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Surface Acoustic Waves (SAW)
The devices you have never heard about.
Lord Rayleigh first described the theory of SAW in 1885 with regard to earthquakes, but it was not until 1965 that the theory started to become a practical proposition for use in electronics with advances in photolithography and metal evaporation onto quartz substrates. They had the potential to revolutionise many electronic components and enable complex systems to be miniaturised with enhanced performance. The reduction in size was massive for many pre-SAW components, enabling new applications to be developed.
The attractions of SAW devices were that they were small, cheap to make, reproducible, rugged and no power supply was needed with the advantage of an extremely flexible design capability.
Ministry of Defence applications of SAW devices in 1985
Internal RSRE applications of SAW devices
- Ray Cyphus Cambs sonobuoy oscillator
- Dennis Maines operational requirement 1972
- John Clarke radar dispersers
- On-site NATO IFF transmit and receive oscillators
- D Colliver operational requirement 1973
- Bill Richmond rifle bullet tracking
- Sid Widdows experimental radar
- Colin Boyne set on jammer
- Roy Pike spectrum analyser
- John Hinsley, convolvers, filterbank and tapped delay line
- Dick Harris convolvers from Edinburgh university
All this work led to a Queen’s award
In the 1990’s, RSRE SAW inventions & patents were licenced to Japanese, Chinese & German companies. Some commercial uses of SAW devices were Fibre Optic clock recovery filters, Hewlett Packard test equipment, keyless entry, e.g. garage door openers, British Rail railway carriage tracking, Analogue TV filters, Distress oscillators, Transmitting sensors in rotating machinery, eg jet engines, Tyre pressure sensors, Gas/pollution detectors, Radio astronomy (ATACAMA Desert large array distributed receivers) and Space applications. The largest and most widely distributed use is in the billions and billions of mobile phones in use today.
Based on a lecture given by Meirion Lewis