Queen's Belfast: Wireless body sensors to monitor disease

Development opportunity

Researchers at Queen’s University, Belfast, UK, have developed wireless antennas for use in compact body sensors for monitoring disease progression and injuries remotely.

The use of biosensors attached to the body for health monitoring is not new. But the antennas that enable such devices to be linked together without wires are currently are big and uncomfortable to wear for a long time. While it is possible to reduced their size, this leads to the antennas being less efficient, meaning that the battery has to be recharged more frequently.

The researchers have developed new types of antennae that get round these limitations by harnessing the so-called “creeping wave” effect. With a conventional antenna most of the signal is transmitted either away from the patient or inwards, where it is absorbed by the body, weakening the signal. The rest of the signal, though, hugs the skin’s surface and “creep” round the body where it is picked up by the control unit.

But only a small amount of the signal “creeps” in this way and so its overall strength has to be increased to allow enough of it to reach the control unit. Although traditional antenna designs can be used, they are large and typically protrude up to 4 centimetres from the body surface.

The new antennas are designed to accentuate the creeping wave effect by maximising the amount of signal radiated out to the antenna’s side, rather than inwards and outwards. They are up to 50 times as efficient as current designs of the same dimensions. The researchers have succeeded in reducing the thickness of the antenna from 34 millimetres to less than 5 millimetres for a patch antenna.

This means antennas can be fitted almost anywhere without causing significant inconvenience. They are sufficiently low-profile to be incorporated into clothing or worn as part of a wound dressing. One design is now the subject of a patent application, with more anticipated.