20130200897 | METAMATERIAL LINERS FOR HIGH-FIELD-STRENGTH TRAVELING-WAVE MAGNETIC RESONANCE IMAGING - A liner for a bore of a waveguide is provided. The liner as an aperture passing through it and is formed of a metamaterial that has a relative electrical permittivity that is negative and near zero. When the liner is installed in the waveguide, it lowers the cutoff frequency of the waveguide while allowing the waveguide to remain hollow. This liner can be used in the bore of an MRI machine to lower the cutoff frequency of the bore of the MRI machine to allow the MRI machine to operate using waves having a lower frequency that if the liner was not used. | 08-08-2013 |