Absorption occurs when an electromagnetic wave passes through a medium and converts into heat, weakening the wireless signal. The resulting weakening is called attenuation. section 18.1.2 section 18.5
Account for absorption when evaluating wireless coverage:
- Dense walls can absorb enough energy to prevent devices on the opposite side from receiving a coherent signal. section 18.1.2
- Higher-frequency wireless signals are generally more susceptible to absorption by obstacles. section 18.2.1
- Lower frequencies generally penetrate obstacles better and cover larger distances, although they typically provide lower transfer rates. section 18.2.1
Figure 18.4 Phenomena affecting the behavior of electromagnetic waves include absorption by a medium, reflection off surfaces, refraction (bending) as waves pass through a medium, diffraction around obstacles, and scattering from irregularities.
Compare absorption with reflection, refraction, diffraction, and scattering as electromagnetic waves encounter media and obstacles. section 18.1.2
