Due to a lack of financial resources, we unfortunately have to suspend the import of any new radio frequency and mobile phone-related articles as of now (November 27, 2017). We apologize for this inconvenience and will keep you informed.

Because we received a large number of inquiries, we set up a bank account to accept donations. With their aid, we hope to resume, at least partly, the import of newly published articles to the RF archive of the EMF-Portal. Any contribution is greatly appreciated. Thank you for your kind support!

DONATION ACCOUNT: Uniklinik RWTH Aachen, IBAN: DE27 3905 0000 0013 0040 15, BIC: AACSDE33, Reference: GB-FM/380454/Arbm



Electromagnetic fields are ubiquitous in our environment. In physics, as light, they belong to the electromagnetic waves. In the electromagnetic spectrum different ranges can be distinguished according to their frequency and wavelength (see also Electromagnetic spectrum).

Frequency f
The frequency is defined as oscillations per second, given in units of Hertz (Hz). 1 Hz corresponds to one complete oscillation per second (1 Hz = 1/s), such as in mechanical oscillations (e.g. vibration, sound waves, and heartbeats) or electromagnetic waves (e.g. light and electromagnetic fields). 2 Hz corresponds to two complete oscillations per second, 3 Hz to three oscillations per second, and so on. The period describes the time, in which one full oscillation takes place (e.g. 1 s at 1 Hz, 0.5 s at 2 Hz, and so on; see figure).

Wavelength λ
The wavelength is defined as the length of one oscillation of an electromagnetic wave (also called length of a “period”), given in units of meters (m).
Frequency and wavelength relate directly to each other: the higher the frequency, the shorter the wavelength (see figure).

The “strength” or “height” of an oscillation is called amplitude (see figure). Depending on the kind of oscillation, different units are used. In the range of electromagnetic fields these are:
Time course of a sinusoidal wave