How do radio waves travel through the air?

Propagation of radio waves

Radio waves (RF stands for Radio Frequency) propagate in straight lines in several directions. The propagation speed of waves in a vacuum is 3.108 m/s.

In any other medium, the signal is weakened by
– reflection
– refraction
– diffraction
– absorption


Absorption of radio waves

When a radio wave encounters an obstacle, part of its energy is absorbed and transformed into energy, part continues to propagate in an attenuated manner and part may eventually be reflected.


Reflection of radio waves

When a radio wave encounters an obstacle, all or part of the wave is reflected, with a loss of power.

The reflection is such that the angle of incidence is equal to the angle of reflection.


Properties of media

Air None Open space, courtyard
Wood Low Door, floor, partition
Plastic Low Partition
Glass Low Non tinted glass
Verre teinté Medium Vitres teintées
Water Medium Aquarium, fountain
Living beings Medium Crowd, animals, humans, vegetation
Bricks Medium Walls
Plaster Medium Partitions
Ceramic High Tiles
Paper High Paper rolls
Concrete High Load-bearing walls, floors, pillars
Armoured glass High Bulletproof glass
Metal Very high Reinforced concrete, mirrors, metal cabinet, lift shaft