Patch antenna for RFID tag

• US 7,605,706 B2
• Filed: 05/13/2005
• Issued: 10/20/2009
• Est. Priority Date: 05/13/2005
• Status: Expired due to Fees

• Current Assignee: Kennedy Group (Ivan Bloom & Associates)
• Original Assignee: The Kennedy Group, Incorporated
• Inventors: Khatri, Mohamed Fayaz
• Primary Examiner(s): Lee; Benjamin C
• Assistant Examiner(s): Previl; Daniel
• Application Number:
  US11/129,094
• Publication Number:
  US 20060255946A1
• Time in Patent Office: 1,621 Days
• Field of Search: 340/568.1, 340/572.1, 340/572.7, 340/572.8, 340/572.4, 340/531, 340/539.1, 340/539.11, 340/539.13, 343/872, 343/873, 343/846, 343/700.R
• US Class Current: 340/572.7
• CPC Class Codes: G06K 19/077 Constructional details, e.g. mounting of circuits in the carrier
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

An antenna for use with a Radio Frequency Identification, RFID, tag. A well-known, simple “patch antenna” is formed by two metallic plates, one larger than the other, between which is sandwiched a dielectric sheet. Under the invention, the larger metallic plate is provided by the wall of a metallic shipping container. Thus, one form of the invention includes (1) the smaller metallic sheet, (2) the dielectric sheet, and (3) an RFID circuit. When the dielectric sheet is attached to the wall of the shipping container, a patch antenna is generated which the RFID circuit can use.

Claims

1. An apparatus comprising:

a) a dielectric sheet having a top surface and a bottom surface;

b) a conductive sheet adjacent to the top surface;

c) a conductive pad adjacent to the bottom surface;

d) a passive RFID circuit comprising;

i) a signal lead connected to the conductive sheet; and

ii) a ground lead connected to the conductive pad;

wherein the conductive pad by itself is not effective to act as a ground plane in a patch antenna connected with the passive RFID circuit, although the conductive pad is configured for selective placement adjacent to a metallic surface of a shipping container that is effective to act as a ground plane in a patch antenna connected with the passive RFID circuit.

2. The apparatus according to claim 1, wherein the ground lead and the conductive pad facilitate connection of the passive RFID circuit to a metallic surface of a shipping container.

3. The apparatus according to claim 1, further comprising an adhesive sheet adjacent to the bottom surface of the dielectric sheet and configured to facilitate selective securement of the dielectric sheet to a metallic surface of a shipping container.

4. The apparatus according to claim 1, wherein the passive RFID circuit is embedded within the dielectric sheet.

5. The apparatus according to claim 1, further comprising a label positioned to be visible when the dielectric sheet is secured to a metallic surface of a shipping container.

6. The apparatus according to claim 1, wherein the ground lead extends through the dielectric sheet in connecting the passive RFID circuit and the conductive pad.