Furthering Electromagnetic Architecture of Buildings - An International Travel Application

Lead Research Organisation: University of Kent
Department Name: Sch of Engineering & Digital Arts

Abstract

The electromagnetic spectrum is a finite resource and frequency reuse is essential particularly in the mobile communications bands. Signal propagation in the built environment is notoriously complex but buildings are an environment where measures can be implemented to modify their electromagnetic architecture. Multiple occupancy commercial buildings, partitioned into offices, can in principle be electromagnetically screened internally to assist frequency reuse, and large, more open structures such as theatres can be shielded by suitable construction of the outer walls. It is common practice now, particularly in new buildings, to install aluminium foil backed layers within walls, as a fire precaution measure or for insulation purposes. Suitable screening can greatly reduce co-channel interference and our colleagues in Auckland have pointed out that an increase in the signal-to-interference ratio of just 10 or 15dB can decrease outage probability by an order of magnitude or more. At other frequencies access through the screen is necessary, especially at the emergency services band - at 400MHz in the UK, but apparently as low as 75MHz in New Zealand. In a very successful project funded by EPSRC and the National Policing Improvement Agency, we have been focussing on the application of Frequency Selective Surfaces (FSS) to the built environment with the emphasis on operation at the long wavelengths used in mobile communications. For example, a long-wavelength FSS intended to provide this emergency access while employing a minimum number of array elements has been based on simple square loop slot elements. An alternative approach is to reduce the array unit cell size, and this concept has led to a close collaboration with the Radio Systems Group at the University of Auckland who have extensive experience measuring and modelling the propagation of signals in buildings. Although FSS is an established technology, it is not well understood at mobile frequencies where the arrays are finite, elements may well be highly convoluted, layer separations are electrically small and room dimensions are comparable to the operating wavelengths. FSS design is challenging at mobile bands as they are far apart in fractional ratio terms. We have already installed in an office-type test room in Auckland a novel two layer FSS composed of highly convoluted elements. This work is ongoing, building on the work previously funded by the EPSRC. This application is for funding to enable the investigators to travel to Auckland on two separate occassions to work on three related topics: 1. to study the effect of FSS when mounted in small apertures, 2. to characterise FSS performance for high angles of incidence, 3. to assess the effect of wall mounted FSS on Wireless Computer Network performance in a specially built office-type room.

Planned Impact

The work summarised in this travel application impacts on two main areas: 1. on the building industry and the related civil engineering 2. on the efficient use of the radio spectrum, particularly at the wavebands used by mobile communications. The UK is a world leader at present in electromagnetic effects in the built environment. This project assists in maintaining this situation and spreading experience with the application of FSS to an international audience through, amongst other things, the bilateral experimental nature of the work and the consequential interchange of ideas and experience. The Auckland Group has long standing expertise in wave propagation in buildings, while we have decades of experience with Frequency Selective Surfaces. The two groups complement each other. We will work in New Zealand to build on the impact already created there by our existing work. We will use the knowledge gained to feedback into the UK's Wireless Friendly Buildings Forum. This fits in with both the 'challenge theme' defined by the Modern Built Environment Knowledge Transfer Network as a priority need, and with the UK Digital Economy Programme, 'novel design helping to transform lives'. There is, unfortunately, in our experience, a big gap between, on the one hand, the communications industry with its need to function efficiently in buildings, and on the other, the awareness of the requirements of good Electromagnetic Architecture on the part of civil engineers and architects who fabricate the built environment. Part of the impact will be a contribution towards bridging the gap and facilitating technology transfer. This is a relatively new area of engineering application and we have been able to contribute through two EPSRC funded projects in the past decade. These focused on the incorporation of Frequency Selective Surfaces, the first leading to interest from the Radio Communications Agency (now OFCOM) where for example Professor Parker was a member of a consortium led by ERA. One of the impacts of the second was the initiation of our collaboration with the Radio Systems Group at the University of Auckland, the continuing facilitation of which is the subject of this application for travel funds. We are also striving to inform the civil engineers of the importance of Electromagnetics in the built environment and this application forms part of this effort. A few years ago we were approached by one of the governors of our local prison regarding the illicit use of mobile phones. The prison service is an area where improved electromagnetic architecture could have obvious benefits. To quote from the BBC news website (23 November 2009) David Jamieson, chairman of Wandsworth prison's Independent Monitoring Board, says illegal phones fuel prison drug trading, bullying and gang problems. Behind bars, phones can cost 400 each. He said the trade had been worth 9m in 2008, when 7,000 phones were seized. Yet another area is in the design of theatres, our New Zealand colleagues pointed out to us that the cost of theatrical productions is so high, that investing in buildings where the unwanted use of phones could be prevented whilst permitting emergency service communications is not out of the question. In summary therefore, the impact of this work is the development of the electromagnetic architecture of buildings to enhance their wireless friendliness. To assist in propagating this benefit beyond academia we are already in discussions with civil engineering companies, for example, Waterman plc., we are members of the Wireless Friendly Buildings Forum, we have contacts with the Architectural Engineering Company Buro Happold, and the Home Office Scientific Development Branch (HOSDB). To quote a comment on some of our related work in this area this work could become 'an essential component in the radio planning and radio pollution armoury'.

Publications

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Bin Liang (2015) Cylindrical Slot FSS Configuration for Beam-Switching Applications in IEEE Transactions on Antennas and Propagation

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Gu C (2017) Dual-Band Electronically Beam-Switched Antenna Using Slot Active Frequency Selective Surface in IEEE Transactions on Antennas and Propagation

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Sanz-Izquierdo B (2011) Switchable Frequency Selective Slot Arrays in IEEE Transactions on Antennas and Propagation

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Sanz-Izquierdo B (2011) Wideband FSS for electromagnetic architecture in buildings in Applied Physics A

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Taylor P (2011) An Active Annular Ring Frequency Selective Surface in IEEE Transactions on Antennas and Propagation

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Taylor P (2010) Experimental phase plate employing a phase modulated active frequency selective surface in Microwave and Optical Technology Letters

 
Description This travel grant allowed three UK based researchers to visit complementary experts in indoor wireless propagation management through frequency selective surface integration into building infrastructure. The visit was to New Zealand where a test room was constructed for wireless testing with flexible panels of Frequency Selective Surfaces. A reciprocal visit to the UK resulted in outreach activity with the development of a web based wifi planning tool which illustrates the difficulties associated with providing reliable access in shared spaces.
Exploitation Route We have been asked to present our findings to HMGCC, the Home Office Scientific Development Branch, DSTL and to architectural consultancies based in London and Bath. We were also approached to provide technical information for an architectural consortium bid to equip the new Paris Law Centre.
Sectors Aerospace, Defence and Marine,Construction,Digital/Communication/Information Technologies (including Software),Electronics,Healthcare,Government, Democracy and Justice

 
Description The knowledge arising from this international collaborative project have led to discussions and agenda setting at the Wireless Friendly Buildings Forum (Led by Buro-Happold Architectural Consulting). We have also proposed and chaired special conference sessions at the IET and at Loughborough Antennas and Propagation Conference. In both cases the audience comprised mixed academic and industrial membership.
First Year Of Impact 2010
Sector Construction,Digital/Communication/Information Technologies (including Software),Electronics
Impact Types Economic

 
Description Pathways to impact - Frequency Selective Surfaces for Long Wavelengths
Amount £3,600 (GBP)
Funding ID EPSRC follow on funding scheme (distributed by host institution) 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2011 
End 06/2011
 
Description FSS at Aukland University, NZ and University of Kent, UK 
Organisation University of Auckland
Country New Zealand 
Sector Academic/University 
PI Contribution Kent designed FSS based on highly convoluted elements used in an office facility in the Engineering department at the University of Auckland to assess frequency dependent screening at long wavelengths. Two papers have been published. The FSS was designed and fabricated by staff at the University of Kent, despatched to Auckland and installed by technical staff there in a specially constructed screened office. Auckland's equipment characterized the frequency selective performance of the structure, the manpower including 2 Kent staff in addition to the NZ personnel. The outcomes were published in an Electronics Letter.
Collaborator Contribution In the period of this collaboration NZ staff (Williamson, Sowerby and Neve) have paid return visits to the Universities of Kent, Birmingham, Sheffield and Manchester. The Auckland partners have led authorship on several journal and conference papers with joint UK authorship, including the PI at Kent.
Impact Key outputs are journal and conference publications as listed in the project sections. Additionally, Auckland visitors have invited membership on the panel of the Wireless Friendly Buildings Forum, and have led the design of the user friendly wireless interference teaching tool mounted at: http://wfbf.eda.kent.ac.uk/
Start Year 2006
 
Description Smart Buiding Outreach talks to Kent schools 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact The talk provoked questions from interested pupils with several enquiring about further study in Engineering. One school requested a repeat of the talk for a larger audience.

One school requested a repeat of the talk for a larger audience. Another school reported that a pupil was disappointed to discover she could not continue to an Engineering degree as she had dropped maths.
Year(s) Of Engagement Activity 2007,2008,2009,2010,2011