Engineers investigate wireless architecture improvements

Modern buildings such as shopping centres, hotels, airports and exhibition centres are increasingly reliant on a range of wireless communications, with not only mobiles phones and wi-fi but RFID tagging, EDGE, Bluetooth and wireless CCTV.

However, architects are now obliged to include more metal within structures for things such as insulating foil and metallic-based tinting in heat-reflective windows.

This can create problems with interference of wireless communications, as Dr John Batchelor of Kent told The Engineer.

‘You see this all the time — we had an extension done where new insulation went in and now the radio in the kitchen won’t work anymore,’ he said.

‘You have architecture for structural and aesthetic reasons and for thermal insulation and energy conservation, but also we ought to think about wireless architecture as well, because more and more people are dependent on it.’ 

Batchelor also pointed out that the electromagnetic spectrum is a ‘finite resource’ that calls for frequency re-use in increasingly localised regions in the built environment.

It therefore becomes desirable to separate frequencies and better control wireless signals, by choosing to allow the passage of some signals through structures or reflecting others away.

For this, the researchers turned to frequency selective surfaces (FSS) which were originally developed for use in satellite sub-reflectors.

‘They are sheets of etched metallic structures that basically resonate at a certain frequency or frequencies and when they resonate they essentially filter radio signals,’ Batchelor explained.

The team are currently experimenting with various sizes and placements of FSS using simulations and scale models. They are also integrating FSS into insulating foils, wallpaper and even textiles, in an attempt to make it easy and cheap to adopt for the construction industry.

‘This is just as bespoke as the architecture of the rest of the building — how many windows you need, how many sustaining walls, how thick they are. It would have to become a part of how buildings are specified in the future, so where should these [FSS] go to make the buildings wireless friendly.’

Prof Ted Parker, also at Kent, is co-leading the project, which is part funded by the EPSRC and the Defence Science and Technology Laboratory.