Powering implanted sensors that monitor human activity using spider‐web coil wireless power transfer

Abstract

Implantable biomedical devices (IBMD) and biomedical sensors (BMS) enhance patients’ quality of life by monitoring vital signs, detecting diseases, and replacing malfunctioning organs. However, IBMDs and BMSs require battery power to operate, and they have limited battery life. Wireless power transfer (WPT) is one practical way to address this limitation. In this paper, the authors designed and implemented WPT‐based magnetic resonant coupling (MRC) using a spider‐web coil (SWC) (WPT–MRC–SWC) that supplies the proposed IBMD, including accelerometer sensors, the single‐chip microcontroller ATmega 328, and the nRF24L01 wireless protocol, with power. The WPT–MRC–SWC examines acceleration measurements on three knee‐joint axes (X, Y, and Z) in five different positions: sitting, standing, walking, lying down, and jogging. The SWC of transmitters and receivers (implanted) exhibits an operating frequency of 1.78 MHz with a series/parallel (S/P) configuration. The implanted system's data, transmitted outside the human body using nRF24L01, operates at 2.4 GHz. The results reveal that WPT provides 5 V at an air gap of 60 mm between the receiver and transmitter coils, indicating that it can run or charge IBMD batteries without failure. This study validates the effectiveness of the WPT–MRC–SWC by applying it to an actual application.

Optimal Frequency and Wireless Power Budget for Miniature Receivers in Obese People

“…Ultra-deep, miniature receivers: For the first time, mm sized receivers are investigated at depths up to 20 cm in the body, for the inclusion of all body types. Existing studies either focus on smaller depths, <10 cm, for deep implants [36,[40][41][42][43][44], target larger receivers [45][46][47], or include tissue only for a small part of the Tx-Rx distance [48].…”