Metamaterial slab for MRI

A metamaterial structure configured to passively interact with a field generated by a transmit device within the MRI system to improve one or more of homogeneity of the field within a scan target, specific absorption rate within the scan target, and strength of the field within the scan target when the metamaterial structure is present within a bore of the MRI system with the scan target, the metamaterial structure comprising:

• a first layer generally defining a surface and a second layer offset from the surface generally defined by the first layer, the first layer and the second layer interacting to form a 2D transmission line supporting radio frequency (RF) current along the surface in a first direction tangential to the surface and in a second direction tangential to the surface and transverse to the first direction, the first layer comprises a grid of traces, the grid comprising first traces extending in the first direction and second traces extending in the second direction, the first traces including first capacitors between the second traces and the second traces include second capacitors between the first traces, the first layer and the second layer being connected via linking capacitors, in which the linking capacitors connect to the second traces, the second traces also including inductors in series with the second capacitors.

A metamaterial structure configured to passively interact with a field generated by a transmit device within the MRI system to improve one or more of homogeneity of the field within a scan target, specific absorption rate within the scan target, and strength of the field within the scan target when the metamaterial structure is present within a bore of the MRI system with the scan target, the metamaterial structure comprising:

• a first layer generally defining a surface and a second layer offset from the surface generally defined by the first layer, the first layer and the second layer interacting to form a 2D transmission line supporting radio frequency (RF) current along the surface in a first direction tangential to the surface and in a second direction tangential to the surface and transverse to the first direction, the first layer and the second layer being connected via linking capacitors, the metamaterial structure comprising tuning elements that add or remove capacitance or inductance to alter a characteristic of the metamaterial structure, the tuning elements including inductance tuning elements arranged to tune inductances in series with the linking capacitors.