When a radio wavebends around an obstaclein its path, this phenomenon is calleddiffraction. Diffraction allows the RF signal to reach areas that are not in the direct line of sight of the transmitter, such as behind walls, corners, or other obstructions. The amount of bending depends on the wavelength of the signal relative to the size of the obstacle—longer wavelengths (lower frequencies) diffract more effectively than shorter wavelengths.

This property is crucial in wireless network design, especially in enterprise or mesh deployments, because it enables coverage in complex indoor environments and around obstructions where direct line-of-sight communication is impossible. Diffraction differs from other RF phenomena:absorption(option A) occurs when RF energy is partially absorbed by materials, reducing signal strength;diffusion(option B) refers to scattering of the signal in multiple directions; andreflection(option C) occurs when RF waves bounce off surfaces like walls or ceilings, which can lead to multipath interference.

Cisco wireless design guides emphasize understanding diffraction forcoverage planning, AP placement, and optimizing signal propagationin indoor and campus deployments, ensuring that signals can adequately reach shadowed or obstructed areas without excessive loss or dead spots. Reference topic:RF Fundamentals — diffraction, reflection, absorption, and indoor wireless propagation.