Miniature and Multi-Band RF Coil Design

• US 20100090824A1
• Filed: 10/14/2008
• Published: 04/15/2010
• Est. Priority Date: 10/14/2008
• Status: Active Grant

• Current Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: Lai, Hau-Wah, Rowell, Corbett R., Mak, Chi-Lun
• Granted Patent: US 8,056,819 B2
• Time in Patent Office: Days
• US Class Current: 340/539.11
• CPC Class Codes: 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
• CPC Class Codes: G01R 33/34046 Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/34061 Helmholtz coils
• CPC Class Codes: G01R 33/341 comprising surface coils
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/06 Arrays of individually energised antenna units similarly polarised and spaced apart
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

A near field apparatus comprises a Radio Frequency (RF) coil including at least one of a shorting bridge from a first point to a second point along an electrical path of the RF coil and/or a discontinuity in the electrical path of the RF coil.

Claims

1. A near field apparatus comprising:

a Radio Frequency (RF) coil including at least one item selected from the list consisting of;

a shorting bridge from a first point to a second point along an electrical path of the RF coil; and

a discontinuity in the electrical path of the RF coil.

2. The near field apparatus of claim 1 further comprising:

a transmission line input and output to the RF coil.

3. The near field apparatus of claim 2, wherein the RF coil includes both the shorting bridge and the discontinuity matching an impedance with the transmission line input and output.

4. The near field apparatus of claim 1 further comprising:

an RF transmitting module supplying RF energy to the RF coil via the transmission line input and output, the RF transmitting module configured to provide RF energy at a frequency that produces near field energy at the RF coil.

5. The near field apparatus of claim 1 further comprising:

a plurality of other RF coils forming an array.

6. The near field apparatus of claim 1 wherein the RF coil comprises a double-layer spiral type coil on a Printed Circuit Board (PCB) substrate.

7. The near field apparatus of claim 1 wherein the RF coil comprises a double-layer spiral type coil on a flexible substrate.

8. The near field apparatus of claim 1 wherein the RF coil comprises a helical coil.

9. The near field apparatus of claim 1 comprising one or more of the following items selected from the list consisting of:

a Radio Frequency Identification (RFID) device;

a Near Field Communications (NFC) device; and

an MRI device.

10. A method for creating a Radio Frequency (RF) coil that includes one or more of a shorting bridge within its current path and a current path discontinuity to provide a selected operating frequency and impedance, said method comprising:

determining the placement of the one or more of a current path discontinuity and a shorting bridge by performing one or more actions selected from the list consisting of;

creating one or more computer simulations of the RF coil to arrive at a placement of the one or more of a current path discontinuity and a shorting bridge that satisfies the selected operating frequency and the selected impedance; and

creating and testing one or more prototypes of the RF coil to arrive at a placement of the one or more of a current path discontinuity and a shorting bridge that satisfies the selected operating frequency and the selected impedance.

11. The method of claim 10 further comprising:

manufacturing the RF coil with the one or more of the current path discontinuity and the shorting bridge configured according to the determined placement.

12. The method of claim 11 further comprising:

disposing the RF coil in a near field application.

13. The method of claim 12 wherein the near field application comprises an MRI machine.

14. The method of claim 12 wherein the near field application comprises an RFID tag.

15. The method of claim 12 wherein the near field application comprises an RFID reader.

16. The method of claim 12 wherein the near field application comprises an NFC transmitter.

17. The method of claim 12 wherein the near field application comprises an NFC reader.

18. A Radio Frequency Identification (RFID) device comprising:

a miniaturized Radio Frequency (RF) coil that includes a current path with a shorting bridge and a discontinuity in the current path providing impedance matching and frequency shifting for the RF coil; and

supporting circuitry in the RFID device facilitating one or both of transmission and detection of RF energy by the coil.

19. The RFID device of claim 18 comprising:

a Near Field Communication (NFC) device.

20. The RFID device of claim 19 comprising:

a cellular phone.

21. The RFID device of claim 18 comprising:

a Radio Frequency Identification (RFID) tag.

22. The RFID device of claim 21 wherein the RF coil comprises a double-layer spiral type coil on a flexible substrate.

23. The RFID device of claim 18 the RF coil comprises a double-layer spiral type coil on a Printed Circuit Board (PCB) substrate.

24. A Magnetic Resonance Imaging (MRI) apparatus comprising:

a Radio Frequency (RF) coil that includes a current path with a shorting bridge and a discontinuity in the current path providing impedance matching and frequency shifting for the RF coil; and

supporting circuitry in the MRI machine facilitating one or both of transmission and detection of RF energy by the coil.

25. The MRI apparatus of claim 24 wherein the RF coil comprises a helical coil.

26. The MRI apparatus of claim 24 further comprising:

a plurality of other RF coils forming an array with the RF coil.

27. The MRI apparatus of claim 24 wherein the RF coil comprises a helical coil adapted to accommodate a human body part therein.