Additively Manufactured Receiver Design for Wirelessly-Powered Biomedical Applications

This paper presents a miniaturized receiver prototype fabricated using an additive manufacturing electronics process. We aim to demonstrate the feasibility and advantages of using additive manufacturing for embedding the essential components of an inductive link in a compact form factor for miniaturized biomedical devices. We demonstrated various geometries of planar and helical coils, with average diameters of 20 mm. The wireless power transfer system comprises a class-E power amplifier operating at 6.78 MHz, a 10 µH transmitter coil, and a full-wave active rectifier fabricated in TSMC 180 nm CMOS process technology. The power delivered to a 500 Ω load at the output of the active rectifier varies from 2.7 mW to 42 mW for planar coils and 3 mW to 45 mW for helical coils, over a range of 1 cm to 4 cm. The transmitter’s power consumption is kept constant at 1.25 W throughout the experiments. Furthermore, in the case of helical coils, a lateral center-to-center misalignment of 1 cm at a distance of 2 cm between the receiver and transmitter results in a 10 mW drop in the output power.