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Award details

University of Exeter funding: Tensorial Impedance Surfaces for An

CDT in Metamaterials (ICASE PhD studentship): Next generation metasurfaces: tensorial surfaces for novel antenna functionality Ref: 3398

About the award

Tensorial Impedance Surfaces for Antennas

Statement of Research

Joint supervisors: Prof Alastair Hibbins, Prof Roy Sambles, Dr Simon Horsley

External supervisor: Nathan Clow

Industry partner: DSTL

It is the focus of this project to design, model, fabricate and characterise 2D metasurfaces, or the surface 3D metamaterials or composites, that demonstrate a tensorial surface impedance.  When combined with appropriate antenna designs, the findings will support future civil applications like the internet of things, high frequency imaging systems for screening, scanners and tomography systems for medical diagnostics and wireless measurement and smart meter systems.

Propagation of energy along scalar impedance surfaces for the purpose of guiding and radiating electromagnetic waves has been studied for some time. Both 1-D and 2-D artificial impedance surfaces have been explored to control guided waves and leaky-wave radiation. Indeed the 'Sievenpiper-mushroom' array [1] is perhaps the best known metasurface, and Exeter researchers have successfully used an inhomogeneous design based on this to fabricate and experimentally test a surface-wave Luneburg lens device [2].  Similar structured surfaces can also be employed to reduce the height of antenna systems.  This is because, at their resonant frequency, the surface forbids the propagation of surface waves, and presents a magnetic-conductor boundary condition. Unlike perfect electric conductors, materials with this magnetic boundary condition do not exist in nature: it forces the tangential components of magnetic fluxes and the normal components of electric fields to be zero.  In this way radiating elements can be placed very close to the surface without the detrimental effects associated with the interference created by images sources induced by a simple metal ground plane.

This project takes our understanding beyond the current state-of-the art [3-6], and is centred around an exploration of coupling antenna eignenmodes to inhomogeneous and tensorial impedance surfaces. These metasurfaces can be those of the printed-circuit-board-type, or the surface of ‘bulk’ metamaterials or magnetic composites.  Initially we will work to understand the extent of the parameter space (in terms of the boundary conditions) that can be explored.  The next step is then to place a simple dipole source close to these surfaces to understand how they can influence the source’s radiation characteristics.  In turn, we will consider how the efficiency, functionality or directivity of more complex antenna can be improved, as well as reduction of size or thickness, and the polarisation of the radiated beam. A resulting structure that is lightweight, potentially conformal, and with compact volume, is particularly valuable to aerospace and space applications.

The challenges are numerous and difficult, but we expect great advances in fundamental understanding and device design from a competent researcher.  There are a wealth of studies in the scientific literature, and the researcher will be required to undertake a substantial review to provide the sponsors with a summary of the state-of-the-art on metasurfaces, and composite materials.  He or she will need to become familiar with the physics of anisotropic, layered and magnetic materials, and the fundamentals and complexities of wave optics.  The project will include analytical, modelling, fabrication and experimental elements, and the student will be expected to interact closely with other researchers working in related areas.

[1] D. Sievenpiper et al., “High-impedance electromagnetic surfaces with a forbidden frequency band,” IEEE Trans. Microw. Theory Tech., 47 (11), 2059, 1999.
[2] J. A. Dockrey et al., “Thin metamaterial Luneburg lens for surface waves,” Phys. Rev. B, 87, 125137, 2013.
[3] B. H. Fong et al., “Scalar and Tensor Holographic Artificial Impedance Surfaces,” IEEE Trans. Antennas Propag., 58 (10), 3212, 2010.
[4] R. Quarfoth and D. Sievenpiper, “Artificial Tensor Impedance Surface Waveguides,” IEEE Trans. Antennas Propag., 61 (7), 3597, 2013.
[5] A. M. Patel et al., “Effective Surface Impedance of a Printed-Circuit Tensor Impedance Surface (PCTIS),” IEEE Trans. Microw. Theory Tech., 61 (4), 1403, 2013.
[6] “Tensorial metasurface antennas radiating polarized beams based on aperture field implementation,” International Journal of Microwave and Wireless Technologies, 10 (2), 161, 2018.

The studentship is part of the UK’s Centre of Doctoral Training in Metamaterials (XM2) based in the Departments of Physics and Engineering on the Streatham Campus in Exeter.  Our aim is to undertake world-leading research, while training scientists and engineers with the relevant research skills and knowledge, and professional attributes for industry and academia.

The studentship is funded via the EPSRC Industrial Cooperative Awards in Science & Technology (CASE) scheme, via a grant awarded to DSTL.  The successful applicant  will normally be required to undertake regular reporting and visits to the sponsor.  For more details about the Industrial CASE scheme, see https://www.epsrc.ac.uk/skills/students/coll/icase.

The successful applicant will be registered on the XM² programme of study and follow that assessment and training programme. The student will not have the flexibility to change topic after the initial 6 month project.

The studentships are of value around £110,000, which includes £25,000 towards the research project (travel, consumables, equipment etc.), tuition fees, and an annual, tax-free stipend of approximately £16,500 per year.

Sponsor requirements dictate that applicants must be UK or EU Nationals.

Exeter has a well-established and strong track record of relevant research, and prospective students can consider projects from a wide variety of fields:

  • Acoustic and Fluid-dynamical Metamaterials
  • Biological and Bio-inspired Metamaterials
  • Graphene and other 2D Materials, and related Devices
  • Magnonics, Spintronics and Magnetic Metamaterials
  • Microwave Metamaterials
  • Nanomaterials and Nanocomposites
  • Optical, Infra-red and THz Photonics and Plasmonics
  • Quantum Metamaterials
  • Wave Theory and Spatial Transformations

Please visit www.exeter.ac.uk/metamaterials to learn more about our centre and see the full list of projects that we have on offer this year.

About XM2

XM2 is the doctoral training programme of our Centre for Metamaterial Research and Innovation 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.
In 2014, we started off as a £12 million Centre for Doctoral Training (CDT) in Metamaterials, funded by the Engineering and Physical Sciences Research Council (EPSRC/EP/L015331/1), the University of Exeter and industry.

The PhD students learn together in targeted courses, self-driven activity groups, and exposure to industry to gain scientific background knowledge beyond their areas of expertise, and to equip themselves with transferable professional skills such as creative thinking, project management, and leadership.
XM2 now consists of more than 60 active PhD students (Postgraduate Researchers, PGRs) from the UK, the EU and beyond, who are training in a stimulating, challenging yet supportive cohort-based environment. Since 2018, over 30 graduates went into employment in industry and as postdocs in Higher Education Institutions in and outside of the UK.

 

The University of Exeter combines world class research with excellent student satisfaction. It is a member of the Russell Group of leading research-intensive universities. Formed in 1955, the University has over 20,000 students from more than 130 different countries. Its success is built on a strong partnership with its students and a clear focus on high performance. Recent breakthroughs to come out of Exeter's research include the identification and treatment of new forms of diabetes and the creation of the world's most transparent, lightweight and flexible conductor of electricity.

We are one of the very few universities to be both a member of the Russell Group and have a Gold award from the Teaching Excellence Framework (TEF), evidence of our established international reputation for excellence in both teaching and research. Our success is built on a strong partnership with our students and a clear focus on high performance.
Exeter is also ranked amongst the world’s top 200 universities in the QS and Times Higher Education rankings.

How to apply

Application criteria

Eligible applicants: UK/EU nationals only.

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(s) you are applying for;
  • A Personal Statement consisting of two parts*:
    • 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.

Application procedure

Shortlisting

Applications will normally be reviewed within two weeks of receipt.
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 (minimum 2:1);
  • 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 one or more of the 8 research areas listed above;
  • 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 entry interview to assess fit to the CDT concept. This will be held prior the academic interview with the supervisors and will normally be undertaken by a panel of 3 people, including a current postgraduate researcher or post-doc in Physics or Engineering.

Interviews are expected to start within two weeks upon application receipt. It is therefore advisable to apply as soon as possible.

Please email metamaterials@exeter.ac.uk if you have any queries about this process.

Summary

Application deadline:30th November 2020
Number of awards:1
Value:The studentship is of value around £110,000, which includes £25,000 towards the research project (travel, consumables, equipment etc.), tuition fees, and an annual, tax-free stipend of approximately £16,500 per year.
Duration of award:per year
Contact: Dr. Isaac Luxmoore (Admissions Tutor) metamaterials@exeter.ac.uk