# US 2014/0197832 A1 · Antenna and antenna arrangement for magnetic resonance applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197832 A1 - Document ID: US20140197832A1 - Status: Published application - Kind: A1 - Application number: 14/234,177 - Filed: 2011-07-22 - Published: 2014-07-17 - Earliest claimed: 2011-07-22 - Assignees: Max-Planck-Gesellschaft Zur Foerderung der Wisse- nschaften e.V. - Inventors: Wolfgang DRIESEL; Toralf MILDNER; Andreas SCHAEFER; Harald MOELLER - Web page: https://patentgrep.com/patent/US20140197832A1 ## CPC - G01R 33/36: Electrical details, e.g. matching or coupling of the coil to the receiver - G01R 33/34007: {Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system} - G01R 33/3415: comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} - G01R 33/422: of the radio frequency field - H01Q 7/005: {with variable reactance for tuning the antenna} - H01Q 7/04: Screened antennas (H01Q7/02, H01Q7/06 take precedence) - G01R 33/3628: {Tuning/matching of the transmit/receive coil} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract An antenna (100), which is designed for exciting and/or detecting a magnetic resonance in an object (1) under investigation, comprises a conductor loop (10) with an inner conductor (11) and a primary shield conductor (12), which form at least one waveguide, wherein the primary shield conductor (12) is interrupted by a gap (13), and wherein a secondary shield conductor (14) is provided which surrounds the primary shield conductor (12), wherein a dielectric (15) is arranged between the primary shield conductor (12) and the secondary shield conductor (14) and at least the gap is covered by the secondary shield conductor (14). An antenna arrangement which comprises a plurality of such antennas, a magnetic resonance device, and a method for magnetic resonance imaging or magnetic resonance spectroscopy are also described. ## Claims ### Claim 1 An antenna, which is adapted for at least one of exciting and detecting a magnetic resonance in an object to be examined, comprising: a conductor loop with an inner conductor and a primary shielding conductor that form at least one waveguide, wherein the primary shielding conductor is interrupted by a gap, and a secondary shielding conductor, which surrounds the primary shielding conductor, wherein a dielectric is arranged between the primary shielding conductor and the secondary shielding conductor and at least the gap is covered by the secondary shielding conductor. ### Claim 2 (depends on 1) The antenna according to claim 1, wherein the primary shielding conductor is interrupted by several gaps, and the secondary shielding conductor covers at least one of the gaps. ### Claim 3 (depends on 1) The antenna according to claim 1, including at least one of the features the secondary shielding conductor is arranged symmetrically along a circumferential direction of the conductor loop with respect to the gap, the secondary shielding conductor surrounds the at least one waveguide fully or has a slit along the circumferential direction of the conductor loop, and the secondary shielding conductor has a sleeve-, network- or spiral shape. ### Claim 4 (depends on 1) The antenna according to claim 1, wherein the secondary shielding conductor is connected via at least one of at least one capacitance, at least one inductance and at least one diode with the primary shielding conductor. ### Claim 5 (depends on 1) The antenna according to claim 1, including at least one of the features the conductor loop has a circular, elliptic or polygon shape, and the conductor loop has a shape according to the numeral eight or half-digit multiplier of the shape according to the numeral eight. ### Claim 6 (depends on 5) The antenna according to claim 5, wherein the conductor loop has a rectangular shape. ### Claim 7 (depends on 1) The antenna according to claim 1, wherein the secondary shielding conductor has along a circumferential direction of the conductor loop a length, which is at least triple a width of the gap. ### Claim 8 (depends on 7) The antenna according to claim 7, wherein a length of the secondary shielding conductor is variable. ### Claim 9 (depends on 8) The antenna according to claim 8, wherein the secondary shielding conductor comprises at least two shielding sections that are connected in an electrically conductive manner and are shiftable relative to one another. ### Claim 10 (depends on 1) The antenna according to claim 1, including at least one of the features the dielectric has a thickness of at least 10 μm, and the dielectric is formed by at least one insulator. ### Claim 11 (depends on 1) The antenna according to claim 1, which comprises at least one of: a tuning device which is arranged for tuning the antenna to at least one Larmor frequency, a switching device by use of which a sensitivity of the antenna or an arrangement of a plurality of the antenna can be varied, and a change-over switch, which is adapted for connecting the antenna with a receiver or a transmitter of a magnetic resonance device. ### Claim 12 (depends on 11) The antenna as claimed in claim 11, wherein the switching device has PIN diodes. ### Claim 13 (depends on 1) The antenna according to claim 1, which is formed exclusively as a sending antenna. ### Claim 14 (depends on 1) The antenna according to claim 1, which is formed exclusively as a receiving antenna. ### Claim 15 (depends on 1) An antenna arrangement which comprises a plurality of antennas according to claim 1. ### Claim 16 (depends on 15) The antenna arrangement according to claim 15, in which the antennas are arranged such that at least two conductor loops are overlapping, adjacent to each other, or are at a distance from each other. ### Claim 17 (depends on 15) The antenna arrangement according to claim 15, wherein the conductor loops have at least one of different shapes and different sizes. ### Claim 18 (depends on 15) The antenna arrangement according to claim 15, wherein the antennas are arranged in such a way that the conductor loops extend along a curved reference surface. ### Claim 19 (depends on 15) The antenna arrangement according to claim 15, wherein the antennas form an antenna stack. ### Claim 20 (depends on 1) A magnetic resonance device, which is adapted to generate a static magnetic field with a predetermined magnetic field direction and at least one antenna according to claim 1. ### Claim 21 (depends on 20) The magnetic resonance device according to claim 20, wherein the at least one antenna is arranged in such a manner that a direction of maximum sensitivity of the antenna is vertical or inclined relative to the magnetic field direction. ### Claim 22 (depends on 1) A method for magnetic resonance imaging or magnetic resonance spectroscopy, including the steps of: at least one of exciting and detecting a magnetic resonance in an object, which is to be examined, with an antenna according to claim 1. ### Claim 23 (depends on 22) The method according to claim 22, wherein the antenna is used: (a) as a transmitting antenna, a receiving antenna or a transmitting-receiving antenna or in alternating operation, or (b) for a transmission-side or reception side parallel imaging technique or a combination of both (a) and (b). ### Claim 24 (depends on 22) The method according to claim 22, wherein the antenna is tuned by at least one of setting a length of the secondary shielding conductor along a circumferential direction of the conductor loop and adjusting a capacitive or inductive coupling of the secondary shielding conductor with the primary shielding conductor to a predefined Larmor frequency. ### Claim 25 (depends on 1) The antenna according to claim 1, wherein the conductor loop comprises a coaxial cable, the ends of which form the feed points of the antenna, wherein the primary shielding conductor carries an insulator layer, which forms the dielectric, and the secondary shielding conductor comprises an electrically conductive coating on the insulator layer. ### Claim 26 (depends on 10) The antenna according to claim 10, wherein the dielectric has a thickness of at least 50 μm. ### Claim 27 (depends on 10) The antenna according to claim 10, wherein the insulator comprises at least one member selected from the group consisting of hydrophobic plastics, a metal oxide, a gas, a ceramic, a glass, a mineral and a vacuum. ### Claim 28 (depends on 27) The antenna according to claim 27, wherein the hydrophobic plastics comprise at least one of a polyolefin, polytetrafluoroethylene and phenolic resins.