Radio frequency sensor systems, electromagnetic sensor arrays, and methods of manufacture

• US 7,705,591 B2
• Filed: 06/29/2007
• Issued: 04/27/2010
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Miller, Robert J., Geren, William P.
• Primary Examiner(s): LeDynh; Bot L
• Application Number:
  US11/772,004
• Publication Number:
  US 20090001980A1
• Time in Patent Office: 1,033 Days
• Field of Search: 324/207.21, 324/249, 324/252, 360313-316, 360324-327
• US Class Current: 324/252
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/091 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00

Abstract

An embodiment includes a radio frequency (RF) sensor system having a plurality of magnetoresistive (MR) sensors, where each MR sensor includes a configuration of MR elements and is adapted to produce a time-varying output voltage in response to a time-varying, external magnetic field. The RF sensor system also includes combiner circuitry, electrically coupled to the plurality of MR sensors, and adapted to receive and combine a plurality of time-varying output voltages from the plurality of MR sensors to generate a sensor output voltage. Another embodiment includes an electromagnetic sensor array having a plurality of MR sensors arranged in an array configuration, where each MR sensor includes a plurality of MR elements forming a Wheatstone bridge circuit, and where each MR sensor is adapted to produce a time-varying output voltage in response to a time-varying, external magnetic field. Still another embodiment includes a method for manufacturing an electromagnetic sensor array.

Claims

1. A radio frequency (RF) sensor system comprising:

a plurality of magnetoresistive sensors, wherein each magnetoresistive sensor includes a configuration of magnetoresistive elements and is adapted to produce a time-varying output voltage in response to a time-varying, external magnetic field;

combiner circuitry, electrically coupled to the plurality of magnetoresistive sensors, and adapted to receive and combine a plurality of time-varying output voltages from the plurality of magnetoresistive sensors to generate a sensor output voltage; and

a structure, magnetically coupled to the plurality of magnetoresistive sensors, and adapted to carry the time-varying, external magnetic field in response to an RF signal incident upon the structure.

2. The RF sensor system of claim 1, wherein the configuration of magnetoresistive elements includes a configuration of giant magnetoresistive elements.

3. The RF sensor system of claim 1, wherein the configuration of magnetoresistive elements includes a Wheatstone bridge circuit that includes at least four magnetoresistive elements forming resistive elements of the Wheatstone bridge circuit.

4. The RF sensor system of claim 3, wherein the at least four magnetoresistive elements include at least one shielded magnetoresistive element.

5. The RF sensor system of claim 1, wherein the plurality of magnetoresistive sensors includes an array of magnetoresistive sensors.

6. The RF sensor system of claim 1, wherein the combiner circuitry is configured to combine at least some of the plurality of time-varying output voltages in series to produce the sensor output voltage.

7. The RF sensor system of claim 6, further comprising:

an amplifier, electrically coupled to the combiner circuitry, and adapted to amplify the sensor output voltage.

8. The RF sensor system of claim 1, wherein the plurality of magnetoresistive sensors are formed on a semiconductor substrate.

9. The RF sensor system of claim 1, wherein the structure comprises a conductive mesh structure.

10. The RF sensor system of claim 1, wherein the structure comprises a conductive ground plane, magnetically coupled to the plurality of magnetoresistive sensors, and adapted to carry the time-varying, external magnetic field in response to an RF signal incident upon the conductive ground plane.

11. The RF sensor system of claim 10, wherein the conductive ground plane forms a portion of an outer covering of an aircraft.

12. The RF sensor system of claim 1, wherein the plurality of magnetoresistive sensors and the combiner circuitry form a portion of a magnetoresistive sensor array level, and wherein the RF sensor system further comprises:

an exterior layer, coupled to a first side of the magnetoresistive sensor array layer, wherein the exterior layer is adapted to protect the magnetoresistive sensor array layer;

a contact layer, coupled to a second side of the magnetoresistive sensor array layer, wherein the contact layer is adapted to electrically insulate the magnetoresistive sensor array layer; and

an adhesive layer, coupled to the contact layer, wherein the adhesive layer is adapted to enable the RF sensor system to be adhered to a structure.

13. An electromagnetic sensor array comprising:

a plurality of magnetoresistive sensors arranged in an array configuration, wherein each magnetoresistive sensor includes a plurality of magnetoresistive elements forming a Wheatstone bridge circuit, and wherein each magnetoresistive sensor is adapted to produce a time-varying output voltage in response to a time-varying, external magnetic field and

a structure, magnetically coupled to the plurality of magnetoresistive sensors, and adapted to carry the time-varying, external magnetic field in response to an RF signal incident upon the structure.

14. The electromagnetic sensor array of claim 13, wherein the Wheatstone bridge circuit comprises:

a first resistance leg comprising a first unshielded magnetoresistive element and a first shielded magnetoresistive element electrically coupled in series; and

a second resistance leg, electrically coupled in parallel to the first resistance leg, and comprising a second unshielded magnetoresistive element and a second shielded magnetoresistive element electrically coupled in series.

15. The electromagnetic sensor array of claim 13, further comprising:

routing circuitry, electrically coupled to output terminals of the plurality of magnetoresistive sensors, and adapted to enable a plurality of time-varying output voltages generated by the plurality of magnetoresistive sensors to be combined.

16. The electromagnetic sensor array of claim 13, further comprising:

combiner circuitry, electrically coupled to the plurality of magnetoresistive sensors, and adapted to receive and combine a plurality of time-varying output voltages from the plurality of magnetoresistive sensors to generate a sensor output voltage.

17. The electromagnetic sensor array of claim 16, further comprising:

an amplifier, electrically coupled to the combiner circuitry, and adapted to amplify the sensor output voltage.

18. A method for manufacturing an electromagnetic sensor array comprising the steps of:

forming, on a semiconductor substrate, a plurality of magnetoresistive sensors, wherein each magnetoresistive sensor includes a configuration of magnetoresistive elements and is adapted to produce a time-varying output voltage in response to a time-varying, external magnetic field;

forming routing circuitry, over the plurality of magnetoresistive sensors, wherein the routing circuitry is electrically coupled to output terminals of the plurality of magnetoresistive sensors, and enables a plurality of time-varying output voltages generated by the plurality of magnetoresistive sensors to be combine; and

physically coupling the electromagnetic sensor array to a structure adapted to carry the time-varying, external magnetic field in response to an RF signal incident upon the structure.

19. The method of claim 18, wherein forming the plurality of magnetoresistive sensors comprises:

forming each of the plurality of magnetoresistive sensors as a Wheatstone bridge circuit that includes

a first resistance leg comprising a first unshielded magnetoresistive element and a first shielded magnetoresistive element electrically coupled in series, and

a second resistance leg, electrically coupled in parallel to the first resistance leg, and comprising a second unshielded magnetoresistive element and a second shielded magnetoresistive element electrically coupled in series.

20. The method of claim 18, further comprising:

packaging the electromagnetic sensor array as a large scale integrated circuit.