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Reflection coefficient
 
 
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The reflection coefficient is used in physics
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
 and electrical engineering
Electrical engineering

Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism....
 when wave
Wave

A wave is a disturbance that propagates through space and time, usually with transference of energy. While a mechanical wave exists in a medium , waves of electromagnetic radiation can travel through vacuum, that is, without a medium....
 propagation in a medium containing discontinuities is considered. A reflection coefficient describes either the amplitude
Amplitude

Amplitude is the magnitude of change in the oscillating variable, with each oscillation, within an oscillating system. For instance, sound waves are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation....
 or the intensity of a reflected
Reflection (physics)

Reflection is the change in direction of a wavefront at an wiktionary:interface between two differentmedium so that the wavefront returns into the medium from which it originated....
 wave relative to an incident wave. The reflection coefficient is closely related to the transmission coefficient
Transmission coefficient

The transmission coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuity is considered....
.

Different specialties have different applications for the term.

Telecommunications
In telecommunication
Telecommunication

Telecommunication is the assisted Transmission of Signal over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, Drum , Semaphore line, flag signals or heliograph....
s, the reflection coefficient is the ratio
Ratio

A ratio is an expression which compares quantities relative to each other. The most common examples involve two quantities, but in theory any number of quantities can be compared....
 of the amplitude of the reflected wave to the amplitude of the incident wave.






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The reflection coefficient is used in physics
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
 and electrical engineering
Electrical engineering

Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism....
 when wave
Wave

A wave is a disturbance that propagates through space and time, usually with transference of energy. While a mechanical wave exists in a medium , waves of electromagnetic radiation can travel through vacuum, that is, without a medium....
 propagation in a medium containing discontinuities is considered. A reflection coefficient describes either the amplitude
Amplitude

Amplitude is the magnitude of change in the oscillating variable, with each oscillation, within an oscillating system. For instance, sound waves are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation....
 or the intensity of a reflected
Reflection (physics)

Reflection is the change in direction of a wavefront at an wiktionary:interface between two differentmedium so that the wavefront returns into the medium from which it originated....
 wave relative to an incident wave. The reflection coefficient is closely related to the transmission coefficient
Transmission coefficient

The transmission coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuity is considered....
.

Different specialties have different applications for the term.

Telecommunications


In telecommunication
Telecommunication

Telecommunication is the assisted Transmission of Signal over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, Drum , Semaphore line, flag signals or heliograph....
s, the reflection coefficient is the ratio
Ratio

A ratio is an expression which compares quantities relative to each other. The most common examples involve two quantities, but in theory any number of quantities can be compared....
 of the amplitude of the reflected wave to the amplitude of the incident wave. In particular, at a discontinuity in a transmission line
Transmission line

A transmission line is the material Transmission medium or structure that forms all or part of a Course from one place to another for directing the transmission of energy, such as electromagnetic waves or acoustic waves, as well as electric power transmission....
, it is the complex
Complex number

In mathematics, the complex numbers are an extension of the real numbers obtained by adjoining an imaginary unit, denoted i, which satisfies:...
 ratio of the electric field
Electric field

In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field ....
 strength of the reflected wave to that of the incident wave . This is typically represented with a (capital gamma
Gamma

Gamma is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. It was derived from the Phoenician alphabet Gimel ....
) and can be written as:

The reflection coefficient may also be established using other field or circuit
Electronic circuit

An electronic circuit is a closed path formed by the interconnection of electronic components through which an electric current can flow. The electronic circuits may be physically constructed using any number of methods....
 quantities.

The reflection coefficient can be given by the equations below, where is the impedance
Electrical impedance

Electrical impedance, or simply impedance, describes a measure of opposition to a sinusoidal alternating current . Electrical impedance extends the concept of Electrical resistance to AC circuits, describing not only the relative amplitudes of the voltage and Electric current, but also the relative Phase ....
 toward the source, is the impedance toward the load
External electric load

If an electrical network has a well-defined output terminal, the circuit connected to this terminal is the load. Load affects the performance of circuits that output volts or Current s, such as sensors, voltage sources, and amplifiers....
:

The absolute magnitude
Absolute value

In mathematics, the absolute value of a real number is its numerical value without regard to its Negative and non-negative numbers. So, for example, 3 is the absolute value of both 3 and -3....
 of the reflection coefficient (designated by vertical bars) can be calculated from the standing wave ratio
Standing wave ratio

In telecommunications, standing wave ratio is the ratio of the amplitude of a partial standing wave at an antinode to the amplitude at an adjacent node , in an electrical transmission line....
, :

The reflection coefficient is displayed graphically using a Smith chart
Smith chart

The Smith Chart, invented by Phillip Hagar Smith , is a graphical aid or nomogram designed for electrical engineering specializing in radio frequency engineering to assist in solving problems with transmission lines and impedance matching circuits....
.

Source: from Federal Standard 1037C
Federal Standard 1037C

Federal Standard 1037C, entitled Telecommunications: Glossary of Telecommunication Terms is a United States Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended....
 in support of MIL-STD-188
MIL-STD-188

MIL-STD-188 is a series of U.S. military standards relating to telecommunications....


Seismology


See: reflection seismology
Reflection seismology

Reflection seismology is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflection seismic waves....
Reflection coefficent is used in feeder testing for reliability of medium.

Optics

In optics
Optics

Optics is the study of the behavior and properties of light including its optical phenomena with matter and its imaging by optical instruments....
, intensity and amplitude reflection coefficients are used. Typically, the former are represented by a capital R, while the latter are represented by a lower-case r.

Semipermeable membranes

The reflection coefficient in semipermeable membranes relates to how such a membrane can reflect solute particles from passing through. A value of zero results in all particles passing through. A value of one is such that no particle can pass. It is used in the Starling equation
Starling equation

The Starling equation is an equation that illustrates the role of hydrostatic pressure and oncotic pressure forces in the movement of fluid across capillary....
.

Power cables in high-power electrical drives

The reflection cofficient characterizes an amplitude of voltage reflections between motor and inverter.

External links

  • A flash program that shows how a reflected wave is generated , the reflection coefficient and VSWR