Energy-Harvesting Coil for Circularly Polarized Fields in Magnetic Resonance Imaging

Specialized RF coils and sensors placed inside the magnetic resonance imaging (MRI) scanner considerably extend its functionality. However, since cable connected in-bore devices have several disadvantages compared to wireless ones, the latter currently undergo active development. One of the promising concepts in wireless MRI coils, energy harvesting, relies on energy carried by the RF MRI field without the need for additional transmitters as in common wireless power transfer. In this letter, we propose a compact harvesting coil design based on the combination of the loop and butterfly coils that allows energy harvesting of a circularly-polarized field. By performing numerical simulations and experiments with commonly used Siemens Espree and Avanto 1.5 Tesla MRI scanners, we have demonstrated that the proposed approach is safe, efficient, does not decrease the quality of MRI images, and allows doubling the harvested voltage in contrast with linearly polarized setup.