Wireless biomedical telemetry using a fully-passive brain implant

Wireless biomedical telemetry between a fully-passive brain implant and an exterior interrogator is presented. A key aspect of the proposed implant is minimization of losses to wirelessly record neurological signals as low as 50 μV
_pp
for the first time. To achieve this, we employed an implanted patch with a novel mixed architecture, and an interrogator spiral antenna. All components were integrated and optimized to achieve |S
₂₁
| ≈ -26 dB and -19 dB at 2.4 GHz and 4.8 GHz, respectively. Measurement results are presented in good agreement with simulations.