# US 2019/0171922 A1 · Rfid tag > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0171922 A1 - Document ID: US20190171922A1 - Status: Published application - Kind: A1 - Application number: 16/200,719 - Filed: 2018-11-27 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Toshiba Tec Kabushiki Kaisha - Applicants: Toshiba Tec Kabushiki Kaisha - Inventors: Naohiro Matsushita - Web page: https://patentgrep.com/patent/US20190171922A1 ## CPC - G06K 19/07773: {Antenna details (antennas for wireless devices, e.g. RFID tags, in general H01Q1/22)} - G06K 7/10059: {transponder driven} - G06K 19/07345: {by activating or deactivating at least a part of the circuit on the record carrier, e.g. ON/OFF switches} - G06K 19/07771: {the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object} - 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} - H01Q 9/065: {Microstrip dipole antennas (patch antenna H01Q9/0407)} - H01Q 9/145: {by varying the electrical length} - H01Q 1/248: {provided with an AC/DC converting device, e.g. rectennas} - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract According to one embodiment, an RFID tag includes a plurality of antenna elements, a switch, and a control circuit. The switch is inserted between the plurality of antenna elements. The control circuit turns off the switch until a specified time elapsed after responding to radio waves from a reader device. ## Claims ### Claim 1 An RFID tag comprising: a plurality of antenna elements; a switch positioned between the plurality of antenna elements; and a control circuit configured to turn off the switch until a specified time elapses after responding to radio waves from a reader device. ### Claim 2 (depends on 1) The tag according to claim 1, further comprising: a register configured to store flag information being in an ON state when responding to the radio waves from the reader device and being in an OFF state when the specified time elapses after the responding, wherein the control circuit controls the switch in conjunction with the flag information. ### Claim 3 (depends on 1) The tag according to claim 1, further comprising: a passive-type IC chip connecting one end of each of the plurality of antenna elements linked through the switch, wherein the IC chip includes the control circuit. ### Claim 4 (depends on 1) The tag according to claim 1, wherein a total length when the plurality of antenna elements are connected through a plurality of switches is included in a wavelength of a frequency band for communication with the reader device, and a resonant frequency with a length of each antenna element when the plurality of antenna elements are electrically disconnected by the switches becomes a higher frequency band compared to a frequency band for communication. ### Claim 5 (depends on 1) The tag according to claim 1, wherein a plurality of switches are provided, and a total length when three or more antenna elements are linked through the plurality of switches is included in a wavelength of a frequency band for communication with the reader device. ### Claim 6 (depends on 1) The tag according to claim 1, wherein the switch is a high frequency switch. ### Claim 7 (depends on 1) The tag according to claim 1, wherein the switch comprises a gallium arsenide FET. ### Claim 8 (depends on 1) The tag according to claim 1, wherein the switch is configured to electrically connect the plurality of antenna elements in an ON state and electrically disconnect the plurality of antenna elements in an OFF state. ### Claim 9 (depends on 1) The tag according to claim 1, wherein the RFID tag is a passive type RFID tag. ### Claim 10 An RFID tag comprising: a plurality of at least three antenna elements; a plurality of at least two switches each positioned between a different set of two antenna elements; and a control circuit configured to turn off the plurality of switches until a specified time elapses after responding to radio waves from a reader device. ### Claim 11 (depends on 10) The tag according to claim 10, further comprising: a register configured to store flag information being in an ON state when responding to the radio waves from the reader device and being in an OFF state when the specified time elapses after the responding, wherein the control circuit controls the plurality of switches in conjunction with the flag information. ### Claim 12 (depends on 10) The tag according to claim 10, further comprising: a passive-type IC chip connecting one end of each of the plurality of antenna elements linked through the plurality of switches, wherein the IC chip includes the control circuit. ### Claim 13 (depends on 10) The tag according to claim 10, wherein a total length when the plurality of antenna elements are connected through a plurality of switches is included in a wavelength of a frequency band for communication with the reader device, and a resonant frequency with a length of each antenna element when the plurality of antenna elements are electrically disconnected by the plurality of switches becomes a higher frequency band compared to a frequency band for communication. ### Claim 14 (depends on 10) The tag according to claim 10, wherein the plurality of switch are configured to electrically connect the plurality of antenna elements in an ON state and electrically disconnect the plurality of antenna elements in an OFF state. ### Claim 15 (depends on 10) The tag according to claim 10, wherein the RFID tag is a passive type RFID tag. ### Claim 16 A method of mitigating interference when reading an RFID tag from a group of RFID tags densely arranged, comprising: turning off a switch positioned between a plurality of antenna elements until a specified time elapses after responding to radio waves from a reader device. ### Claim 17 (depends on 16) The method according to claim 16, further comprising: storing flag information being in an ON state when responding to the radio waves from the reader device and being in an OFF state when the specified time elapses after the responding, wherein turning off the switch is performed in conjunction with the flag information. ### Claim 18 (depends on 16) The method according to claim 16, wherein a total length when the plurality of antenna elements are connected through a plurality of switches is included in a wavelength of a frequency band for communication with the reader device, and a resonant frequency with a length of each antenna element when the plurality of antenna elements are electrically disconnected by the switches becomes a higher frequency band compared to a frequency band for communication. ### Claim 19 (depends on 16) The method according to claim 16, wherein turning off the switch comprises turning off a plurality of switches, and a total length when three or more antenna elements are linked through the plurality of switches is included in a wavelength of a frequency band for communication with the reader device. ### Claim 20 (depends on 16) The method according to claim 16, further comprising: at least one of electrically connecting the plurality of antenna elements in an ON state and electrically disconnecting the plurality of antenna elements in an OFF state.