Fresnel zone
![Fresnel zone: D is the distance between the transmitter and the receiver; r is the radius of the first Fresnel zone (n=1) at point P. P is d1 away from the transmitter, and d2 away from the receiver.](/Images/godic/202501/14/FresnelSVG1.svg3331.png")
![](/Images/godic/202501/14/1st_Fresnel_Zone_Avoidance3331.png")
![Several examples of how the Fresnel zone can be disrupted.](/Images/godic/202501/14/Fresnel_zone_disrupted3331.png")
A Fresnel zone (/freɪˈnɛl/ fray-NEL), named for physicist Augustin-Jean Fresnel, is a series of concentric ellipsoidal regions of alternating double strength and half strength volumes of a wave's propagation, caused by a wave following multiple paths as it passes by an object and is partially refracted by it, resulting in constructive and destructive interference as the different length paths go in and out of phase.