# US 11,121,742 B2 · Self-detaching anti-theft device with a multi-purpose transceiver for energy harvesting and communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,742 B2 - Document ID: US11121742B2 - Status: Granted - Kind: B2 - Application number: 16/784,659 - Filed: 2020-02-07 - Published: 2021-03-25 - Granted: 2021-09-14 - Earliest claimed: 2019-09-19 - Assignees: Sensormatic Electronics Corporation - Applicants: Sensormatic Electronics, LLC - Inventors: Adam S. Bergman; Ronald B. Easter; Mohammad Mohiuddin - Web page: https://patentgrep.com/patent/US11121742B2 ## CPC - G08B 13/2414: {using inductive tags} - H04B 5/48: Transceivers - G06K 19/0723: {the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs} - G08B 13/2431: {Tag circuit details} - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS - H04B: TRANSMISSION - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract Systems and methods for operating a security tag. The methods comprise: performing communication operations by the security tag at a communications frequency; using a receive circuit of the security tag to harvest energy emitted from a transmit circuit of an external device at an energy harvesting frequency. The communications frequency is out of band of the energy harvesting frequency. ## Claims ### Claim 1 A method for operating a security tag, comprising: performing communication operations by the security tag at a communications frequency; using a receive circuit of the security tag to harvest energy emitted from a transmit circuit of an external device at an energy harvesting frequency; and wherein: the communications frequency is out of band of the energy harvesting frequency, and the transmit circuit comprises a capacitor, an inductor connected to a first terminal of the capacitor; and a voltage source coupled a second terminal of the capacitor and tuned to a frequency of the capacitor and inductor. ### Claim 2 (depends on 1) The method according to claim 1, wherein the energy harvesting frequency is higher or lower than the communications frequency. ### Claim 3 (depends on 1) The method according to claim 1, wherein the energy is harvested by inducing a voltage in the receive circuit via resonant inductive coupling between the inductor of the transmit circuit and an inductor of the receive circuit. ### Claim 4 (depends on 1) The method according to claim 1, wherein a mechanical component of the security tag is connected directly between a switch and a receive capacitor of the receive circuit. ### Claim 5 (depends on 1) The method according to claim 1, further comprising: receiving a wireless signal by a transceiver circuit of the security tag; performing operations by a controller of the security tag to selectively close a switch in response to the wireless signal; and causing a release of a mechanical component of the security tag by allowing energy to flow from the receive circuit to the mechanical component when the switch is closed. ### Claim 6 (depends on 5) The method according to claim 5, wherein the energy harvesting is discontinued by the security tag when the switch is closed. ### Claim 7 (depends on 5) The method according to claim 5, further comprising performing operations by the controller to re-open the switch. ### Claim 8 (depends on 7) The method according to claim 7, further comprising harvesting energy once again by the security tag when the switch is open. ### Claim 9 A security tag, comprising: a transceiver circuit that performs communication operations at a communications frequency, the operations including receiving a wireless signal at a communications frequency and receiving energy at an energy harvesting frequency from a transmit circuit of an external device; a receive circuit that facilitates a harvest of energy emitted from the transmit circuit of an external device at an energy harvesting frequency; a switch; a mechanical component; and a controller that performs operations to selectively close a switch in response to the wireless signal, causing a release of the mechanical component of the security tag by allowing energy to flow from the receive circuit to the mechanical component when the switch is closed, wherein the communications frequency is out of band of the energy harvesting frequency. ### Claim 10 (depends on 9) The security tag according to claim 9, wherein the energy harvesting frequency is higher or lower than the communications frequency. ### Claim 11 (depends on 9) The security tag according to claim 9, wherein the energy harvesting is discontinued by the security tag when the switch is closed. ### Claim 12 (depends on 9) The security tag according to claim 9, wherein the controller is further configured to selectively re-open the switch. ### Claim 13 (depends on 12) The security tag according to claim 12, wherein the energy is harvested once again by the security tag when the switch is open. ### Claim 14 (depends on 9) The security tag according to claim 9, wherein the transmit circuit comprises: a capacitor; an inductor connected to a first terminal of the capacitor; and a voltage source coupled a second terminal of the capacitor and tuned to a frequency of the capacitor and inductor. ### Claim 15 (depends on 14) The security tag according to claim 14, wherein the energy is harvested by inducing a voltage in the receive circuit via resonant inductive coupling between the inductor of the transmit circuit and an inductor of the receive circuit. ### Claim 16 (depends on 14) The security tag according to claim 14, wherein a mechanical detachment component of the security tag is connected directly between the switch and a receive capacitor of the receive circuit.