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Generic block diagram of a wireless power system. Wireless power transfer (WPT; also wireless energy transmission or WET) is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, an electrically powered transmitter device generates a time-varying electromagnetic field that transmits ...
The Fresnel equations give the ratio of the reflected wave's electric field to the incident wave's electric field, and the ratio of the transmitted wave's electric field to the incident wave's electric field, for each of two components of polarization. (The magnetic fields can also be related using similar coefficients.)
The transmission coefficient is a measure of how much of an electromagnetic wave (light) passes through a surface or an optical element. Transmission coefficients can be calculated for either the amplitude or the intensity of the wave. Either is calculated by taking the ratio of the value after the surface or element to the value before.
The combined transmission and distribution network is part of electricity delivery, known as the electrical grid. Efficient long-distance transmission of electric power requires high voltages. This reduces the losses produced by strong currents. Transmission lines use either alternating current (AC) or direct current (DC).
Intensity (physics) In physics and many other areas of science and engineering the intensity or flux of radiant energy is the power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy. [a] In the SI system, it has units watts per square metre (W/m 2), or kg ⋅ s −3 in ...
The broken magenta line shows the cumulative power transmission within radius r, half of which flows inside the geometric mean of R 1 and R 2. The center conductor is held at voltage V and draws a current I toward the right, so we expect a total power flow of P = V · I according to basic laws of electricity. By evaluating the Poynting vector ...
e. Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated primarily by wind passing over the sea's surface and also by tidal forces, temperature variations, and ...
Antenna (radio) In radio engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). [1][2] It is the interface between radio waves propagating through space and electric currents ...