Modulated Backscatter for Ultra-Low Power Uplinks From Wearable and Implantable Devices
Wearable and implantable wireless biomedical devices are often constrained by the limited bandwidth and high power consumption of their communication links. The VHF or UHF transceivers (e.g. MICS radios) traditionally used for this communication function have relatively high power consumption, on the order of mW, due to the high bias currents required for the analog sections of the radio. To reduce over-all power consumption, both the data rate and the duty cycle of the radio are usually minimized, because the lifetime of the device is limited by the energy density of available battery technologies. Recent innovations in modulated backscatter techniques offer the possibility of a radical reduction in the power cost and complexity of the data uplink, while significantly improving data rate.