Reflection vs. Diffraction: Key Differences Explained

This article explores the differences between reflection and diffraction, two important concepts related to the propagation of electromagnetic (EM) waves, especially in Non-Line-of-Sight (NLOS) communication scenarios. When a signal travels from a transmitter to a receiver, it often encounters obstacles, leading to reflection, diffraction, and penetration of the signal.

Reflection

Reflection occurs when an EM wave bounces off a surface.

Reflection of an EM wave.

In mobile broadband communication, multipath reflection using wide-beam antennas is crucial. Achieving single-path reflection can be challenging because it requires a specific angle of incidence from an object to achieve the desired propagation. Figure 1 illustrates the reflection of an EM signal between a transmitter and a receiver.

Diffraction

Diffraction, sometimes referred to as “bending,” happens when an electromagnetic wave encounters the edge of a building or another large object along its path.

Diffraction of an EM wave.

The signal loss due to diffraction depends on the frequency of the EM wave and the sharpness of the bend. Figure 2 shows the diffraction of an EM signal as it travels between a transmitter and a receiver.

For more information on signal propagation, you can explore the different Wireless Propagation Modes, including groundwave, skywave, and Line-of-Sight (LOS) wave propagation.