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Radio frequency system

Belongs to:
Electronic Article Surveillance
Description:

Radio frequency systems are electronic article surveillance systems (EAS) and commonly use frequencies between 1.8 and 8.7 MHz. The radiofrequency systems and the acousto-magnetic systems are the most commonly used article surveillance systems. 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).
In case of a radio frequency system, the passive transponder (tag) consists of an electric oscillating circuit with a capacitor and a coil that can only be set to an oscillation at a specific frequency, the so called resonance frequency. When the unpaid good is carried outside the shop, the oscillating circuit is powered by the field of the detectors at the exit. The electromagnetic field of the detector is typically varied harmonically about 10 % around the resonance frequency of the tag. When a tag is led into the field of the detector, a weakening of the field in the detector is measurable. The detection of a tag raises an alarm.
When the good is paid at the checkout counter, a deactivator renders the tag unusable with a strong magnetic field that destroys the capacitor of the oscillating circuit. In consequence, the oscillating circuit is not working anymore and the good can be led through the detector without an alarm.

Frequency ranges:
  • 1.8–8.7 MHz
Type of field:
electric, magnetic, and electromagnetic

Measurements (acc. to literature)

deactivator
Measurand Value Feature Remarks
electric field strength 0.12 V/m (measured) 7.4 - 8.8 MHz detection mode: at a distance of 2.5 cm; continuous, swept frequency [1]
electric field strength 0.13 V/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 50 cm; pulsed, fixed frequency [1]
electric field strength 20 V/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 20 cm; pulsed, fixed frequency [1]
electric field strength 21 V/m (measured) 7.4 - 8.6 MHz detection mode: at a distance of 20 cm; pulsed, frequency stepped [1]
electric field strength 60 V/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 10 cm; pulsed, fixed frequency [1]
electric field strength 89 V/m (measured) 7.4 - 8.6 MHz detection mode: at a distance of 10 cm; pulsed, frequency stepped [2]
electric field strength 89 V/m (maximum) 7.4 - 8.6 MHz pulsed, frquency stepped; at a distance of 10 cm [1]
electric field strength ≤ 1 V/m (measured) 7.4 - 8.8 MHz detection mode: at a distance of 2.5 cm; continuous, swept frequency [1]
magnetic field strength 0.34 A/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 30 cm; pulsed, fixed frequency [1]
magnetic field strength 0.8 A/m (measured) 7.4 - 8.8 MHz deactivation mode: at a distance of 20 cm; pulsed, fixed frequency [1]
magnetic field strength 2.7 A/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 10 cm; pulsed, fixed frequency [1]
magnetic field strength 3 A/m (measured) 7.4 - 8.8 MHz deactivation mode: at a distance of 10 cm; pulsed, fixed frequency [1]
magnetic field strength 3.1 A/m (measured) 7.4 - 8.6 MHz detection mode: at a distance of 10 cm; pulsed, frequency stepped [1]
magnetic field strength 10 A/m (measured) 7.4 - 8.8 MHz deactivation mode: at a distance of 10 cm, pulsed fixed frequency [1]
magnetic field strength 12.3 A/m (measured) 7.4 - 8.6 MHz detection mode: at a distance of 3 cm; pulsed, frequency stepped [1]
magnetic field strength 58 A/m (measured) 7.4 - 8.6 MHz deactivation mode: at a distance of 3 cm; pulsed, fixed frequency [1]
detector
Measurand Value Feature Remarks
electric field strength 1.39 V/m (maximum) 13.56 MHz at a distance of 5 cm [3]
electric field strength 1.5–2 V/m (measured) 8.8 - 10.2 MHz at a distance of approx. 20 cm and a height of 1.3 m [4]
electric field strength 1.8–4.1 V/m (measured) 8.8 - 10.2 MHz at a distance of approx. 20 cm and a height of 1 m [4]
electric field strength 4 V/m (measured) 7.4 - 9.1 MHz at a distance of 10 cm; continuous, swept frequency [1]
electric field strength 4 V/m (maximum) 7.4 - 9.1 MHz at a distance of 10 cm [1]
electric field strength 190 V/m (measured) 7.4 - 8.8 MHz deactivation mode: at a distance of 5 cm; pulsed, fixed frequency [1]
electric field strength ≤ 1 V/m (measured) 7.4 - 8.8 MHz at a distance of 2.5 cm; continuous, swept frequency [1]
electric field strength ≤ 1 V/m (measured) 7.4 - 8.8 MHz at a distance of 2.5 cm for a single antenna; continuous, swept frequency [1]
electric field strength ≤ 1 V/m (maximum) 7.4 - 8.8 MHz with antenna; at a distance of 2.5 cm [1]
current density 0.6 A/m² (maximum) 10 MHz at a height of 140 cm in an adult (distance to the gates: 20 cm) [5]
current density 0.8 A/m² (maximum) 10 MHz at a height of 115 cm in a 150 cm tall child (distance to the gates: 20 cm) [5]
current density 1 A/m² (maximum) 10 MHz at a height of 95 cm in a 125 cm tall child (distance to the gates: 20 cm) [5]
magnetic field strength 0.03 mA/m (measured) 7.4 - 8.8 MHz at a distance of 35 cm; continuous, swept frequency [1]
magnetic field strength 0.031 A/m (maximum, measured) 8.8 MHz Prestigeguard: at a distance of 35 cm to the antenna [6]
magnetic field strength 0.04 A/m (maximum, measured) 8.8 MHz Vezia: at a distance of 50 cm [6]
magnetic field strength 0.06 A/m (measured) 7.7 - 9.4 MHz at a distance of 20 cm [1]
magnetic field strength 0.07 A/m (maximum, measured) 8.7 MHz EQ45: at a distance of 50 cm to the antenna [6]
magnetic field strength 0.07 A/m (maximum, measured) 8.8 MHz Prestigeguard: at a distance of 20 cm to the antenna [6]
magnetic field strength 0.09 A/m (measured) 7.4 - 9.1 MHz at a distance of 15 cm; continuous, swept frequency [1]
magnetic field strength 0.094 A/m (maximum, measured) 8.8 MHz Vezia: at a distance of 35 cm to the antenna [6]
magnetic field strength 0.1–0.2 A/m (measured) 8.8 - 10.2 MHz at a distance of approx. 20 cm and a height of 1 m [4]
magnetic field strength 0.1 A/m (measured) 8.8 - 10.2 MHz at a distance of approx. 20 cm and a height of 1.3 m [4]
magnetic field strength 0.11–0.25 A/m (measured) 13.6 MHz mean value out of 45 measurement points at two different systems; distance: 5 cm [3]
magnetic field strength 0.11 A/m (maximum, measured) 8.2 MHz Evolve G20: at a distance of 50 cm to the antenna [6]
magnetic field strength 0.115 A/m (maximum, measured) 8.8 MHz Prestigeguard: at a distance of 10 cm to the antenna [6]
magnetic field strength 0.12 A/m (maximum, measured) 8.7 MHz EQ45: at a distance of 35 cm to the antenna [6]
magnetic field strength 0.12 A/m (measured) 7.4 - 8.8 MHz at a distance of 15 cm; continuous, swept frequency [1]
magnetic field strength 0.14 A/m (maximum, measured) 8.2 MHz Trend: at a distance of 50 cm to the antenna [6]
magnetic field strength 0.15 A/m (maximum, measured) 8.2 MHz Evolve G20: at a distance of 35 cm to the antenna [6]
magnetic field strength 0.18 A/m (measured) 7.4 - 8.8 MHz single antenna: at a distance of 20 cm; continuous, swept frequency [1]
magnetic field strength 0.2 A/m (maximum) 10 MHz close to a tag deactivating system [1]
magnetic field strength 0.24 A/m (maximum, measured) 8.2 MHz Trend: at a distance of 35 cm to the antenna [6]
magnetic field strength 0.246 A/m (maximum, measured) 8.8 MHz Vezia: at a distance of 20 cm to the antenna [6]
magnetic field strength 0.29 A/m (maximum, measured) 8.7 MHz EQ45: at a distance of 20 cm to the antenna [6]
magnetic field strength 0.37 A/m (maximum, measured) 8.2 MHz Evolve G20: at a distance of 20 cm to the antenna [6]
magnetic field strength 0.39 A/m (measured) 7.4 - 8.8 MHz single antenna: at a distance of 10 cm; continuous, swept frequency [1]
magnetic field strength 0.465 A/m (maximum, measured) 8.8 MHz Vezia: at a distance of 10 cm to the antenna [6]
magnetic field strength 0.59 A/m (maximum, measured) 8.7 MHz EQ45: at a distance of 10 cm to the antenna [6]
magnetic field strength 0.6 A/m (maximum, measured) 8.2 MHz Trend: at a distance of 20 cm to the antenna [6]
magnetic field strength 0.81 A/m (maximum, measured) 8.2 MHz Evolve G20: at a distance of 10 cm to the antenna [6]
magnetic field strength 1.19 A/m (maximum, measured) 8.2 MHz Trend: at a distance of 10 cm to the antenna [6]
magnetic field strength 2 A/m (measured) 7.4 - 8.8 MHz single antenna: at the surface; continuous, swept frequency [1]
magnetic field strength 13 A/m (measured) 13.56 MHz - [7]
magnetic field strength 15 A/m (maximum, measured) 8.8 MHz Prestigeguard: at a distance of 50 cm to the antenna [6]
magnetic flux density 0.3 µT (measured) 4.9 MHz at a distance of 20 cm [8]
magnetic flux density 1 µT (mean, measured) 1.8 - 2.1 MHz measured in 36 cm distance between two antennas in a width of 182.9 cm. [9]
magnetic flux density 2.1 µT (measured) 4.9 MHz at a distance of 10 cm [8]
magnetic flux density 8.4 µT (measured) 4.9 MHz at a distance of 5 cm [8]
magnetic flux density ≤ 1 µT (maximum, measured) 7.2 - 9 MHz measured in 36 cm distance between two antennas in a width of 91.4 cm. [9]
magnetic flux density ≤ 1 µT (maximum, measured) 7.6 - 8.9 MHz measured in 36 cm distance between two antennas in a width of 91.4 cm. [9]
SAR 10.1 µW/kg (maximum) 10 MHz for a 10-year-old child during frontal exposure; averaged over the whole body [5]
SAR 10.5 µW/kg (maximum) 10 MHz for an adult with lateral exposition; averaged over the whole body [5]
SAR 10.7 µW/kg (maximum) 10 MHz for a 10-year-old child during lateral exposure; averaged over the whole body [5]
SAR 12.9 µW/kg (maximum) 10 MHz for a 5-year-old child during lateral exposition; averaged over the whole body [5]
SAR 63.6 µW/kg (maximum, simulated) 13.56 MHz for a standing chinese male with 1.72 m height; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over a cubic mass of 10 g of skin and muscle of the head. [10]
SAR 65.1 µW/kg (maximum, simulated) 13.56 MHz for a lying infant with 0.74 m height at 0.60 m height in a buggy; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over the whole body. [10]
SAR 69.4 µW/kg (maximum, simulated) 13.56 MHz for a chinese male with 1.72m height; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over the whole body. [10]
SAR 84.7 µW/kg (maximum, simulated) 13.56 MHz for a standing child with 1.20m height; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over the whole body. [10]
SAR 88.2 µW/kg (maximum) 10 MHz for an adult during frontal expostition; averaged over the whole body [5]
SAR 129 µW/kg (maximum) 10 MHz for a 5 year-old child during frontal exposition; averaged over the whole body [5]
SAR 0.4 mW/kg (maximum) 10 MHz at a height of 85 cm for a 150 cm tall child (distance to the port: 20 cm); averaged over 10 g of tissue [5]
SAR 0.5 mW/kg (maximum) 10 MHz at a height of 70 cm for a 125 cm tall child (distance to the gates: 20 cm); averaged over 10 g of tissue [5]
SAR 4.26 mW/kg (maximum, simulated) 13.56 MHz for a standing child with 1.20 m height; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over a cubic mass of 10 g of the central nervous system of the head. [10]
SAR 7.13 mW/kg (maximum, simulated) 13.56 MHz for a standing infant with 0.74 m height; distance to the port: 20 cm; scaled on ICNIRP reference levels for general public exposure; SAR averaged over a cubic mass of 10 g of the central nervous system of the head. [10]
not specified
Measurand Value Feature Remarks
magnetic field strength 0.02–0.03 A/m (measured) 7.4 - 8.6 MHz mean value out of 45 measurement points at 2 different systems; distance: 5 cm [3]
magnetic field strength 0.02 A/m (mean, measured) 7.6 - 8.7 MHz mean value out of 45 measurement points at two different systems; distance: 5 cm [3]

References

  1. Swerdlow AJ et al. (2012): Health Effects from Radiofrequency Electromagnetic Fields - RCE 20
  2. Boggio PS et al. (2011): Non-invasive brain stimulation to assess and modulate neuroplasticity in Alzheimer's disease
  3. Trulsson J et al. (2007): Assessment of magnetic fields surrounding electronic article surveillance systems in Sweden
  4. Harris C et al. (2000): Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems
  5. Martinez-Burdalo M et al. (2010): Comparison of SAR and induced current densities in adults and children exposed to electromagnetic fields from electronic article surveillance devices
  6. Schmid G et al. (2012): [Exposure assessement of electromagnetic fields generated by radio frequency identification (RFID) technologies. Project 3609S80002]
  7. Börner F (2011): [Electromagnetic fields generated by plant, machines and equipment]
  8. Cooper TG (2002): Occupational Exposure to Electric and Magnetic Fields in the Context of the ICNIRP Guidelines
  9. Casamento J (1999): Characterizing Electromagnetic Fields of Common Electronic Article Surveillance Systems
  10. Li C et al. (2015): Dosimetry for infant exposures to electronic article surveillance system: Posture, physical dimension and anatomy