattern can be mathematically translated back to the origin of the
measurement co-ordinate system and from this, the equivalent cylindrical mode coefficients
(CMCs) can be deduced from the measured fields.
The cylindrical mode coefficients for the, now ideally centrally located, AUT are then recovered,
so any mode representing fields outside the ideal conceptual minimum MRE can be filtered out,
thereby removing contributions that are not associated with the AUT. As these transforms and
their inverse operations can be evaluated with the fast Fourier transform (FFT) this makes the
F-MARS algorithm very efficient in terms of computational effort.
To demonstrate the method, repeat measurements were taken of the far-field great circle
azimuth cut of a medium gain X-band corrugated horn in the QMUL CATR (see figure 1 below),
where a single parametric change was introduced into the measurement. This change consisted
of introducing a 0.6 m by 0.6 m flat reflecting plate into the chamber that was located in the
same horizontal plane as the AUT, and was chosen as it constituted a worst-case configuration,
as the specular reflection of the main beam of the corrugated horn directly illuminated the
CATR reflector. Figure 2 below shows the great-circle far-field co-polar amplitude and phase
patterns of the AUT, where the reference trace was taken without the reflecting plate.
Conversely, the measured trace was taken with the reflecting plate installed within the
chamber and clearly shows the effects of the additional scattering as an additional large
amplitude side-lobe at around 50°.
Figure 1: corrugated horn in the CATR facility.
Figure 2: Power and phase patterns for the corrugated horn.
From inspection of the F-MARS processed patterns, it can be seen that the effects of the
spurious scatterer have been effectively suppressed in both the amplitude and phase plots.
Details can be found at:

S.F. Gregson; C.G. Parini; A.C. Newell, "A General and Effective Mode Filtering Method for
the Suppression of Clutter in Far-Field Antenna Measurements", 2018 AMTA
Proceedings. https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8604219
Poly-Planar Near-Field Measurements
Stuart Gregson & Clive Parini
Conventional single cut planar near-field measurements are restricted to high-gain antennas
and to radiation pattern angles covering much less than the forward hemisphere, due to the
truncation of the extent of the planar surface that the radiation fields are measured. We have
developed techniques to combine several near-field planar scans to calculate the far-field
radiation pattern of a given AUT, to much wider angles, and indeed full spherical coverage.
As an example, we demonstrate a poly-planar technique in which the AUT is mounted in one of
six discrete orientations, these orientations being the positive and negative directions of the
three orthogonal positional axes. This cubic geometry is the most demanding case, as the
orthogonality between adjacent partial scans would constitute a worst case scenario whilst
being relative simple to realise. Using our NSI planar scanner and the corrugated horn (shown
in Figure 3) as the AUT, all six surfaces of the cube surrounding the AUT were sampled by
performing the following rotations from position:
1.
2.
3.
4.
5.
AUT nominally aligned to axes of range;
positive rotation of 90° about y-axis;
negative rotation of 90° about y-axis;
positive rotation of 180° about y-axis;
positive rotation of 90° about z-axis, followed by a positive rotation of 90° about new xaxis;
6. positive rotation of 90° about z-axis, followed by a negative rotation of 90° about new xaxis.
The requirement for the inclusion of the back plane follows from the requirement to perform
the pattern integration over a closed surface. When the partial scans were completed each of
the six partial scans were processed using our transformation algorithm. The y-polarised
electric near-field can be found plotted below and as expected, the fields at the intersection
between adjacent partial scans are continuous.
Figure 3: Corrugated horn and the NSI near-field scanner.
These cubic data sets were subsequently transformed to the far-field and resolved onto a
Ludwig III polarisation basis. An example pattern is shown below, where the blue trace
represents patterns obtained from the poly-planar technique, whilst the red trace denotes
results obtained from our compact antenna test range (CATR). The high frequency oscillatory
behaviour evident within the azimuth cut of the CATR at wide angles is a result of multiple
reflections within the facility and should be ignored.
Details can be found in chapter 9 of:

S.F. Gregson, J. McCormick, C.G. Parini, “Principles of Planar Near-Field Antenna
Measurements”, The Institution of Engineering and Technology, UK, 2007.
Figure 4: Y-polarised electric field for the six surfaces.
Figure 5: Comparison of far-field patterns from the Poly-Planar Near-field and CATR
measurements.
Examining and Optimizing Compact Antenna Test Ranges for 5GNR
OTA Massive MIMO Multi-User Test Applications
Stuart Gregson & Clive Parini
Direct far-field testing has become the baseline test methodology for sub-6 GHz over the air
(OTA) testing of the physical layer of radio access networks with the far-field multiprobe
anechoic chamber (FF-MPAC) being widely utilized for the test and verification of massive
multiple input multiple output (Massive MIMO) systems when operating in the presence of
more than a single user. The utilization of mm-wave bands within the 5th generation new radio
(5GNR) specification has necessitated that since the user equipment should, preferably, be
placed in the far-field of the base transceiver station (BTS) antenna, excessively large FF-MPAC
test ranges are required or, alternatively the user equipment is paced at range-lengths shorter
than that suggested by the classical Rayleigh criteria. However, contrary to this, a recently
proposed solution involves the use of a novel Parabolic Toroid Compact Antenna Test Range
(PT-CATR). This is especially well suited to the needs of 5G OTA testing and we have
quantitatively verified its success by assessing the measurement of common communication
systems performance metrics.
Figure 6: Left: Azimuth geometry of full PT CATR for full +/-60° of horizontal scan. Right: side
view of system with robotic arm providing feed movement that gives +/-15° beam scanning in
vertical plane.

S.F. Gregson; C.G. Parini, "Examining and Optimizing Compact Antenna Test Ranges for
5GNR OTA Massive MIMO Multi-User Test Applications",2020 Antenna Measurement
Techniques Association Symposium (AMTA)

S.F. Gregson, C.G. Parini, “A Parabolic Torus Compact Antenna Test Range for 5G NR
Massive MIMO OTA Multi-User Test Applications”, IEEE International Symposium on
Antennas and Propagation and North American Radio Science Meeting, 5-10 July 2020,
Montré al, Qué bec, Canada.
Examining and Optimising Far-Field Multi-Probe Anechoic
Chambers for 5GNR OTA Testing of Massive MIMO Systems
Stuart Gregson & Clive Parini
Direct far-field (DFF) testing has become the de facto standard for sub-6 GHz over the air (OTA)
testing of the physical layer of radio access networks with the far-field multi- probe anechoic
chamber (FF-MPAC) being especially widely deployed for the verification of massive multiple
input multiple output (Massive MIMO) antennas in the presence of several users. The adoption
of mm-wave bands within the fifth generation new radio (5G NR) specification has meant that,
as these systems require the user equipment be placed in the far- field of the base transceiver
station (BTS) antenna, either excessively large FF-MPAC test systems are required or, the user
equipment is paced at range-lengths very much shorter than that suggested by the classical
Rayleigh criteria. In this work we explored range length effects on several communication
system figures of merit and examines the consequences of testing within smaller enclosures.
Resulting the the Variable Far-Field Distance Chamber design shown below.
Figure 7: Variable FF distance chamber design for FF-MPAC compared with traditional FF-MPAC.
Figure 8: Effective FF distance for azimuth scan angles for the variable FF distance chamber
design for FF-MPAC.

S.F. Gregson; C.G. Parini, "Examining and Optimising Far-Field Multi-Probe Anechoic
Chambers for 5GNR OTA Testing of Massive MIMO Systems", 2020 14th European
Conference on Antennas and Propagation (EuCAP)
Computational electromagnetic modelling of compact antenna test
range quiet zone probing: A comparison of simulation techniques
Clive Parini, Rostyslav Dubrovka & Stuart Gregson
This work concerns an EM simulation study predicting the quality of the pseudo plane wave of
a single offset compact antenna test range (CATR). We have extended our previous quiet-zone
performance predictions to rigorously incorporate the effects of probing the CATR quietzone
using arbitrary but known field probes. This paper compares and contrasts results obtained
using plane-wave spectrum and reaction integral based simulation techniques. This
investigation leads to recommendations as to the optimal field probe choice and measurement
uncertainties.
Figure 9: Simulated CATR QZ measurement using planar transmission formula.
Simulated the probed CATR QZ using a SGH probe – industry standard; Simulated the CATR QZ
assuming an infinitesimal electric dipole, “theory”. SGH reduces high spatial frequency ripple






C.G. Parini; R. Dubrovka; S.F. Gregson, "Computational electromagnetic modelling of
compact antenna test range quiet zone probing: A comparison of simulation
techniques", 2016 10th European Conference on Antennas and Propagation (EuCAP)
Electromagnetic Compatibility
Stochastic Electromagnetic Fields in Dynamic Multipath
Environments
Luk Arnaut
Electromagnetic compatibility (EMC) concerns itself with electronic interference, noise
phenomena and coexistence between electronic systems. The emphasis is on natural
and unintentional EM radiation or conduction, as opposed to man-made intentionally
designed radiation structures. Traditionally, the domains of investigations in EMC have
been subdivided into immunity, emission and shielding. With the proliferation of digital
equipment, additional domains of research including spectrum management
(particularly ultra-wideband phenomena), modulation and fading, dynamic and
complex EM environments, signal and power integrity, total radiated power and
desense.
Research at QMUL focuses on reverberation chambers as a canonical environment for
dynamic multipath propagation, standardized EMI testing and high-mobility wireless
communications at the physical layer. Compared to ideal random fields, the analysis of
deviations from ideal statistical isotropy, homogeneity, depolarization and incoherence
in idealized chambers are fundamental to uncertainty quantification (UQ) for the
estimated field strength and power density. As tunable multimode high-Q cavities,
mode-tuned rand mode-stirred everberation chambers find applications in areas from
RF to optical wavelengths and at different length scales, including micro- and nanoscale
resonators. A prime focus is on extreme EM fields, level crossings exceedances,
excursions and excesses of energy above high or low threshold levels, which has led to
probabilistic and stochastic characterizations of their metrics, including their
uncertainty. The development of a theory for the spectral representation and FokkerPlanck equations of nonstationary fields offers a framework for a deeper understanding
of the role of correlation and nonlinear dependence.



Figure 1: (a) Scatter plot and (b) magnitude of normalized complex electric field in a
mode-stirred reverberation chamber (blue), including excursions above (red) and below
(turquoise) threshold levels.

Figure 2: I/Q components, amplitude and phase of received pulse amplitude modulated
field inside a mode-stirred reverberation chamber at stir speed 0.25 rev/s.



Figure 3: (a) Copula, (b) relative copula, and (c) empirical copula density for extreme
random fields at l/V1/3=0.069.

Figure 4: Paddle transients in mode-tuned operation.



Figure 5: Estimated confidence limits of normalized Q-factor of a mode-tuned
reverberation chamber 0.1-6.1 GHz.

Figure 6: Components of average Maxwell stress dyadic áTñ for linear and orbital angular
momentum (OAM) of monochromatic random fields at wavenumber k and distance z from
a perfectly conducting boundary, based on Monte Carlo simulation of plane-wave
spectrum of random plane waves.



Figure 7: (a) Mean and (b) standard deviation of excess energy in regression
approximation of Slepian-Kac model