Reporter 435, 26 April 1999

Microwave chips to put phone masts in the past

A tiny chip developed at Leeds is set to transform the British landscape, by making redundant tens of thousands of mobile phone masts in our countryside and cities.

Award-winning research in electrical and electronic engineering to develop replacements the size of cigarette packets will allow the transmitters - viewed by many as an eyesore - to be torn down.

The new equipment will also help reduce some of the public anxiety about the safety of powerful transmitter aerials. The reduced power of the new units means the little radiation they produce does not travel far and is easily blocked.

The research is based on a tiny 'microwave mixer' electronic chip developed by research assistant Michael Roberts. The team believes its size - about the same as a match head - could revolutionise mobile phone operations. "All the equipment necessary to receive and transmit a signal could be included in a box the size of a cigarette packet," said Mr Roberts.

"These could then be attached to lamposts, the sides of buildings or the underside of bridges. This would remove the need for bulky antennae and ensure a good signal could be received virtually everywhere." The team estimates the boxes could be produced for less than £100 each. Project leader Stavros Iezekiel believes a prototype system could be finished within a year.

The chip allows low frequency signals - such as a person's voice - to 'piggy-back' on much higher electronic frequencies. These faster signals can travel through the air without being distorted, allowing a receiver up to a kilometre away to then decode the original message.

Current systems send slower signals so require larger, more powerful transmitters to send an accurate message over the same distance. The much higher frequency signals also create more space on the crowded airwaves.

Postgraduate research student Neil Bourhill is developing a vital intermediate stage in which the electronic signal is sent down optical fibre to the mixer chip. His research was recently judged among the country's best at a UMIST postgraduate conference.

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