# US 2021/0241961 A1 · Polyhedral coil systems having a large homogeneity volume and large access zone > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241961 A1 - Document ID: US20210241961A1 - Status: Published application - Kind: A1 - Application number: 17/049,069 - Filed: 2019-04-18 - Published: 2021-08-05 - Earliest claimed: 2018-04-20 - Assignees: Stl Systems AG - Applicants: Stl Systems AG - Inventors: Christoph Ludwig; Stefan Ludwig; Wolfgang Ludwig - Web page: https://patentgrep.com/patent/US20210241961A1 ## CPC - H01F 7/202: {Electromagnets for high magnetic field strength (for superconducting electromagnets H01F6/00; for transformers or inductances without a magnetic core H01F30/08)} - H01F 27/28: Coils; Windings; Conductive connections - G01R 33/0017: {Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields} - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A coil system (30, 40, 50) for generating a homogeneous magnetic field, includes a coil assembly (2), each assembly having at least two coils (S1, S2, S3), the respective windings (W1, W-2, W3) of which span. rotationally symmetrical faces lying plane-parallel to one another having different sizes and a common axis of rotation running perpendicularly to the faces, forming a coil axis (4), wherein a current can flow in the opposite direction through at least one of the coils (S1, S2, S3), and having at least two coil assemblies (2), wherein the coils (S1, S2, S3) of each coil assembly (2) are located within and oriented plane-parallel to the base of a generating pyramid, the tip of which coincides with the centre of a regular convex polyhedron and the base surface of which is identical to one such face of the convex polyhedron, on which the projection of the pyramid tip onto the pyramid base surface coincides with the centre of the pyramid base surface. ## Claims ### Claim 1 A coil system (30, 40, 50) for generating a homogeneous magnetic field, the coil system (30, 40, 50) comprising a coil assembly (2), each coil assembly (2) being composed of at least two coils (S1, S2, S3), the respective windings (W1, W2, W3) of said coils (S1, S2, S3) forming plane-parallel, rotationally symmetrical surfaces having different sizes and a common axis of rotation as a coil axis (4) running perpendicular to the surfaces, a current flowing in the opposite direction in relation to another one of said coils through at least one of said coils (S1, S2, S3), further comprising at least three coil assemblies (2), the coils (S1, S2, S3) of each coil assembly (2) being located inside and oriented plane-parallel to the base surface of a generating pyramid, the apex of which coincides with the center of a regular, convex polyhedron and the base surface of which is identical to a surface of the convex polyhedron in which the projection of the pyramid apex onto the pyramid base surface coincides with the center of the pyramid base surface, wherein the polyhedron is a tetrahedron, a hexahedron, an octahedron, a dodecahedron or an icosahedron which has n surfaces can be composed of n generating pyramids in a volume-filling manner. ### Claim 2 (depends on 1) The coil system according to claim 1, wherein the rotationally symmetrical surface formed by the respective windings (W1, W2, W3) of the respective coils (S1, S2, S3) is a combination of polygonal surface segments and circular surface segments. ### Claim 3 (depends on 1) The coil system according to claim 1, wherein the rotationally symmetrical surface formed by the respective windings (W1, W2, W3) of one of the coils (S1, S2, S3) is realized in a spiral shape. ### Claim 4 (depends on 1) The coil system according to claim 1, wherein a winding shape of one of the windings (W1, W2, W3) has, in sections, a component in the direction of the axis of rotation. ### Claim 5 (depends on 1) A use of the coil system (30, 40, 50) according to claim 1 in a system for calibrating magnetic field sensors and magnetic compasses, for generating and simulating magnetic conditions on satellites and space probes, for compensating magnetic fields, for reducing or neutralizing magnetic signatures on ship components, for testing and controlling the quality of permanent magnets, for measuring magnetic properties in materials research and geophysics and for generating magnetic fields and magnetic field gradients in medical technology and magnetic resonance imaging. ### Claim 6 (canceled). ### Claim 7 (depends on 2) The coil system according to claim 2, wherein the rotationally symmetrical surface formed by the respective windings (W1, W2, W3) of one of the coils (S1, S2, S3) is realized in a spiral shape. ### Claim 8 (depends on 2) The coil system according to claim 2, wherein a winding shape of one of the windings (W1, W2, W3) has, in sections, a component in the direction of the axis of rotation. ### Claim 9 (depends on 3) The coil system according to claim 3, wherein a winding shape of one of the windings (W1, W2, W3) has, in sections, a component in the direction of the axis of rotation.