# US 2021/0241592 A1 · System and method for foil detection using millimeter wave for retail applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241592 A1 - Document ID: US20210241592A1 - Status: Published application - Kind: A1 - Application number: 17/162,689 - Filed: 2021-01-29 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Sensormatic Electronics Corporation - Applicants: Sensormatic Electronics, LLC - Inventors: John A. ALLEN; Michael Del Busto - Web page: https://patentgrep.com/patent/US20210241592A1 ## CPC - G08B 13/2468: {Antenna in system and the related signal processing} - G08B 13/248: {EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system} - G08B 13/2402: {Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting (mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03)} - G08B 13/2451: {Specific applications combined with EAS} - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS ## Abstract In an aspect, the present disclosure includes a system for detecting metal foil using millimeter wave (mmWave) for retail applications. The system comprises one or more pedestals positioned to define an exit portal leading to a point of exit, one or more security tag readers, fixedly positioned with the one or more pedestals, configured to read data from a security tag passing through the exit portal and one or more mmWave receivers, fixedly positioned near the point of exit, configured to receive one or more reflected mmWave beams from metal foil, wherein the detection of metal foil results in an alert message. ## Claims ### Claim 1 A system for detecting metal foil using millimeter wave (mmWave) for retail applications, comprising: one or more pedestals positioned to define an exit portal leading to a point of exit; one or more security tag readers, fixedly positioned with the one or more pedestals, configured to read data from a security tag approaching the exit portal; and one or more mmWave receivers, fixedly positioned near the point of exit, configured to receive one or more reflected mmWave beams from metal foil, wherein the detection of metal foil results in an alert message. ### Claim 2 (depends on 1) The system of claim 1, further comprising one or more mmWave transmitters configured to transmit one or more incident mmWave beams toward the metal foil. ### Claim 3 (depends on 2) The system of claim 2, wherein the one or more mmWave receivers is further configured to compare the one or more incident mmWave beams and the one or more reflected mmWave beams. ### Claim 4 (depends on 3) The system of claim 3, wherein comparing comprises comparing at least one of transmitter amplitudes, transmitter phases, transmitter frequencies, or transmitter frequency shifts of the one or more incident mmWave beams and at least one of receiver amplitudes, receiver phases, receiver frequencies, or receiver frequency shifts of the one or more reflected mmWave beams. ### Claim 5 (depends on 1) The system of claim 1, wherein the one or more mmWave receivers is further configured to detect the metal foil based on a received signal strength of the one or more reflected mmWave beams. ### Claim 6 (depends on 5) The system of claim 5, wherein detecting the metal foil comprises: comparing the received signal strength to a threshold; and generating the alarm message in response to the received signal strength being larger than the threshold. ### Claim 7 A method of detecting metal foil, comprising: transmitting one or more incident mmWave beams toward the metal foil; receiving one or more reflected mmWave beams; detecting the metal foil based on the one or more reflected mmWave beams; and generating an alarm in response to detecting the metal foil. ### Claim 8 (depends on 7) The method of claim 7, wherein detecting the metal foil further comprises comparing the one or more incident mmWave beams and the one or more reflected mmWave beams. ### Claim 9 (depends on 8) The method of claim 8, wherein comparing further comprises comparing at least one of transmitter amplitudes, transmitter phases, transmitter frequencies, or transmitter frequency shifts of the one or more incident mmWave beams and at least one of receiver amplitudes, receiver phases, receiver frequencies, or receiver frequency shifts of the one or more reflected mmWave beams. ### Claim 10 (depends on 7) The method of claim 7, wherein detecting the metal foil comprises detecting the metal foil based on a received signal strength of the one or more reflected mmWave beams. ### Claim 11 (depends on 10) The method of claim 10, wherein detecting the metal foil further comprises comparing the received signal strength to a threshold. ### Claim 12 A non-transitory computer readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to: cause one or more mmWave transmitters to transmit one or more incident mmWave beams toward the metal foil; cause one or more mmWave receivers to receive one or more reflected mmWave beams; detect metal foil based on the one or more reflected mmWave beams; and generate an alarm in response to detecting the metal foil. ### Claim 13 (depends on 12) The non-transitory computer readable medium of claim 12, wherein the instructions for detecting the metal foil further comprises instructions for comparing the one or more incident mmWave beams and the one or more reflected mmWave beams. ### Claim 14 (depends on 13) The method of claim 13, wherein the instructions for comparing further comprises instructions for comparing at least one of transmitter amplitudes, transmitter phases, transmitter frequencies, or transmitter frequency shifts of the one or more incident mmWave beams and at least one of receiver amplitudes, receiver phases, receiver frequencies, or receiver frequency shifts of the one or more reflected mmWave beams. ### Claim 15 (depends on 12) The method of claim 12, wherein the instructions for detecting the metal foil comprises instructions for detecting the metal foil based on a received signal strength of the one or more reflected mmWave beams. ### Claim 16 (depends on 15) The method of claim 15, wherein the instructions for detecting the metal foil further comprises instructions for comparing the received signal strength to a threshold.