Transmission medium

Transmission Medium

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Transmission medium

A transmission medium (plural transmission media) is a material substance (solid

Solid

A solid object is in the states of matter characterized by resistance to deformation and changes of volume. In other words, it has high values both of Young's modulus and of shear modulus; this contrasts e.g....
, liquid

Liquid

Liquid is one of the principal states of matter. A liquid is a fluid that has the particles loose and can freely form a distinct surface at the boundaries of its bulk material....
or gas

Gas

In physics, a gas is a state of matter, consisting of a collection of particles without a definite shape or volume that are in more or less random motion....
) which can propagate

Wave propagation

Wave propagation is any of the ways in which wave s travel.With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves....
energy

Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
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....
s. For example, the transmission medium for sound

Sound

Sound is vibration transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a threshold of hearing to be heard, or the sensation stimulated in organs of hearing by such vibrations....
received by the ears is usually air, but solids and liquids may also act as transmission media for sound.

The absence of a material medium (the vacuum

Vacuum

A vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty," but in reality, no volume of space can ever be perfectly empty....
of empty space) can also be thought of as a transmission medium for electromagnetic waves such as light

Light

Light, or visible light, is electromagnetic radiation of a wavelength that is Visible spectrum to the human eye , or up to 380?750 nm. In the broader field of physics, light is sometimes used to refer to electromagnetic radiation of all wavelengths, whether visible or not....
and radio wave

Radio Wave

Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s.

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Encyclopedia

A transmission medium (plural transmission media) is a material substance (solid

Solid

Liquid

Liquid is one of the principal states of matter. A liquid is a fluid that has the particles loose and can freely form a distinct surface at the boundaries of its bulk material....
or gas

Gas

In physics, a gas is a state of matter, consisting of a collection of particles without a definite shape or volume that are in more or less random motion....
) which can propagate

Wave propagation

Energy

Wave

Sound

Vacuum

Light

Radio Wave

Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s. While material substance is not required for electromagnetic waves to propagate, such waves are usually affected by the transmission media through which they pass, for instance by absorption

Absorption (electromagnetic radiation)

In physics, absorption of electromagnetic radiation is the way by which the energy of a photon is taken up by matter, typically the electrons of an atom....
or by reflection

Reflection

Reflection or reflexion may refer to:...
or refraction

Refraction

Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one optical medium to another....
at the interface

Interface (chemistry)

An interface is a surface forming a common boundary among two different phase , such as an insoluble solid and a liquid, two immiscible liquids or a liquid and an insoluble gas....
s between media.

The term transmission medium can also refer to the technical device which employs the material substance to transmit or guide the waves. Thus an optical fiber or a copper cable can be referred to as a transmission medium.

A transmission medium can be classified as a:

Linear medium, if different waves at any particular point in the medium can be superposed
Superposition principle

In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems,So that if input A produces response X and input B produces response Y then input produces response ....
;
Bounded medium, if it is finite in extent, otherwise unbounded medium;
Uniform medium or homogeneous medium, if its physical properties are unchanged at different points;
Isotropic medium, if its physical properties are the same in different directions.

Electromagnetic radiation

Electromagnetic radiation takes the form of wave propagation waves in a vacuum or in matter. EM radiation has an electric field and magnetic field component which oscillate in phase perpendicular to each other and to the direction of energy Wave propagation....
can be transmitted through an optical media, such as optical fiber

Optical fiber

An optical fiber is a glass or plastic fiber that carries light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers....
, or through twisted pair

Twisted pair

Twisted pair cabling is a form of wiring in which two conductors are twisted together for the purposes of canceling out electromagnetic interference from external sources; for instance, electromagnetic radiation from unshielded twisted pair cables, and crosstalk between neighboring pairs....
wires, coaxial cable

Coaxial cable

Coaxial cable is a cable consisting of an inner conductor, surrounded by a tubular insulating layer typically made from a flexible material with a high dielectric constant, all of which is then surrounded by another conductive layer , and then finally covered again with a thin insulating layer on the outside....
, or dielectric

Dielectric

A dielectric is a nonconducting substance, i.e. an Insulator . The term was coined by William Whewell in response to a request from Michael Faraday....
-slab waveguide

Waveguide

A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguide for each type of wave....
s. It may also pass through any physical material which is transparent to the specific wavelength

Wavelength

In physics, wavelength is the distance between repeating units of a propagating wave of a given frequency. It is commonly designated by the Greek language letter lambda ....
, such as water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
, air

AIR

Air is the part of Earth's atmosphere that humans breath and as such Air .Air may also refer to:...
, glass

Glass

Glass generally refers to a Hardness, brittle, transparency amorphous solid, such as that used for windows, many Glass Bottles, or eyewear, including, but not limited to, soda-lime glass, borosilicate glass, acrylic glass, sugar glass, Muscovite , or aluminium oxynitride....
, or concrete

Concrete

Concrete is a construction material composed of cement as well as other cementitious materials such as fly ash and slag cement, construction aggregate , water , and Chemistry admixtures....
. Sound

Sound

Sound is vibration transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a threshold of hearing to be heard, or the sensation stimulated in organs of hearing by such vibrations....
is, by definition, the vibration of matter, so it requires a physical medium for transmission, as does other kinds of mechanical waves and heat

Heat

In physics and thermodynamics, heat is any transfer of energy from one body or thermodynamic system to another due to a difference in temperature....
energy. Historically, various aether theories

Aether theories

Alchemy, natural philosophy, and early modern physics proposed the existence of a medium of the ?ther , a space-filling substance or field, thought to be necessary as a transmission medium....
were used in science and thought to be necessary to explain the transmission medium. However, it is now known that electromagnetic waves do not require a physical transmission medium, and so can travel through the "vacuum

Vacuum

Free space

In classical physics, free space is a concept of electromagnetic theory, corresponding to a theoretically perfect vacuum, and sometimes referred to as the vacuum of free space....
. Regions of the insulative

Electrical insulation

An insulator, also called a dielectric, is a material that resists the flow of electric current. An insulating material has atoms with tightly bonded valence electrons....
vacuum can become conductive for electrical conduction

Electrical conduction

Electrical conduction is the movement of electric charge particles through a transmission medium . The movement of charge constitutes an Current ....
through the presence of free electrons, holes

Electron hole

An electron hole is the conceptual and mathematical opposite of an electron, useful in the study of physics and chemistry. The concept describes the lack of an electron....
, or ion

Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
s.

Telecommunications

Many transmission media are used as a communications channel.

For telecommunications purposes in the United States

United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
, 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....
, transmission media are classified as one of the following:

Guided (or bounded) - Waves are guided along a solid medium such as 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....
.
Wireless (or unguided) - Transmission
Transmitter

For biologic transmitters, see transmitter substance.A transmitter is an Electronics machine which, usually with the aid of an antenna , propagates an electromagnetic radiation Signalling such as radio, television, or other telecommunications....
and reception
Receiver (radio)

This article is about a radio receiver, for other uses see Radio .A radio receiver is an electronics circuit that receives its input from an antenna , uses electronic filters to separate a wanted radio signal from all other signals picked up by this antenna, electronic amplifier it to a level suitable for further processing, and finally...
are achieved by means of an antenna
Antenna (radio)

An 'antenna' is a transducer designed to transmitter or receive Electromagnetic radiations. In other words, antennas convert electromagnetic waves into electrical currents and vice versa....
.

Wireless media may carry surface waves or skywave

Skywave

Skywave is the Radio propagation of radio waves bent back to the Earth's surface by the ionosphere. As a result of skywave propagation, a Broadcasting signal from a distant AM broadcasting station at night, or from a shortwave radio station can sometimes be heard as clearly as local stations....
s, either longitudinal

Longitudinal wave

Longitudinal waves are waves that have vibrations along or parallel to their direction of travel; that is, waves in which the motion of the medium is in the same direction as the motion of the wave....
ly or transverse

Transverse wave

A transverse wave is a moving wave that consists of oscillations occurring perpendicular to the direction of energy transfer. If a transverse wave is moving in the positive x-direction, its oscillations are in up and down directions that lie in the y-z plane....
ly, and are so classified.

Transmission medium

Telecommunications

See also