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Verfügbare Sprachen
Verfügbare Sprachen
BIS U Basic Manual
8
Reflection, Dispersion and Adsorption of Electromagnetic Waves
8.3 Attenuation of
It is well-known from low-frequency RFID systems that waves permeate all electrically non-
Electromagnetic
conductive materials virtually without loss. On UHF systems, a different approach must be
Radiation
adopted when assessing the behavior of waves penetrating materials.
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Solids or liquids that are comprised of polar molecules and contain water or carbonic
substances, for example, present a high degree of RF attenuation and significantly weaken
the radiation emitted by the antenna. This information confirms that objects such as the
human body represents an insurmountable obstacle for the propagation of electromagnetic
waves.
Mineral oils, on the other hand, only weaken electromagnetic waves to an extremely limited
extent because they consist of non-polar molecules. As a result, for instance, SmartLabels
can be affixed directly to plastic mineral oil containers.
UHF waves cannot penetrate metallic surfaces or grid structures consisting of metallic rods
or mesh. This group also includes metal reinforced concrete walls.
Electrically non-conductive, dry materials such as plastic, paper and wood are penetrated
virtually without loss.
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