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Transceiver on a chip
The one-chip radio transceiver - an idea first popularised
in Dick Tracy comics as the wristwatch two-way radio - will
soon be a commercial reality, thanks to RF researchers in
the United States.
They've made it possible by miniaturising a waveguide slot
antenna for the 2400 MHz band and replacing the bulky quartz crystal with
a micro miniature resonator disc just 64
millionths of a metre (64 microns) in diameter.
The antenna is made from a spiral slot etched into the top
metal layer of the transceiver integrated circuit. It's only
one square centimetre in area. The researchers eliminated
matching components by tailoring the antenna's shape.
The resonator that replaces a quartz crystal is even more
cunning. It works in the same way that you make a wine glass "ring"
by flicking the lip with your finger.
The on-chip resonator disc is set ringing at 60 MHz by a
tiny
micro-electro-mechanical system (MEMS) device that flicks
it, while an integral amplifier sustains oscillations.
It achieves stability and purity comparable to a crystal
oscillator, the Michigan University researchers claim.
The researchers, who are already talking with chip giant
Intel, expect the technology to be applied in hearing-aid
sized cellphones, laptop computers, environmental sensors
and - yes - wristwatch two-way radios!
(Thanks to both VK1KEP and VK2ZRH)
Source: Wireless
Institute of Australia
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