12-03-2012, 02:15 PM
Powering and Communicating with mm-size implants
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Power sources for implants
Electromagnetic power transfer
10 to 1000 μW/sq.mm
EM field radiated by transmitter in vitro.
Antenna in vivo receives EM energy.
Rectifier & regulator produce DC voltage.
Electromagnetic Power Transfer
Antenna
Size considerations.
Optimum frequency.
Safety consideration-
SAR-Specific Absorption Rate
A measure of the rate at which energy is absorbed by the body when exposed to a radio frequency (RF) electromagnetic field .
1.6W/kg averaged over 1g of tissue.
Advantages.
More power density-10 to 1000 μW/sq.mm.
No moving parts.
No chemical processing.
Less size.
CMOS rectifier-more efficient.
