Fresnel zone



  • For transmitted electromagnetic radiation, one of a series of concentric areas in space which surround the path between a transmitter and receiver. The first Fresnel zone encompasses all paths 14 wavelength longer than the line of sight path, the second 1 wavelength longer than the line-of-sight path, the third 1 1/2 wavelengths longer, and so on. Odd-numbered zones are lobes, while even numbered zones are nulls. Utilized, for instance, to describe the concentric ellipsoids between transmitting and receiving microwave antennas.