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Wireless & Mobility · Foundational

Reflection

RF bouncing off a smooth surface larger than the wavelength, such as metal or glass.

Definition

Reflection occurs when a wave strikes an object whose dimensions are large compared with the wavelength. Reflections are the main cause of multipath, which degrades older SISO radios but is exploited by MIMO. Metal doors, filing cabinets, and low-E glass are strong reflectors.

Example

A metal warehouse racking system reflects signals creating many multipath paths.

Exam tip

Multipath caused by reflection is harmful to 802.11a/b/g but beneficial to 802.11n and later MIMO.

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