An analysis of the birdcage resonators using magnetic field probes, for validation of optimal aspect ratio

Abstract

Two probes were created in order to analyse the magnetic field of the birdcage resonators with different heights and aspect ratios. The first probe has a larger pickup loop at its end and was shielded to reduce the electric field coupling. The second probe with a smaller loop was not shielded at its end. The relative values of magnetic field intensity obtained using the two probes were similar, however, the first probe has better sensitivity. Both measurements confirm that there exists an optimal height and, therefore, an aspect ratio, of the resonators with respect to the generated magnetic field intensity.