Related Experiment Video
Updated: Jul 19, 2026
06:43
Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band
Published on: May 2, 2018
Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.
1US Food and Drug Administration, Winchester Engineering and Analytical Center, MA 01890, USA.
Health Physics
|December 23, 1999
Summary
Electronic article surveillance (EAS) systems may emit electromagnetic energy that interferes with medical devices. Measurements show EAS fields exceed medical device safety standards, particularly from pulsed magnetic resonant systems.
Area of Science:
- Biomedical Engineering
- Electromagnetics
- Medical Device Safety
Background:
- Electronic article surveillance (EAS) systems are widely used to prevent retail theft.
- Concerns exist regarding potential electromagnetic interference (EMI) from EAS systems affecting sensitive electronic medical devices.
- The Food and Drug Administration (FDA) is responsible for medical device safety and effectiveness.
Purpose of the Study:
- To quantify electromagnetic field strengths emitted by various EAS systems.
- To assess the potential for EMI between EAS systems and electronic medical devices.
- To provide data for mitigating EMI risks.
Main Methods:
- In situ measurements of electric and magnetic fields around four types of EAS systems (audio frequency magnetic, pulsed magnetic resonant, radio frequency, microwave).
- Comparison of measured field strengths with International Electrotechnical Commission (IEC) medical device standards.
- Analysis of EAS signal modulation schemes for EMI potential.
Main Results:
- Measured magnetic fields reached up to 1073.6 Am(-1) and electric fields up to 23.8 Vm(-1).
- These levels significantly exceed the 3 Vm(-1) standard for medical devices.
- Pulsed magnetic resonant EAS systems exhibit modulation schemes more likely to cause EMI.
Conclusions:
- EAS systems can generate electromagnetic fields exceeding medical device safety limits.
- The findings highlight a significant risk of EMI between EAS and electronic medical devices.
- Quantitative data are crucial for developing mitigation strategies and ensuring patient safety.
Related Concept Videos
01:24The Electromagnetic Spectrum
Electromagnetic waves are categorized according to their wavelengths and frequencies, giving the electromagnetic spectrum. These waves are classified as radio, infrared, ultraviolet, etc. Radio waves refer to electromagnetic radiation with wavelengths ranging from millimeters to kilometers. Radio waves are commonly used for audio communications (i.e., radios) and typically result from an alternating current in the wires of a broadcast antenna. They cover a broad wavelength range and are used...
01:22Intensity Of Electromagnetic Waves
The energy transport per unit area per unit time, or the Poynting vector, gives the energy flux of an electromagnetic wave at any specific time. For a plane electromagnetic wave with E0 and B0 as the peak electric and magnetic fields and traveling along the x-axis, the time-varying energy flux can be given by the following equation:
01:31Electromagnetic Fields
Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by time-varying magnetic fields. While the former is a conservative field, implying that no net work is done on a test charge if it goes around in a complete loop in the field, the latter is, by definition, not a conservative field; net work is done, and it is proportional to the rate of change of magnetic flux.
However, the observation of Gauss's...
However, the observation of Gauss's...
01:20Atomic Emission Spectroscopy: Overview
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
01:26Applications of EMF Measurements
Electromotive force (EMF) measurements have a broad range of applications in various fields, including chemistry and physics. The electrochemical series, an arrangement of elements in order of their standard electrode potentials, can be determined through EMF measurements. Elements with lower standard potentials can reduce ions of elements with higher standard potentials.The standard cell potential, E°, allows for the calculation of the standard reaction Gibbs energy, ΔG°, and the equilibrium...
01:30Electronic Distance Measuring Instruments
Electronic Distance Measuring Instruments (EDMs) are essential tools in modern surveying, offering precise distance measurements by emitting electromagnetic signals and calculating the time required for these signals to travel to a target and return. Two primary types of signals are used in EDMs — light waves and microwaves — each suited to specific environmental and distance requirements. Light-wave-based EDMs utilize either infrared or laser light, providing high accuracy over short distances...