# US 2025/0094744 A1 · Rfid antenna, rfid tag and rfid system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0094744 A1 - Document ID: US20250094744A1 - Status: Published application - Kind: A1 - Application number: 18/899,087 - Filed: 2024-09-27 - Published: 2025-03-20 - Earliest claimed: 2023-03-31 - Assignees: Logistics and Supply Chain MultiTech R&D Centre Limited - Applicants: Logistics and Supply Chain MultiTech R&D Centre Limited - Inventors: Jing Jung Tang; Leung Chiu; Xiao Sheng Chen - Web page: https://patentgrep.com/patent/US20250094744A1 ## CPC - G06K 7/10356: {using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas} - G06K 7/10346: {the antenna being of the far field type, e.g. HF types or dipoles} - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract There is provided an antenna for a radio frequency identification (RFID) tag, which includes a loop antenna, an amplifying antenna, an additional antenna structure to modify impedance of the entire antenna. The additional antenna structure has a first electromagnetic coupling with the amplifying antenna and a second electromagnetic coupling with the loop antenna. ## Claims ### Claim 1 An antenna for a radio frequency identification (RFID) tag, comprising: a loop antenna; an amplifying antenna; and an additional antenna structure to modify impedance of the entire antenna, wherein the additional antenna structure has a first electromagnetic coupling with the amplifying antenna and a second electromagnetic coupling with the loop antenna. ### Claim 2 (depends on 1) The antenna of claim 1, wherein the loop antenna is arranged on a first layer structure and the amplifying antenna is arranged on a second layer structure, wherein the first layer structure and the second layer structure are detachably combined. ### Claim 3 (depends on 1) The antenna of claim 1, wherein the loop antenna and the amplifying antenna are optimized for impedance matching to provide an increased readable range in a forward link. ### Claim 4 (depends on 1) The antenna of claim 1, wherein the first layer structure and the second layer structure comprise a dielectric material. ### Claim 5 (depends on 1) The antenna of claim 1, wherein the loop antenna, the amplifying antenna and the additional antenna structure comprise a metallic material. ### Claim 6 (depends on 1) The antenna of claim 1, wherein the first layer structure is a form of a rectangular card and the second layer structure is a form of a card holder which is configured to hold the card-shaped first layer structure. ### Claim 7 (depends on 1) The antenna of claim 1, wherein the amplifying antenna is geometrically shaped. ### Claim 8 (depends on 7) The antenna of claim 7, wherein the amplifying antenna is H-shaped. ### Claim 9 (depends on 1) The antenna of claim 1, wherein a geometry of the additional antenna structure is optimized to enhance a reverse link. ### Claim 10 (depends on 1) The antenna of claim 1, wherein the additional antenna structure comprises a metallic strip. ### Claim 11 (depends on 1) The antenna of claim 1, wherein the amplifying antenna is H-shaped and the additional antenna structure extends in a horizontal direction and is arranged between vertical elements of the H-shaped amplifying antenna. ### Claim 12 (depends on 11) The antenna of claim 11, wherein the additional antenna structure is arranged between the vertical elements of the H-shaped amplifying antenna, with a gap between respective ends of the additional antenna structure and respective vertical elements of the amplifying antenna. ### Claim 13 (depends on 12) The antenna of claim 12, wherein a width of the gap and a width of the additional antenna structure are optimized to enhance a reverse link. ### Claim 14 (depends on 1) The antenna of claim 1, wherein at least a part of the additional antenna structure is overlapped with a part of the loop antenna. ### Claim 15 (depends on 1) The antenna of claim 1, wherein the first electromagnetic coupling and the second electromagnetic coupling comprise capacitive coupling. ### Claim 16 A method for improving a reverse link in a radio frequency identification (RFID) system including a RFID reader and a RFID tag, comprising: providing an antenna of the RFID tag, the antenna including a loop antenna and an amplifying antenna which are detachably combined; providing an additional antenna structure to the amplifying antenna to modify impedance of the entire antenna of the RFID tag; and optimizing a geometry of the additional antenna structure to obtain a desired impedance of the entire antenna. ### Claim 17 (depends on 16) The method of claim 16, wherein providing the antenna of the RFID tag comprises: providing the loop antenna on a first layer structure; and providing the amplifying antenna on a second layer structure. ### Claim 18 (depends on 17) The method of claim 17, wherein providing the additional antenna structure comprises providing a metallic strip to the amplifying antenna on the second layer structure. ### Claim 19 (depends on 18) The method of claim 18, wherein providing the amplifying antenna comprises providing an H-shaped amplifying antenna, and providing the metallic strip comprises providing the metallic strip to extend in a horizontal direction and to be arranged between vertical elements of the H-shaped amplifying antenna. ### Claim 20 (depends on 19) The method of claim 19, wherein providing the metallic strip comprises providing the metallic strip between vertical elements of the H-shaped amplifying antenna, leaving a gap between respective ends of the metallic strip and respective vertical elements of the amplifying antenna. ### Claim 21 (depends on 20) The method of claim 20, wherein optimizing the geometry of the additional antenna structure comprises optimizing a width of the gap and a width of the metallic strip.