Multi-layer resonator for magnetic resonance applications with circuitry allowing equal magnitude current during active operation
A resonator for magnetic resonance applications has a conductor element that extends from a first conductor end to a second conductor end. During operation of the conductor element at a resonance frequency, a resonance current-oscillates from the first conductor end to the second conductor end and back. The conductor ends are coupled with one another via a circuit that tunes the conductor element to the resonance frequency. The conductor element is fashioned as a multi-layer conductor with a number of layers that have first and second layer ends at the conductor ends. The circuit causes layer currents that are of equal magnitudes to flow in the layers themselves during active operation of the conductor element at the resonance frequency.
1. A resonator configured for magnetic resonance applications comprising:
a conductor element extending from a first conductor end to a second conductor end, said conductor element comprising a multi-layer conductor having a plurality of layers, which respectively have layer ends at said first and second conductor ends; and
a circuit electrically coupled to said first and second conductor ends that tunes said conductor element to a resonance frequency, said conductor element, at said resonance frequency, having a resonance current therein that oscillates from said first conductor end to said second conductor end and back to said first conductor end, said circuit causing respective layer currents of respectively equal magnitudes to flow in the respective layers of the multi-layer conductor during active operation of said conductor element at said resonance frequency.
2. A resonator as claimed in claim 1 wherein said circuit directly couples said first and second conductor ends with one another.
3. A resonator as claimed in claim 1 wherein said circuit couples said first and second conductor ends with one another through a ground area.
4. A resonator as claimed in claim 1 wherein said circuit interconnects said first and second layer ends with one another so that said layers are connected with one another in series.
5. A resonator as claimed in claim 4 wherein said plurality of layers include a first layer, as viewed in a current flow direction of said resonance current, and a last layer, as viewed in said current flow direction of said resonance current, and wherein said circuit comprises an electrical component between said first layer and said second layer so that said first layer and said second layer are not connected in series with one another.
6. A resonator as claimed in claim 4 wherein said plurality of layers include a first layer, as viewed in a current flow direction of said resonance current, and a last layer, as viewed in said current flow direction of said resonance current, and wherein said circuit comprises a capacitor connected between said first layer and said second layer that connects said first layer and said second layer in series with one another.
7. A resonator as claimed in claim 6 wherein said capacitor is a first capacitor, and comprising a second capacitor connected in series with said first capacitor, with at least one of said plurality of layers being connected between the first capacitor and the second capacitor as viewed in said current flow direction of said resonance current.
8. A resonator as claimed in claim 1 wherein said circuit interconnects the respective layer ends with one another to connect said plurality of layers in parallel with one another, and wherein said circuit comprises, for each layer in said plurality of layers, an impedance adaption circuit individually associated with that layer and directly electrically connected to one layer end of the layer individually associated with the impedance adaption circuit.
9. A resonator as claimed in claim 8 wherein each impedance adaption circuit comprises at least one of a capacitor and a coil.
10. A resonator as claimed in claim 8 wherein each impedance adaption circuit is directly connected with both layer ends of the layer individually associated with the impedance adaption circuit.
11. A resonator as claimed in claim 10 wherein each impedance adaption circuit is connected to one of the layer ends of the layer individually associated with the impedance adaption circuit via a connection region that is common to all of said impedance adaption circuits.
12. A resonator as claimed in claim 1 wherein said circuit comprises a residual circuit connected in said common connection region.
13. A resonator as claimed in claim 12 wherein said residual circuit comprises at least one of a capacitor and a coil.
14. A resonator as claimed in claim 1 wherein each of said layers in said plurality of layers comprises a plurality of strips, and wherein said circuit, during operation of said conductor element at said resonance frequency, causes respective strip currents to flow in the strips that are of equal magnitude with each other within the layer formed by the respective strips.
15. A resonator as claimed in claim 14 wherein said strips are comprised of strip material having a skin depth at said resonance frequency, and wherein said strips each have a strip width that is larger than said skin depth of said material at said resonance frequency.