System for isolating radio propagation zones

• US 7,369,049 B1
• Filed: 11/09/2007
• Issued: 05/06/2008
• Est. Priority Date: 11/09/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Duri, Sastry S., Moskowitz, Paul A., De Gennaro, Steven V.
• Primary Examiner(s): Bugg; George
• Assistant Examiner(s): Walk; Samuel J
• Application Number:
  US11/937,958
• Time in Patent Office: 179 Days
• Field of Search: 340/10.1, 340/572.1, 700/214, 700/215, 700/217, 343/838, 343/841
• US Class Current: 340/572.1
• 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: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A radio frequency identification (RFID) system including a transponder, an antenna, and a reader, the antenna coupled to the reader, the antenna and the reader for transmitting a radio signal to the transponder and for receiving a response radio signal from the transponder, the response radio signal including data from the transponder, the system further including: a curtain that limits propagation of the radio signal; wherein the curtain includes a plurality of flexible strips transparent to visible light, the long edge of each of the strips is oriented in substantially the vertical direction, more than one strip overlaps a portion of the width of an adjacent strip along the length of the adjacent strip, and the length of each of the strips is substantially greater than the width of each of the strips.

Claims

1. A radio frequency identification (RFID) system comprising a transponder, an antenna, and a reader, the antenna coupled to the reader, the antenna and the reader for transmitting a radio signal to the transponder and for receiving a response radio signal from the transponder, the response radio signal comprising data from the transponder, the system further comprising:

a curtain that limits propagation of the radio signal;

wherein the curtain comprises a plurality of flexible strips transparent to visible light, the long edge of each of the strips is oriented in substantially the vertical direction, more than one strip overlaps a portion of the width of an adjacent strip along the length of the adjacent strip, and the length of each of the strips is substantially greater than the width of each of the strips.

2. The system as in claim 1, wherein the curtain is associated with a portal through which a person, a vehicle, and an object can pass, the portal separating a first region containing the RFID system from a second region containing at least one of another transponder and another antenna.

3. The system as in claim 1, wherein more than one strip overlaps the adjacent strip by about fifty percent of the width of the adjacent strip.

4. The system as in claim 1, wherein the strips absorb the radio signal.

5. The system as in claim 4, wherein the strips comprise ferrite particles.