Stacked Spirals for Biosensor Telemetry

This paper presents an inductive power transmission coil for biosensor-based telemetric implants. Using stacked spirals reduces the consumed space and the self-resonant frequency (SRF) of the spiral and the required power transmission frequency for the implanted device. A four-layer 15 mm X 15 mm spiral coil of seven turns is simulated in CST Microwave Studio (TM), constructed and tested in hardware with comparable results. Measurements also include the receipt of power inductively from an energized array of spirals powered by a Class-E transmitter at 27 MHz, and rectified to 1 V for biosensor applications.