Apparatus for measuring read range between RFID tag and reader

• US 7,161,357 B2
• Filed: 12/07/2005
• Issued: 01/09/2007
• Est. Priority Date: 05/17/2005
• Status: Expired due to Fees

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Pyo, Cheol Sig, Kim, Nae Soo, Chae, Jong Suk, Lee, Jong Moon
• Primary Examiner(s): Nguyen; Vincent Q.
• Application Number:
  US11/296,056
• Publication Number:
  US 20060261821A1
• Time in Patent Office: 398 Days
• Field of Search: 324/627
• US Class Current: 324/600
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
• CPC Class Codes: G01R 29/0821 rooms and test sites therefor, e.g. anechoic chambers, open field sites or TEM cells for testing antennas G01R29/105
• CPC Class Codes: G01R 29/0871 Complete apparatus or systems; circuits, e.g. receivers or amplifiers G01R29/0878, G01R29/0892 take precedence; dosimeters, warning devices G01R29/0857
• CPC Class Codes: G01R 31/2822 of microwave or radiofrequency circuits of attenuation, gain, e.g. using network analyzers G01R27/28

Abstract

Provided is an apparatus for measuring a read range between a tag and a reader, which includes an electromagnetic anechoic chamber formed by connecting at least one unit cell in a row, the unit cell having an electromagnetic wave absorbent provided on an inner wall of each unit cell, an electromagnetic generation portion located at the unit cell at an end of the electromagnetic anechoic chamber and transmitting an electromagnetic wave through an antenna, and an electromagnetic measurement portion which measures a field strength of the electromagnetic wave transmitted from the electromagnetic generation portion using an electric field probe moving in the electromagnetic anechoic chamber.

Claims

1. An apparatus for measuring a read range between a tag and a reader, the apparatus comprising:

an electromagnetic anechoic chamber comprising;

two end unit cells, each end unit cell having an inner wall with an opening;

wherein an electromagnetic wave absorbent is provided on the inner wall, and

wherein the opening of each end cell is capable of being joined to an opening of the other end unit cell;

an electromagnetic generation portion located at one end unit cell of the electromagnetic anechoic chamber and transmitting an electromagnetic wave through an antenna; and

an electromagnetic measurement portion which measures a field strength of the electromagnetic wave transmitted from the electromagnetic generation portion using an electric field probe moving in the electromagnetic anechoic chamber.

2. The apparatus as claimed in claim 1, wherein the end unit cells are joined at their openings to form the electromagnetic anechoic chamber.

3. The apparatus as claimed in claim 2, wherein the end unit cell has a carbon-based electromagnetic wave absorbent which is provided on the inner wall.

4. The apparatus as claimed in claim 2, wherein the electromagnetic generation portion moves the antenna up and down and rotate the antenna at a predetermined angle.

5. The apparatus as claimed in claim 2, wherein the electromagnetic generation portion comprises:

the antenna emitting an electromagnetic wave;

an external connector connecting the antenna and an external RFID reader; and

an antenna support portion having an arm located at a rod having a predetermined length, fixing the antenna at an end of the arm, and performing an up/down motion of the rod and a rotational motion of the arm.

6. The apparatus as claimed in claim 2 wherein the electromagnetic measurement portion allows the electric field probe to linearly move along the end unit cells, move up/down, and rotate at a predetermined angle in the electromagnetic anechoic chamber.

7. The apparatus as claimed in claim 2, wherein the electromagnetic measurement portion comprises:

an electric field probe measuring a field strength of an electromagnetic wave transmitted from the electromagnetic generation portion;

a tag support portion having a rod having a predetermined length and arm located at an end of the rod, the electric field probe being fixed to an end of the arm, and performing an up/down motion of the rod and a rotational motion of the arm; and

a stepping motor moving the tag support portion between the unit cells at both ends of the electromagnetic anechoic chamber.

8. The apparatus as claimed in claim 2, further comprising a positional control portion controlling up/down and rotational motions of the antenna of the electromagnetic generation portion and a movement of the electric field probe of the electromagnetic measurement portion.

9. The apparatus as claimed in claim 2, further comprising a central control portion checking a field strength according to a relative position between the antenna and the electric field probe.

10. The apparatus as claimed in claim 2, further comprising a pattern analysis portion measuring a transmission pattern of the tag and the reader in a near field antenna measurement method when the tag and the reader are located at the electromagnetic measurement portion and a standard antenna suitable for the tag and the reader is located at the electromagnetic generation portion.

11. The apparatus as claimed in claim 1 further comprising;

one or more mid unit cells, each having two openings, wherein each opening of the mid unit cell is capable of being joined to the opening of the end unit cell or the opening of another mid unit cell.

12. The apparatus as claimed in claim 11, wherein the electromagnetic anechoic chamber is formed by joining the openings of the two end unit cells and one or more mid unit cells therebetween the two end unit cells.

13. The apparatus as claimed in claim 12, wherein each of the end unit cells and the mid unit cells has a carbon-based electromagnetic wave absorbent which is provided on the inner wall.

14. The apparatus as claimed in claim 12, wherein the electromagnetic generation portion moves the antenna up and down and rotate the antenna at a predetermined angle.

15. The apparatus as claimed in claim 12, wherein the electromagnetic generation portion comprises:

the antenna emitting an electromagnetic wave;

an external connector connecting the antenna and an external RFID reader; and

an antenna support portion having an arm located at a rod having a predetermined length, fixing the antenna at an end of the arm, and performing an up/down motion of the rod and a rotational motion of the arm.

16. The apparatus as claimed in claim 12 wherein the electromagnetic measurement portion allows the electric field probe to linearly move along the end unit cells and the mid units cells joined to each other, move up/down, and rotate at a predetermined angle in the electromagnetic anechoic chamber.

17. The apparatus as claimed in claim 12, wherein the electromagnetic measurement portion comprises:

an electric field probe measuring a field strength of an electromagnetic wave transmitted from the electromagnetic generation portion;

a tag support portion having a rod having a predetermined length and arm located at an end of the rod, the electric field probe being fixed to an end of the arm, and performing an up/down motion of the rod and a rotational motion of the arm; and

a stepping motor moving the tag support portion between the unit cells at both ends of the electromagnetic anechoic chamber.

18. The apparatus as claimed in claim 12, further comprising a positional control portion controlling up/down and rotational motions of the antenna of the electromagnetic generation portion and a movement of the electric field probe of the electromagnetic measurement portion.

19. The apparatus as claimed in claim 12, further comprising a central control portion checking a field strength according to a relative position between the antenna and the electric field probe.

20. The apparatus as claimed in claim 12, further comprising a pattern analysis portion measuring a transmission pattern of the tag and the reader in a near field antenna measurement method when the tag and the reader are located at the electromagnetic measurement portion and a standard antenna suitable for the tag and the reader is located at the electromagnetic generation portion.