Coupling loop and method for positioning coupling loop

• US 20060244465A1
• Filed: 06/30/2006
• Published: 11/02/2006
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: St. Jude Medical Luxembourg Holdings Ii S.A.R.L.
• Original Assignee: CardioMEMS Incorporated
• Inventors: Ellis, Michael, Miller, Donald, Kroh, Jason
• Granted Patent: US 7,432,723 B2
• Time in Patent Office: Days
• US Class Current: 324/654
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02014 Determining aneurysm
• CPC Class Codes: A61B 5/064 using markers A61B5/062 takes precedence
• CPC Class Codes: A61B 5/07 Endoradiosondes
• CPC Class Codes: H01B 11/20 Cables having a multiplicity of coaxial lines
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A coupling loop or antenna is provided that can be used with a system that determines the resonant frequency of a sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The coupling loop includes multiple loops. Preferably two tuned loops are used for transmitting the energizing signal to the sensor and an un-tuned loop is used for receiving the sensor signal from the sensor. Orientation features on the housing for the coupling loop and the sensor are provided to assist in positioning the coupling loop relative to the sensor to maximize the coupling between the sensor signal and the coupling loop.

Claims

1. A coupling loop assembly used for wireless communication, comprising:

a sensor coupling loop having an inductance and connected to an input having an input impedance, wherein the input impedance is at least two times greater than the inductance of the sensor coupling loop; and

a plurality of energizing loops arranged in parallel, each energizing loop having a different resonant frequency.

2. The loop assembly of claim 1, wherein the sensor coupling loop is parallel to the energizing loops and the energizing loops surround the sensor coupling loop.

3. The loop assembly of claim 1, wherein the resonant frequency for a first energizing loop is approximately 31 MHz and the resonant frequency for a second energizing loop is approximately 36.3 MHz.

4. A loop assembly used for wireless communication, comprising:

a plurality of sensor coupling loops, each coupling loop having a different resonant frequency; and

a plurality of energizing loops, each energizing loop having a different resonant frequency.

5. The loop assembly of claim 4, wherein the sensor coupling loops and the energizing loops are parallel to each other and the energizing loops surround the coupling loops.

6. A method of wireless communication using a loop assembly, comprising:

providing an energizing signal using a plurality of tuned loops, wherein each tuned loop has a distinct resonant frequency; and

receiving a coupled signal using an un-tuned loop connected to an input impedance that is at least two times greater than an impedance of the un-tuned loop, wherein the coupled signal is generated in response to coupling the energizing signal to a signal generating circuit, is at least 100 dB less than the energizing signal, and has a frequency similar to a frequency of the energizing signal.

7. The method of claim 6, wherein the resonant frequencies of the tuned loops are selected based on a mean frequency of a desired bandwidth.

8. The method of claim 6, wherein the coupled signal is sampled less than 50 nanoseconds after the energizing signal is provided.

9. A method of positioning a coupling loop relative to a sensor, comprising:

positioning the coupling loop relative to the sensor so that a first area of a housing for the coupling loop is in a predetermined position with respect to the sensor; and

adjusting an angle of the coupling loop relative to the sensor until a predefined pattern is formed by markings on the sensor and markings on the housing,

wherein a medical imaging technology is used for positioning the coupling loop and adjusting the angle of the coupling loop.

10. The method of claim 9, wherein the sensor includes a flat side and an inductor parallel to the flat side and wherein the predefined pattern is formed when a plane formed by the coupling loop is approximately parallel to the flat side of the sensor.

11. The method of claim 9, wherein the predefined pattern is selected from the group consisting of:

a bulls eye, a cross hair, a cross, a logo, an image, and an alphanumeric string.

12. The method of claim 9, wherein the first area of the housing is approximately at a center of a receive loop within the housing.

13. A coupling loop, comprising:

a sensor coupling loop for receiving a signal from a sensor; and

a housing surrounding the sensor coupling loop and having a first area that is approximately at the center of the sensor coupling loop, wherein the first area includes an orientation mark that is visible using a medical imaging technology and is used to position the coupling loop relative to the sensor.

14. The coupling loop of claim 13, wherein the orientation mark is formed from support ribbing inside the housing.

15. The coupling loop of claim 13, wherein the first area is co-planar with a plane extending through the sensor coupling loop.

16. The method of claim 13, wherein the orientation mark is selected from the group consisting of:

a circle, a bulls eye, a cross hair, a cross, a logo, an image and an alphanumeric string.

17. The method of claim 13, wherein the orientation mark comprises a plurality of marks that indicate a length or a distance.