READER APPARATUS

• US 20090309737A1
• Filed: 08/21/2007
• Published: 12/17/2009
• Est. Priority Date: 08/26/2006
• Status: Abandoned Application

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Jarman, Timothy Rupert Charles, Hopkins, Michael William, Bowles, Adrian Robert
• Application Number:
  US12/375,808
• Publication Number:
  US 20090309737A1
• Time in Patent Office: Days
• US Class Current: 340/573.100
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil

Abstract

Reader apparatus for receiving data from a transponder in the body of a patient, for example a femoral nail. The apparatus includes an antenna which can be varied in size and shape to fit patients, the size and shape of whose bodies vary significantly. A variable impedance unit is included to maximise power matching between the antenna and a reader unit for a given antenna configuration.

Claims

1. Reader apparatus for receiving data from a transponder in the body of a patient, the apparatus comprising:

an extendible antenna and

a reader unit including a variable impedance unit

wherein the variable impedance unit is adjusted to maximise power matching between the antenna and the reader unit for a given antenna extension.

2. Apparatus according to claim 1, wherein the variable impedance unit is coupled to the antenna such that adjustment of the antenna to a selected extension automatically adjusts the variable impedance unit to a corresponding impedance value.

3. Apparatus according to claim 2, wherein said impedance unit is adjusted in dependence upon the antenna extension.

4. Apparatus according to any preceding claim 1, wherein the antenna is extendible in discrete increments.

5. Apparatus according to claim 1, wherein the variable impedance unit is adjustable in discrete increments.

6. Apparatus according to claim 1, adapted to determine a measure of power matching, and whereby the variable impedance unit is automatically adjusted in dependence upon said measure.

7. Apparatus according to claim 1, adapted to determine a measure of quality of the received signal, and whereby the variable impedance unit is automatically adjusted in dependence upon said measure.

8. Apparatus according to claim 6, wherein the Standing Wave Ratio (SWR) is monitored at the reader.

9. Apparatus according to claim 6, wherein the received signal amplitude is monitored at the reader.

10. Apparatus according to claim 6, wherein said measure is determined periodically.

11. Apparatus according to claim 6, wherein said measure is determined after each adjustment in length of the antenna.

12. Apparatus according to claim 1, wherein the antenna is adapted to be worn about the body.