Patent ID: 6927574

Claim:
Magnetic resonance apparatus, in which resonance is excited within magnetic resonant active nuclei in a region of an object in the presence of a main magnetic field, including a guide structure with magnetic properties which guides magnetic flux, wherein the guided magnetic flux is indicative of magnetic resonant active nuclei in an object under examination, the guide structure having a magnetic permeability greater than that of free space at the frequency of nuclear magnetic resonance but being non-magnetic in steady magnetic fields, the guide structure comprising an array of capacitive elements, the array exhibiting a predetermined magnetic permeability in response to incident electromagnetic radiation lying within a predetermined frequency band which includes the magnetic resonance frequency, wherein each capacitive element includes a conducting path and is such that a magnetic component of the electromagnetic radiation at the magnetic resonance frequency induces an electrical current to flow around said path and through said capacitive element, wherein the spacing between the capacitive elements is less than the wavelength of the radiation within the predetermined frequency band, and wherein the size of the capacitive elements and their spacing apart are selected in order to provide the magnetic permeability greater than that of free space at the magnetic resonance frequency.