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What is radio emission
Radiation is defined as energy propagated through free space.
Radiation may be characterized according to the energy levels
released, as follows:
● Ionizing radiation (which carries enough or sufficient energy to
ionize and modify the structure of atoms or molecules, e.g., X-
rays).
● Non-ionizing radiation (which does not carry enough energy to
ionize atoms or molecules, e.g., radio waves). Radio waves are
non-ionizing electromagnetic waves with frequencies below those
of visible light, X-rays or gamma rays.
The radiation level emitted by a cellular handset
When using a cellular telephone, the head of the user is locally
highly exposed to radio waves. The level of exposure to RF
emissions by cellular telephones is based on a measuring unit
called SAR (Specific Absorption Rate), which indicates the rate at
which radiant energy is absorbed by a unit of biological mass (such
as the human body) when exposed to a radio-frequency
electromagnetic field. SAR is expressed in W/kg or mW/g.
Manufacturers perform laboratory SAR level tests of complete,
fully functional handsets. The actual SAR level emitted by the
cellular telephone varies. Generally speaking, the closer the
cellular handset is to the base station antenna, the lower the SAR
level. SAR levels are higher the further the cellular telephone is
from the antenna, and in locations where the reception signal is
weak.
The SAR measuring process is highly complex and there are only
few laboratories worldwide that specialize in measuring SAR.
Manufacturers of cellular telephones are compelled to have their
products undergo stringent SAR measurements (for maximum
transmission capacity) and comply with the American or European
Guidelines on SAR. The highest SAR level measured must be
specified.
Due to the complexity of the measurements, no periodical SAR
tests are performed for cellular telephone devices. The SAR level
may change during the product maintenance life and deviation
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