Antenna

• US 7,154,449 B2
• Filed: 04/25/2002
• Issued: 12/26/2006
• Est. Priority Date: 04/25/2002
• Status: Expired due to Fees

• Current Assignee: Cet Technoloiges Pte., Ltd. (Singapore Technologies Engineering Limited)
• Original Assignee: Cet Technoloiges Pte., Ltd. (Singapore Technologies Engineering Limited)
• Inventors: Zhuang, Zhiming, Chung, Say Kin, Seah, Alice Lee Eng, Liu, Jay Zheyi
• Primary Examiner(s): Ho, Tan
• Application Number:
  US10/512,428
• Publication Number:
  US 20050179604A1
• Time in Patent Office: 1,706 Days
• Field of Search: 343/741, 343/742, 343/867, 343/895, 340/10.2, 340/572.5, 340/570, 340/572.1
• US Class Current: 343/867
• 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 19/07779 the inductive antenna being a coil
• CPC Class Codes: G06K 19/07783 the coil being planar
• CPC Class Codes: G06K 19/07784 the inductive antenna consisting of a plurality of coils stacked on top of one another
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 5/385 Two or more parasitic elements
• CPC Class Codes: H01Q 5/49 with parasitic elements used for purposes other than for dual-band or multi-band, e.g. imbricated Yagi antennas
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

An antenna suitable for use in a Radio Frequency Identification (RFID) tag is disclosed. The antenna includes a plurality of discrete loop antennas (130, 140, 150) disposed concentrically on a substrate. Each one of said plurality of loop antennas is electrically isolated from each other one of said plurality of loop antennas.

Claims

1. An antenna for use in a Radio Frequency Identification (RFID) tag, including a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas.

2. An antenna as claimed in claim 1 wherein the loop antennas are generally rectangular in shape.

3. An antenna as claimed in claim 1 wherein the loop antennas are meander loop antennas.

4. An antenna as claimed in claim 1 wherein the substrate is a printed circuit board (PCB).

5. An antenna as claimed in claim 1 further including electronic circuity disposed on the substrate within an area defined by the antenna.

6. An antenna for use in a Radio Frequency Identification (RFID) tag, including a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein ones of the plurality of loop antennas are disposed on different layers of the substrate.

7. An antenna for use in a Radio Frequency Identification (RFID) tag, including a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein the antenna includes:

a closed outer loop antenna

a closed inner loop antenna; and

an open feed loop antenna extending between a pair of feed terminals, said feed loop antenna being disposed between said outer and inner loop antennas.

8. A Radio Frequency Identification (RFID) tag comprising

an antenna having a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas.

9. A Radio Frequency Identification (RFID) tag comprising an antenna having a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein the tag is an active tag, and further includes a battery.

10. A Radio Frequency Identification (RFID) tag comprising an antenna having a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein the antenna includes:

a closed outer loop antenna

a closed inner loop antenna; and

an open feed loop antenna extending between a pair of feed terminals, said feed loop antenna being disposed between said outer and inner loop antennas.

11. An antenna for use in a Radio Frequency Identification (RFID) tag, including a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein the widths of the traces defining at least two loops are different from each other.

12. A Radio Frequency Identification (RFID) tag comprising an antenna having a plurality of discrete loop antennas disposed concentrically on a substrate, each one of said plurality of loop antennas being electrically isolated from each other one of said plurality of loop antennas,

wherein the widths of the traces defining at least two loops are different from each other.