【FAQ】What is the wave absorbing, reflecting, shadowing and multipath effect for a radio signal transmission?

Wave Absorption is the effect that the microwave signal during transmission will be absorbed by the soft material which in dimension is equal to or greater than the wave length of signal to decrease the signal strength. If the antenna was mounted in last autumn, then in spring the newly growing leaves will absorb the radio waves. The Rain Attenuation is also a kind of usual phenomenon of wave absorption. The wave length formula is λ＝ v / f　(λ- wave length,  v - velocity, f - frequency).

Wave Reflection is the effect that microwave signal strikes the hard obstacle during transmission to make the wave being reflected back. Too many times of reflection to decrease signal strength and cause the communication unstable.

Shadowing is the signal unreachable area blocked by building due to the radio wave LOS (Line of Sight) transmission character. If the receiver antenna is in the shadow area, the arriving signal is too weak to be received. It is better to mount the antenna to the higher and edger position on the top of building as possible.

Multipath Effect is caused by the signal reflection during transmission. Radio signal transmitted to receiver will take many reflection paths in addition to the straight path. These signals transmission along reflection paths arrive receiver antenna at different times and have different phases than the signal along straight line, therefore, they interfere each other at antenna and result in code error and transmission delay.