Magnetic Communication and Wireless Power Transfer using a Non-coupling Coil Array

Abstract

Magnetic field based wireless technologies can provide better performance in high permittivity channels, which are harsh environments for conventional electromagnetic (EM) based wireless transmission. Despite this benefit, they cannot be used in many applications because of critical issues such as low data rate, short transmission range, and performance degradation due to misalignment. To mitigate these problems, there are various approaches for both communication and wireless power transfer (WPT). Among them, some of the most promising are based on a coil array. Unfortunately, conventional coil arrays may cause performance degradation due to interference, as well as power leakage and phase distortion due to strong coupling between array components. Many researchers have presented non-coupling methods to mitigate these problems, however, they are typically unable to support enough independent channels. This paper presents a scalable non-coupling coil array and possible methods of using the proposed coil array for high data rate, long transmission range, and misalignment compensation. To increase the data rate, we offer a magnetic multi-input multi-output (MIMO) scheme using the non-coupling coil array. The proposed non-coupling coil based magnetic MIMO can achieve higher channel capacity with low complexity and with lower signal to interference and noise power ratio than conventional magnetic MIMO techniques that use coupled coil arrays, which have significant interference. This paper also validates the use of the non-coupling coil array with a beamforming technique to address two issues: shot transmission range and power transfer efficiency (PTE) drop due to the misalignment. The proposed magnetic beamforming can achieve longer range transmission and robust performance irrespective of the misalignment with lower-complexity than conventional magnetic beamforming, which has power leakage and phase distortion due to the strong coupling between array components. We also present an investigation of a MIMO WPT which will be applied in future works for magnetic beamforming for multiple receivers and magnetic simultaneous wireless information and power transfer.