Electromagnetic Field (EMF)
An electromagnetic field is a physical field produced by moving electric charges, consisting of coupled electric and magnetic components that propagate as waves through space.
What is Electromagnetic Field (EMF)?
An electromagnetic field (EMF) is a physical field produced by electrically charged particles. It has two coupled components — an electric field (measured in volts per meter, V/m) and a magnetic field (measured in amperes per meter, A/m, or as magnetic flux density in tesla) — that together carry energy through space as electromagnetic waves.
EMFs span an enormous range of frequencies, collectively called the electromagnetic spectrum. At the low end sit static fields and extremely low frequency (ELF) fields from power lines and electronic circuitry. Higher up are radio frequency (RF) fields used by Wi-Fi, cellular, and Bluetooth radios. Above that are microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
EMFs are categorized as either non-ionizing (below ultraviolet) or ionizing (ultraviolet and above). Non-ionizing radiation does not have enough photon energy to remove electrons from atoms; the dominant biological interaction at typical exposures is heating. Ionizing radiation can break chemical bonds and damage DNA directly.
Exposure limits are set by national and international bodies. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) publishes guidelines covering 0 Hz to 300 GHz. In the United States, the Federal Communications Commission (FCC) regulates RF exposure under 47 CFR §1.1310, which is itself based on IEEE C95.1 and earlier NCRP recommendations.
For consumer electronics, the relevant EMF concerns are RF fields from wireless radios and ELF magnetic fields from circuitry close to the body.
Why does Electromagnetic Field (EMF) matter?
What is an electromagnetic field in simple terms?
An electromagnetic field is the invisible energy field around any electrical current or radio transmitter. It has electric and magnetic parts that travel together as waves, the same physical phenomenon as light, just at different frequencies.
Are EMFs harmful?
It depends on frequency and intensity. Non-ionizing EMFs from consumer electronics are regulated by exposure limits set by ICNIRP and the FCC. Within those limits, established acute effects (mainly tissue heating) are not expected. Long-term, low-level effects remain an active area of research.
How is EMF measured?
Electric fields are measured in V/m, magnetic fields in A/m or tesla, and the combined power density of an electromagnetic wave in W/m² (or mW/cm²). RF survey meters and broadband field probes are the standard instruments.
How RADIHALT relates to Electromagnetic Field
RADIHALT designs EMF protection blankets built around woven copper-nickel Faraday fabric. The terminology on this page — from Faraday-cage physics through attenuation figures and ICNIRP exposure limits — is what underpins the engineering and the claims we publish about our products.
We try to keep our marketing language tied to the same vocabulary regulators and physicists use. If a definition on this page conflicts with anything on a RADIHALT product page, the glossary entry is the source we hold ourselves to.
Related terms
Radio Frequency (RF) Radiation
Radio frequency radiation is the portion of the electromagnetic spectrum between about 3 kHz and 300 GHz, used by Wi-Fi, cellular, broadcast, and radar systems.
Non-Ionizing Radiation
Non-ionizing radiation is electromagnetic radiation whose photons lack the energy to ionize atoms or molecules, encompassing the spectrum from static fields up to most of the ultraviolet band.
ICNIRP Guidelines
ICNIRP — the International Commission on Non-Ionizing Radiation Protection — publishes the exposure guidelines for non-ionizing radiation that most countries adopt as the basis for national regulations.
Power Density (W/m²)
Power density is the amount of electromagnetic power passing through a unit area perpendicular to the direction of propagation, expressed in watts per square meter (W/m²).
From definitions to a real shielding blanket.
RADIHALT applies the physics on this page in a portable, washable copper-nickel Faraday blanket. Starting at $22.