Layers or coats of materials with high dielectric constant or permittivity with very low conductivity are inserted in between radiofrequency (RF) coil or coil's conductive elements and the sample to enhance the signal to noise ratio (SNR), improve image contrast, and reduce the specific absorption rate (SAR) of magnetic resonance imaging or magnetic resonance spectroscopy instruments. The embodiments of the present invention can be used as an auxiliary device to the standard pre-constructed RF coils or incorporated with RF coil constructions for enhancing RF coil performances in both transmission and reception.
