fresnel zone


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fresnel zone

Pronounced "fraynel zone." The pattern of electromagnetic radiation that is created by a transmitting station from its antenna to receiving antennas. It is in the shape of an ellipsoid, or 3D ellipse, which looks like an elongated football.
References in periodicals archive ?
The optic is a variant of something called a Fresnel zone plate.
InfiPLANNER visualizes the path profile, indicating the first Fresnel zone
For example, while in the classroom, I learned that communications signals experience propagation loss over water, but the training did not address the underlying Fresnel Zone concept (p.
Vassal'lo, "Technological aspects of Fresnel zone reflectors," Advances on Antennas, Reflectors and Beam Control, Chapter 4, 85-114, Research Signpost, 2005, ISBN
A Fresnel zone plate (FZP) is an important optical element with light collecting properties and it has many applications in the visible light, millimeter waves, extreme-UV, and x-ray domain regions [1-6].
The Laser-etched Lenses image type enables the recording of optical components such as Fresnel zone plates which act as real lenses.
Even the best x-ray microscope lenses (concentric circles of metal known as Fresnel zone plates), can't focus x-rays with high efficiency, so to get an image means using such intense radiation that it more quickly damages biological specimens.
As the corresponding effect at the point of observation P is attributable to the central Fresnel zone at Q acting alone, there is no need to know the nature of this aniso-tropy and hence it follows that dU(P) = (i/[lambda])U(Q) exp (ikQP)/QP.
If either the jammer or the desired transmitter are beyond the Fresnel zone, the "two-ray" propagation-loss model applies:
The tech rep responds, "That's good to know, but what about proper Fresnel Zone clearance?
Theta], it does not narrow further, but enters into the Fresnel zone where it is progressively transformed into a plane wave front.
Although the deployment was Near-Line-of-Sight (nLoS), with a partially obstructed fresnel zone, radio and radar interference at and around the airport prevented wireless systems from reliably connecting.