This research is part of the nanotera.ch project Intelligent Integrated Systems for Personalized Medicine (ISyPeM).
|A Biotelemetry System|
|Multiband Concurrent R Front End for “on-body” patch|
The goal of this research work is to design and integrate a wireless interface for biomedical applications like personalized wireless drug delivery systems. This work shall focus mainly on the “on-body” patch which acts like a gateway between the monitoring unit and the implants which are outside and inside the patient’s body respectively. So, a multiband transceiver is needed to accomplish this task. The transceiver should be able to communicate with the monitoring unit on Bluetooth ULP (Ultra Low Power) at 2.4 GHz and similarly with the implants at 405 MHz on MICS (Medical Implant Communication Services) band. The patch will also host an energy harvesting unit to charge its battery from the power radiated from a NFC (Near Field Communication) featured mobile device. This calls the need for a power management unit which should be able to rectify the inductively coupled power at 13.56 MHz and charge up a battery or a super capacitor and thus avoiding frequent replacement of batteries.
Based on the required constraints, a sampling based approach for the receiver on the the on-body patch has been proposed. The novelty in this approach is the use of a single sampling clock to downconvert both the bands- Bluetooth LE and MICS to baseband. Bluetooth LE signal gets directly downconverted to baseband while the MICS signal gets first downconverted to half the sampling rate and this is again sampled to bring it down to baseband. The second stage of sampling provides the required lowpass(Bluetooth) or bandpass (MICS) characteristics as required in the corresponding paths. The sampling clock used in this second stage is a simple integer divided version of the initial sampling rate. The architecture proposed has been simulated and validated and a relative attenuation of around 42 dB is achieved between the down converted version of both the bands.