Distributed excitation of a birdcage transmitter for wireless powering of endoscopic capsules

This study deals with an innovative design of the excitation system of a birdcage transmitter for wireless powering of micro implants. The use of the birdcage coil is a very promising solution to realize an efficient transmitting system. This type of source, widely used for the magnetic resonance imaging (MRI), ensures a circularly polarized magnetic field inside the human body. One of the main issues is the excitation system of the birdcage coil as the field is highly sensitive to small variations in the coil geometry. The idea is to replace the traditional birdcage with a geometrically deformed cage that can be installed on a wearable corset, adaptable to different body shapes while maintaining electromagnetic functionality. Thus, an innovative system is presented with independent feeding for each leg of the cage. The robustness of the proposed solution is tested varying the birdcage coil geometry assuming a working frequency of 300 kHz.