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Electromagnetic EAS system

Belongs to:
Electronic Article Surveillance
Description:

Electromagnetic EAS systems are electronic article surveillance (EAS) RFID-systems and commonly use frequencies from the low frequency range between 10 Hz and 20 kHz. As with all EAS systems, a tag is attached to the good which is detected by detectors in the exit area of a shop (see main category Electronic Article Surveillance). The passive transponder (tag) has a soft-magnetic metal stripe that is magnetized by an external field in the exit area of the shop with multiple frequencies. By the magnetization with multiple frequencies, the tag itself emits magnetic fields with other frequencies than the external field. The detectors in the exit area of the shop identify the new frequencies and start an alarm. A deactivator changes the permanent magnetization of the tag by a strong magnetic field, so that the method of detection is not working anymore and the good can be passed through the exit area of the shop.

Frequency ranges:
  • 10 Hz–20 kHz
Type of field:
electric and magnetic

Measurements (acc. to literature)

deactivator
Measurand Value Feature Remarks
electric field strength 1.24 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the brain; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
electric field strength 3.88 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the heart; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
electric field strength 3.93 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the heart; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
electric field strength 4.47 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the prostata; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
electric field strength 12.04 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the intestine; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
electric field strength 13.55 mV/m (maximum, simulated) 200 Hz - [1]
electric field strength 35.31 mV/m (maximum, simulated) 200 Hz averaged over 1 cm² in the intestine; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
electric field strength 35.98 V/m (maximum, simulated) 200 Hz averaged over 1 cm² in the prostata; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
current density 0.1 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the brain; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
current density 0.3 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the brain; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
current density 1.89 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the prostata; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
current density 1.94 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the heart; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
current density 6.3 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the intestine; male model (height: 176.4 cm) in front of a 85 cm high table; C-shaped core [1]
current density 6.78 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the heart; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
current density 15.18 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the prostata; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
current density 18.47 mA/m² (maximum, simulated) 200 Hz averaged over 1 cm² in the intestine; male model (height: 176.4 cm) in front of a 85 cm high table; bar-type device [1]
magnetic flux density 0.43–1.6 µT (measured) 5 - 7.5 kHz at a height of 0.5 - 1.7 m at the cashier's seat in a supermarket [2]
magnetic flux density 0.6–0.96 µT (measured) 5 - 7.5 kHz at a height of 0.5 - 1.7 m at the cashier's seat in a small market [2]
magnetic flux density 2–3 µT (measured) 5 - 7.5 kHz at a height of 0.5 - 1.7 m at the cashier's seat in a exhibition hall [2]
magnetic flux density 3 µT (measured) 5 - 7.5 kHz at a height of 0.5 - 1.7 m at the cashier's seat in a library [2]
detector
Measurand Value Feature Remarks
magnetic field strength 20–47 A/m (mean, measured) 5 and 7.5 kHz mean value of 45 measurement points at two different systems: distance: 20 cm [3]
magnetic field strength 26 A/m (mean, measured) 6.25 kHz mean value of 45 measurement points at one system; distance: 20 cm [3]
magnetic field strength 55–98 A/m (mean, measured) 10 Hz mean value out of 45 measurement points of three different systems; distance: 20 cm [3]
magnetic field strength 138–228 A/m (mean, measured) 220 Hz mean value out of 45 measurement points at two different systems; distance: 20 cm [3]
magnetic field strength 20 A/m (maximum, measured) 6.3 kHz measured at and between the antennas of EAS systems [6]
magnetic field strength 115.4–218.1 A/m (measured) 218 - 530 Hz at a distance of approx. 20 cm and a height of 1.3 m [7]
magnetic field strength 181.8–587.4 A/m (measured) 218 - 530 Hz at a distance of approx. 20 cm and a height of 1 m [7]
magnetic flux density 7–33 µT (measured) 5 - 7.5 kHz at a distance of 0.2 m from the gates in a supermarket [2]
magnetic flux density 7–38 µT (measured) 5 - 7.5 kHz in the middle of the gates at a height of 0.8 - 1.7 m in a supermarket [2]
magnetic flux density 10–28 µT (measured) 5 - 7.5 kHz in the middle of the gates at a height of 0.8 - 1.7 m in an exhibition hall [2]
magnetic flux density 13–21 µT (measured) 5 - 7.5 kHz in the middle of the gates at a height of 0.8 - 1.7 m in a library [2]
magnetic flux density 14–79 µT (measured) 5 - 7.5 kHz at a distance of 0.2 m from the gates in an exhibition hall [2]
magnetic flux density 16–30 µT (measured) 5 - 7.5 kHz at a distance of 0.2 m from the gates in a library [2]
magnetic flux density 34–46 µT (measured) 5 - 7.5 kHz in the middle of the gates at a height of 0.8 - 1.7 m in a small market [2]
magnetic flux density 38 µT–58 T (measured) 5 - 7.5 kHz at a distance of 0.2 m to the gates in a small market [2]
magnetic flux density 39 µT (measured) 6.25 kHz at a distance of 45 cm to the detector (sinusoidal continuous wave) [4]
magnetic flux density 43 µT (measured) 5 and 7.5 kHz at a distance of 48.5 cm to the detector (continuous wave) [4]
magnetic flux density 58 µT (measured) 6.25 kHz at a distance of 25.7 cm to the detector (continuous wave) [4]
magnetic flux density 72 µT (mean, measured) 536 Hz measured in 36 cm distance between two antennas in a width of 73.1 cm. [5]
magnetic flux density 72 µT (measured) 535.7 Hz at a distance of 36 cm to the detector (sinusoidal continuous wave) [4]
magnetic flux density 93 µT (measured) 230 Hz at a distance of 42 cm to the detector (sinusoidal continuous wave) [4]
magnetic flux density 100 µT (measured) 1 kHz at a distance of 41 cm to the detector (pulsed modulated sinusoid) [4]
magnetic flux density 122 µT (mean, measured) 219 Hz measured in 36 cm distance between two antennas in a width of 81.3 cm. [5]
magnetic flux density 122 µT (measured) 219 Hz at a distance of 36 cm to the detector (sinusoidal continuous wave) [4]
magnetic flux density 146 µT (measured) 73 Hz at a distance of 31.5 cm to the detector (sinusoidal continuous wave) [4]
magnetic flux density 1.2 mT (maximum) 218 Hz measured at and between the antennas of EAS systems [6]

References

  1. Li Q et al. (2005): Calculation of magnetic field-induced current densities for humans from EAS countertop activation/deactivation devices that use ferromagnetic cores
  2. Roivainen P et al. (2014): Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems
  3. Trulsson J et al. (2007): Assessment of magnetic fields surrounding electronic article surveillance systems in Sweden
  4. No authors listed (2007): Extremely Low Frequency Fields
  5. Casamento J (1999): Characterizing Electromagnetic Fields of Common Electronic Article Surveillance Systems
  6. Börner F (2011): [Electromagnetic fields generated by plant, machines and equipment]
  7. Harris C et al. (2000): Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems