Q5 interview - Alistair Morfey, Cambridge Consultants
Cambridge Consultants has developed antenna technology for medical implants. Unlike magnetically-coupled antennas, these communicate without a receiver against the skin.
"Most communication with implants works only over a few inches, or a foot," Cambridge Consultants v-p Ian Mawhinney told Electronics Weekly. "This is not a problem with pacemakers that only occasionally get read, but now people are looking for something that collect data from a patient at home and sends it back to a physician.
The aim, for example, would be to have a transceiver that can communicate with an implant wherever the patient is in the home.
"We have recorded 500kbit/s over in excess of 5m," said Mawhinney. "we haven't tested the maximum, but it could be up to 30m."
To get the range, the antenna produces a radiating electromagnetic field. "It can work from beneath a fat layer, from 2cm to maybe 10cm in a obese person," said Mawhinney.
The firm is not describing the technology in detail. Mawhinney described it as: "not a patch, but more of a patch than a loop."
Last year in a paper, Cambridge Consultants described a related implantable antenna consisting of a loop within a dielectric capsule.
Immediately near the loop, peak E-fields are high, so the dielectric is sized to allow E-fields to settle before they enter the lossy body tissue.
The firm claims to have demonstrated a seven-fold improvement in antenna power consumption. "Implant batteries may last for seven years or so. An efficient antenna can extend this by a year," said Mawhinney.
Although Cambridge Consultants is based in the UK, the firm's Implantable Antenna Laboratory is in Cambridge Massachusetts.
It is developing 2.45GHz or 402-406MHz implant antennas to order, mostly designed to work with Zarlink's MICS (Medical Implant Communication Service) transceiver.
Initially used in pacemakers, electronics are now found in implants for: neurostimulation, bio-sensing, and drug delivery, said Mawhinney.
See also: Q5 interview - Alistair Morfey, Cambridge Consultants