New search

RFID

Belongs to:
Security and identification systems
Synonyms:
Radio Frequency Identification
Description:

RFID systems (radio frequency identification) are used for contactless identification and tracking of objects with electromagnetic fields. They basically consist of a tag on an object and a reader to read and write data on the tag. There are several applications, these include for example: ID cards, electric locks, ski passes, toll systems or animal identification systems. Depending on the application, the manufacturer and the technology, different frequencies are used. However, the frequencies (see below) fall within the freely-accessable ISM bands.

Electronic article surveillance systems (EAS) are RFID systems, too. For reasons of clarity, the measurements on EAS systems are placed in an own seperate category. EAS systems are often called one-bit RFID systems as long only the presence of a tag is detected. More-bit systems transmit, for example, an identification number of the tag but can be utilized as an EAS system, too.

RFID tags are distinguished between active and passive: The active tag makes use of a battery to gain higher transition distances (up to kilometers) and faster communication. The passive tag powered by external magnetic fields is smaller and cheaper. A reader (alternatively called a detector, equipped with transmitting/receiving antennas) receives fields that are emitted by the tag and can, as the case may be, energize the passive tag.

Frequency ranges:
  • 120 kHz
  • 125 kHz
  • 134 kHz
  • 4.9 MHz
  • 13.56–40 MHz
  • 433.92 MHz
  • 866 MHz
  • 2.45 GHz
Type of field:
electric, magnetic, and electromagnetic

Measurements (acc. to literature)

reader
Measurand Value Feature Remarks
electric field strength 0.02 V/m (maximum, measured) 2450 MHz rod antenna (length: 10.5 cm, diameter: 0.9 cm) at a distance of 10 cm [1]
electric field strength 0.4 V/m (maximum, measured) 433 MHz patch antenna (15.7 x 5.5 x 3 cm) according to ISO 18000-7 at a distance of 10 cm [1]
electric field strength 1 V/m (maximum, measured) 2450 MHz rod antenna (length: 11 cm; diameter: 0.8 cm) at a distance of 10 cm [1]
electric field strength 36.2 V/m (maximum, measured) 915 MHz patch antenna (48.5 x 31 x 5 cm) according to ISO 18000-6B at a distance of 10 cm [1]
electric field strength 79.3 V/m (maximum, measured) 915 MHz patch antenna (31 x 31 x 4.8 cm) according to ISO 18000-6B at a distance of 10 cm [1]
electric field strength 97.3 V/m (maximum, measured) 915 MHz patch antenna (21 x 21 x 3.5 cm) according to ISO 18000-6C at a distance of 10 cm [1]
magnetic field strength 4.6–8.8 A/m (maximum) 13.56 MHz at a distance of 2.5 cm [2]
magnetic field strength 4.9 A/m (maximum, measured) 13.56 MHz rectangular loop (20 x 20 x 0.8 cm) according to ISO 18000-3 mode 1 at a distance of 2.5 cm [1]
magnetic field strength 5.3–0.02 A/m (maximum) 13.56 MHz at a distance of 0 - 30 cm [3]
magnetic field strength 8.8 A/m (maximum, measured) 13.56 MHz rectangular loop (31 x 31 x 2.8 cm) according to ISO 18000-3 mode 1 at a distance of 2.5 cm [1]
magnetic field strength 13.3 A/m (maximum, measured) 0.125 MHz rectangular loop (114 x 66 x 6.3 cm) at a distance of 2.5 cm [1]
magnetic field strength 18.6 A/m (maximum, measured) 13.56 MHz patch antenna (21 x 32 x 1.2 cm) according to ISO 18000-3 mode 2 at a distance of 2.5 cm [1]
magnetic field strength 68–269 A/m (measured) 134 kHz at a distance of 2.5 cm [2]
magnetic field strength 162 A/m (maximum, measured) 0.134 MHz rectangular loop (85 x 50 x 5 cm) according to ISO 11785 at a distance of 2.5 cm [1]
magnetic field strength 269 A/m (maximum, measured) 0.134 MHz rectangular loop (20 x 20 x 2.5 cm) according to ISO 11785 at a distance of 2.5 cm [1]
magnetic flux density 10 µT (measured) 120 kHz at a distance of 12 cm [4]
magnetic flux density 20 µT (maximum, measured) 125 kHz at a distance of 7.5 cm [5]
magnetic flux density 20 µT (measured) 120 kHz at a distance of 7.5 cm [4]
SAR 0.6 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 100 mm to the pelvis; computer model of a 14-year-old boy (weight: 50.4 kg, height: 1.69 m) [6]
SAR 0.8 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 100 mm to the head; computer model of a 14-year-old boy (weight: 50.4 kg; height: 1.69 m) [6]
SAR 0.8 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 100 mm to the pelvis; computer model of a 37-year-old man (weight: 72.4 kg, height: 1.77 m) [6]
SAR 1.1 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 100 mm to the head; computer model of a 26-year-old woman, 9 months pregnant (weight: 64.9 kg; height: 1.63 m) [6]
SAR 1.4 W/kg (simulated) 868 - 915 MHz averaged ober 10 g, at a distance of 100 mm to the head; computer model of an 11-year-old girl (weight: 35.4 kg; height: 1.47 m) [6]
SAR 1.9 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 10 mm to the pelvis; computer model of a 37-year-old man (weight: 119.6 kg, height: 1.82 m) [6]
SAR 2.2 W/kg 868 - 915 MHz averaged over 10 g, at a distance of 100 mm to the pelvis; computer model of a 6-year-old boy (weight: 19.3 kg, height: 1.17 m) [6]
SAR 2.45 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 10 mm to the head; computer model of a 6-year-old boy (weight: 19.3 kg, height:1.17 m) [6]
SAR 3.15 W/kg (measured) 868 - 915 MHz averaged over 10 g, at a distance of 10 mm to the head; computer model of an 11-year-old girl (weight: 135.4 kg; height: 1.47 m) [6]
SAR 3.9 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 10 mm to the pelvis; computer model of an 11-year-old girl (weight: 35.4 kg at a height of 1.47 m) [6]
SAR 4.6 W/kg (simulated) 868 - 915 MHz averaged ober 10 g, at a distance of 10 mm to the head; computer model of a 34-year-old man (weight: 72.4 kg, height: 1.82 m) [6]
SAR 6.1 W/kg (simulated) 868 - 915 MHz averaged over 10 g, at a distance of 10 mm to the pelvis; computer model of a 6-year-old boy (weight: 19.3 kg, height: 1.17 m) [6]
power 1.6 W (maximum) not specified with patch antenna; at a distance of 2.5 cm [2]
power 10 W (maximum) not specified with loop antenna; output power at a distance of 2.5 cm [2]
tag
Measurand Value Feature Remarks
electric field strength 17.5 V/m (maximum, simulated) not specified at the wrist of a newborn for mother-child identification at hospitals [7]
SAR 0.35 µW/kg (calculated) 433 MHz Personnel Tag TG 501: female model, active tag inside the breast pocket; transmission power: 0.5 mW; duty cycle: 0.008 [8]
SAR 0.92 µW/kg (calculated) 433 MHz Personnel Tag TG 501: male model, active tag inside the trouser pants; power: 0.5 mW; duty cycle: 0.008 [8]
SAR 0.94 µW/kg (calculated) 433 MHz Personnel Tag TG 501: male model, active tag inside the breast pocket; transmit power: 0.5 mW; duty cycle: 0.008 [8]
SAR 3.28 µW/kg (calculated) 868 MHz active UHF Beacon Tag i-B2 M: female model, tag inside the breast pocket, power: 0.4 mW; duty cycle: 0.002 [8]
SAR 3.41 µW/kg (calculated) 2.45 GHz SYTAG245-2C: female model, active tag inside the breast pocket; power: 1mW; duty cycle: 0.0007 [8]
SAR 5.24 µW/kg (measured) 2.45 GHz SYTAG245-2C: male model, active tag inside the trouser pocket; power: 1 mW; duty cycle: 0.0007 [8]
SAR 7.88 µW/kg (calculated) 868 MHz active UHF Beacon Tag i-B2 M: male model, tag inside the chest pocket; power: 0.4 mW; duty cycle: 0.002 [8]
SAR 10.4 µW/kg (calculated) 2.45 GHz SYTAG245-2C: male model, active tag inside the chest pocket; power: 1 mW; duty cycle: 0.0007 [8]
SAR 19.44 µW/kg (calculated) 868 MHz active UHF Beacon Tag i-B2 M: male model, tag inside the trouser pocket; power: 0.4 mW; duty cycle: 0.002 [8]
power 2–4 W (maximum) 868 MHz - [9]

References

  1. Pantchenko OS et al. (2011): Electromagnetic compatibility of implantable neurostimulators to RFID emitters
  2. Seidman SJ et al. (2010): In vitro tests reveal sample radiofrequency identification readers inducing clinically significant electromagnetic interference to implantable pacemakers and implantable cardioverter-defibrillators
  3. Hamnerius Y (2009): Measurements of human exposure from emerging wireless technologies
  4. Cooper TG (2002): Occupational Exposure to Electric and Magnetic Fields in the Context of the ICNIRP Guidelines
  5. Moser M et al. (2006): [Non-ionizing radiation and health protection in Switzerland: basic information]
  6. Markakis I et al. (2013): Numerical exposure assessment of an RFID reader
  7. Fiocchi S et al. (2011): Computational exposure assessment of electromagnetic fields generated by an RFID system for mother--newborn identity reconfirmation
  8. Schmid G et al. (2012): [Exposure assessement of electromagnetic fields generated by radio frequency identification (RFID) technologies. Project 3609S80002]
  9. van der Togt R et al. (2008): Electromagnetic interference from radio frequency identification inducing potentially hazardous incidents in critical care medical equipment