Smart Card? A Study of ElectroMagnetic Fields Produced by RFID Transmitters

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Updated on Jan 29, 2014



Radio Frequency Identification (RFID) is a ubiquitous form of Near Field Communication (NFC) technology that has been adapted by numerous industries to identify items, goods, and people. RFID systems operate through a transmitter, which constantly releases pulses of ElectroMagnetic energy. When a card is placed within range of the transmitter, the energy found in the ElectroMagnetic Field (EMF) powers the card, enabling the card to execute the requested command and send the result back to the transmitter. As RFID technology is becoming more integrated into our daily lives (office buildings, shipment tracking, theft prevention, passports, credit cards, transportation systems, etc.), it is even more important to understand the possible health risks from the EMF emitted by RFID transponders. This experiment tested the EMF to determine the overall safety of these devices. A TriField 100XE meter was placed adjacent to the transmitter to record the strength of the field before, during, and after RFID cards were scanned by various transmitters. At the conclusion of the experiment, 16 different transponders were tested in 6 different systems, and a total of 80 samples were collected.

Based upon various EMF studies, hazardous biological effects have been shown to begin occurring between 1.75 and 5 MilliGausses (MG); the average result of these studies is around 3 MG. Prior to scanning, no device exceeded the most extreme hazardous estimate of 1.75 MG (the average of the devices was 1.3408 MG). However, during and after the scan, every device exceeded the most conservative hazardous estimate of 5 MG (the average of the devices was 15.7792 MG). From this data, it can be determined that, while completely safe when not in use, the combination of the RFID transmitter and card can cause harmful biological effects (such as cancer and brain damage) from ElectroMagnetic radiation. Thus, if one wishes to minimize their exposure to EMFs (and thus, EMF radiation), they should focus on avoiding the alreadyubiquitous, yet somewhat unknown, RFID system.


Physical Science


11th Grade

Project Difficulty




Safety Issues

The only possible safety issue is the exposure to the ElectroMagneitc fields produced by the RFID transmitter (as shown by the US Department of Energy study of EMFs and the US Environmental Protection Agencyʼs report attempting to classify EMFs as Carcinogens). However, since exposure to this device is ubiquitous (and since the device can not be tested without exposing oneʼs self to the EMF) safety precautions were neither plausible nor possible.

Time Taken to Complete Project

Approximately four weeks were spent on research, ten weeks on experimentation, and four weeks on analysis, explanations, and presentations.


The purpose of the project was to measure the ElectroMagnetic Fields produced by RFID (Radio Frequency Identification) transmitters. Using this information, one could determine the safety risks (and properly understand the tradeoffs) of repeated RFID transmitter use.


  • Radio Frequency Identification (RFID) Transmitters
  • RFID Smart Cards
  • TriField 100XE ElectoMagnetic Field Meter
  • Computer Spreadsheet


Radio Frequency Identification (RFID) is a ubiquitous form of Near Field Communication (NFC) technology. Used in Credit Cards, Passports, ID Cards, and Theft Prevention systems, RFID sensors are able to transmit data through a Power - Transmit - Receive (PTR) process. This process begins with the transmitter, which sends an electromagnetic pulse to the RFID card. Using the electricity in the pulse, the card powers itself and begins the transmission process. The transmission process consists of the transmitter sending a command to the card. The card receives the command and executes the appropriate action. This cycle repeats until all data has been properly transmitted.

While RFID technology has many practical applications, exposure to high levels of ElectroMagnetic Fields (EMFs), such as those found in RFID systems, have been shown to cause numerous biological effects (as described in the discussion section). While the exact point where biological effects begin to occur is unknown, the average is around 3 MG (the most extreme is 1.75 MG; the most conservative is 5 MG). This experiment measured the ElectroMagnetic Fields (as measured in MilliGausses - 10-7 Teslas - by a TriField 100XE meter) produced by these RFID systems at various stages of the transmission process. Using this data, one will be able to properly understand any risks associated with RFID technologies.

The study tested various RFID sensors. These include two separate ScholarChip systems (used as an identification system and attendance tracker throughout the School District of Philadelphia), the Delaware River Port Authority PATCO High-Speed Lineʼs Freedom Fare System, multiple office building sensors (found in the offices above Amtrakʼs 30th Street Station), as well as the Massachusetts Bay Transportation Authority (MBTA, or, “The T”) Charlie Card fare system.

Terms and Concepts for Background Research

Near Field Communication - A low-power method of transmitting data at a short range. Radio Frequency Identification - The most common form of Near Field Communication. ElectroMagnetic Field - A magnetic field through which electricity is transmitted.

Research Question

  • What is the strength of the ElectroMagnetic Field produced by RFID transmitters?
  • What are the health effects of exposure to high levels of ElectroMagnetic Fields?
  • What is considered a high level of ElectroMagnetic Fields?


  1. Turn on the TriField 100XE ElectoMagnetic Field Meter and set range to 0-3 milligausses. Place adjacent to RFID transmitter and record the reading.
  2. Scan the RFID card and record the new EMF reading. Should the reading be greater than 3 MG, change the scale to 0-100 MG and repeat. Record the reading.
  3. Record the location of the RFID sensor and the type of RFID card used.
  4. Repeat numerous times for additional accuracy.


When not in use, the RFID Transmitters will produce an ElectroMagnetic Field that is slightly lower than the average safety limit of 3 milligausses. However, after scanning, the RFID Transmitters will produce an ElectroMagnetic Field that is slightly greater than the average safety limit of 3 milligausses.

Experimental Design

The independent variable was the RFID transmitter; the dependent variable was the ElectroMagnetic field produced by the RFID device. The testing materials, such as RFID Cards, were kept the same throughout the experiment. For a control, the TriField 100XE meter was calibrated using a known EMF source (such as a computer monitor) to check the machineʼs ability to accurately calculate the deviceʼs EMF. The data was measured in milligausses (equal to 10-7 Teslas). Data was measured and recorded in the Data Logbook.


Note: The graphs above shows the results, once averaged, for the before and during/after tests. This is separated by device. The shaded gray region represents the suspected range wherein dangerous biological effects can occur. The dark line corresponds with 3 MG, the point at which most scientists believe EMF-related effects begin.


Based on the data, both hypotheses were proven wrong. Prior to scanning the cards, no device surpassed even the most extreme EMF danger measurement (which states that biological effects begin to occur at 1.75 MG). Thus, when not in use, the RFID Transmitters produced a magnetic field that was completely safe. During the scan of the cards, every device surpassed even the most conservative EMF danger measurement (which states that biological effects begin to occur at 5 MG). Thus, when scanning an RFID card, the ElectroMagnetic Field produced by the RFID Transmitter was dangerous and known to cause biological effects.

Experimental Future

There are many possible future adaptations of this experiment. One possible study could directly measure the radiation (as measured in Specific Absorption Rate, or, SAR) from EMFs. This would directly explain why various biological effects occur from exposure to various ElectroMagnetic Fields. In addition, testing other EMF sources (such as microwaves and cell phones) could determine, as some have claimed, whether exposure to EMFs through RFID devices is negligible when compared to these other sources.

Resources and References

Arumugam, Darmindra D., and Daniel W. Engels. "Impacts of RF Radiation on the Human Body in a Passive RFID Environment." Thesis. University of Texas at Arlington, Texas, USA, 2009. Web. 10 Jan. 2011.

Brown, Dennis E. RFID Implementation. New York: McGraw-Hill Communications, 2007. Print.

Bonsor, Kevin, and Candace Keener. "How RFID Works." Howstuffworks. Discovery Network. Web. 10 Jan. 2011.

Department of Energy. Study of Biological Effects Caused by ElectroMagnetic Fields. Rep. Washington, DC: United States Department of Energy, 1989. Print.

"Electric & Magnetic Fields." National Institute of Environmental Health Sciences (NIEHS). Web. Mar. 2011. . "Electric And Magnetic Field (EMF) Radiation from Power Lines." US Environmental Protection Agency. Web. Mar. 2011.