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His research group at Harvard spent the 1940s and 1950s developing the theory of antenna, using the cylindrical antenna as a boundary value problem subject to Maxwell's equations. Also, scattering and diffraction of electromagnetic waves from spheres, cylinders, strips, and disks, conducted within earth, under water or in tissue. [ 5 ]
Friis' original idea behind his transmission formula was to dispense with the usage of directivity or gain when describing antenna performance. In their place is the descriptor of antenna capture area as one of two important parts of the transmission formula that characterizes the behavior of a free-space radio circuit.
Forms of the reciprocity theorems are used in many electromagnetic applications, such as analyzing electrical networks and antenna systems. [1] For example, reciprocity implies that antennas work equally well as transmitters or receivers, and specifically that an antenna's radiation and receiving patterns are identical.
The journal covers research on antenna technology and propagation of electromagnetic waves.It also contains topical reviews, and perspective articles. It was established in 2020, with Konstantina Nikita (National Technical University of Athens) as the founding editor-in-chief.
Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by antenna directivity (D) which is expressed mathematically as: =.
The directivity is defined as the ratio of the maximum signal strength S radiated by the antenna to the signal strength S iso radiated by the isotropic antenna = Since the directional antenna radiates most of its power into a small solid angle around the z-axis its maximum signal strength is much larger than the isotropic antenna which spreads ...
The two-rays ground-reflection model is a multipath radio propagation model which predicts the path losses between a transmitting antenna and a receiving antenna when they are in line of sight (LOS). Generally, the two antenna each have different height. The received signal having two components, the LOS component and the reflection component ...
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