System and method for measuring RFID signal strength within shielded locations

• US 7,825,771 B2
• Filed: 07/14/2008
• Issued: 11/02/2010
• Est. Priority Date: 06/28/2006
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Boss, Gregory J., Polozoff, Alexandre, Waters, Timothy M., Hamilton, Rick A. II, Bhogal, Kulvir S.
• Primary Examiner(s): Lu; Shirley
• Application Number:
  US12/172,552
• Publication Number:
  US 20090009333A1
• Time in Patent Office: 841 Days
• Field of Search: 340/572.1, 340/552, 340/10.1, 235/385, 324/600, 455/69.11, 455/67, 455/67.7, 455/67.12, 455/67.14
• US Class Current: 340/10.1
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 17/318 Received signal strength

Abstract

An RFID Probe comprises a pole with a plurality of sensors that indicate RF signal strength attached at regular intervals and marked to indicate distance from an end of the pole. A user employs the RFID Probe by placing the probe between densely packed materials, such as cases on a pallet, and exposing the RFID Probe and packaging to a signal from a RIFD transceiver. After exposing the RFID Probe to the RFID transceiver signal, the user removes the RFID Probe from the packed materials and observes the sensors on the probe. By noting the location on the probe of the sensors indicating low or no RF signal, the user can identify locations where RF signal strength is insufficient to activate an RFID tag.

Claims

1. A process for systematically identifying a dead spot for an RF signal in a package stack, the process comprising:

inserting a probe into the package stack, the probe having a plurality of attached RF sensors adapted to provide an indication of an intensity of exposure to the RF signal;

transmitting the RF signal from a RFID transceiver;

responsive to transmitting the RF signal, reading the plurality of attached RF sensors to identify a location of the dead spot of the RF signal in the package stack; and

calculating the location of the dead spot by one of measuring the distance from an end of the probe to a sensor of the plurality of attached RF sensors that indicates an intensity of exposure to the RF signal and measuring a distance between a first indicating sensor and a second indicating sensor, wherein the first indicating sensor and the second indicating sensor are sensors of the plurality of attached RF sensors that indicate an intensity of exposure to the RF signal.

2. The process of claim 1 further comprising the step of:

placing an RF repeater to retransmit the RF signal to the dead spots.

3. The process of claim 1 wherein a plurality of passive RFID tags are affixed within the package stack.

4. The process of claim 3 further comprising the step of:

repositioning a passive RFID tag located in a dead spot within the package stack to an area of the package stack where the passive RFID tag can receive the RF signal.

5. An apparatus comprising:

a pole having a plurality of sensors spaced at regular intervals along the pole, the pole adapted for insertion into a package stack, wherein the sensors provide an indication of an intensity of exposure to an RF signal inside the package stack and to calculate the location of a dead spot by one of measuring the distance from an end of the probe to a sensor of the plurality of attached RF sensors that indicates an intensity of exposure to the RF signal and measuring a distance between a first indicating sensor and a second indicating sensor, wherein the first indicating sensor and the second indicating sensor are sensors of the plurality of attached RF sensors that indicate an intensity of exposure to the RF signal.

6. The apparatus of claim 5 wherein each of the plurality of sensors comprise an electronic display.

7. The apparatus of claim 6 wherein the electronic display further comprises a RFID receiver coupled to a LED.

8. The apparatus of claim 5 wherein each of the plurality of sensors comprises a RF sensitive LCD.

9. The apparatus of claim 5 wherein each of the plurality of sensors comprises a carbon coated acrylonitrile butadiene styrene plastic.

10. A system comprising:

a pole having a plurality of sensors spaced at regular intervals along the pole, the pole adapted for insertion into a package stack, wherein the sensors provide an indication of an intensity of exposure to an RF signal inside the package stack and wherein each of the sensors comprise a RFID receiver coupled to a LED and to calculate the location of a dead spot by one of measuring the distance from an end of the probe to a sensor of the plurality of attached RF sensors that indicates an intensity of exposure to the RF signal and measuring a distance between a first indicating sensor and a second indicating sensor, wherein the first indicating sensor and the second indicating sensor are sensors of the plurality of attached RF sensors that indicate an intensity of exposure to the RF signal.