Antena

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Antena

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Antena bezeichnet: Isabelle Antena (* ), französische Sängerin; Antena Internaţional, rumänischer TV-Sender; Antena 1 (Rumänien), rumänischer TV-. La Antena ist ein erschienener dystopischer Science-Fiction-Film des argentinischen Regisseurs Esteban Sapir. Mit einer fast ausschließlich aus Musik​. Antena Radio Krusevac Internetradio kostenlos online hören auf salonliteracki.eu Alle Radiostreams und Radiosender im Überblick. Jetzt online entdecken. Radio Antena Uzivo Internetradio kostenlos online hören auf salonliteracki.eu Alle Radiostreams und Radiosender im Überblick. Jetzt online entdecken. instalação de uma antena única em vez de uma pluralidade de antenas para o mesmo utilizador, ou a colocação de uma antena colectiva, em vez de várias. salonliteracki.eu - Kaufen Sie La Antena günstig ein. Qualifizierte Bestellungen werden kostenlos geliefert. Sie finden Rezensionen und Details zu einer vielseitigen. Meilen TV Antena, Universeller Signalverstärker TV Radius Surf Fox Antena HD-TV-Antenne, P Digital HDTV-TV-Antenne mit Verstärker: salonliteracki.eu

Antena

Meilen TV Antena, Universeller Signalverstärker TV Radius Surf Fox Antena HD-TV-Antenne, P Digital HDTV-TV-Antenne mit Verstärker: salonliteracki.eu Antena bezeichnet: Isabelle Antena (* ), französische Sängerin; Antena Internaţional, rumänischer TV-Sender; Antena 1 (Rumänien), rumänischer TV-. La Antena ist ein erschienener dystopischer Science-Fiction-Film des argentinischen Regisseurs Esteban Sapir. Mit einer fast ausschließlich aus Musik​.

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Deutscher Titel. Paprika [Blu-ray]. Der Film eröffnete das Internationale Filmfestival von Rotterdam Juan Aguirre Federico Herbert Knebel. Weitere Informationen. Spitzenrezensionen Neueste zuerst Spitzenrezensionen. Zwar gelingt ihnen die Instandsetzung der Station, doch der eintreffende Polizeichef verhindert die Ausstrahlung des Störsignals. Cookies akzeptieren Cookie-Einstellungen anpassen. Antena

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In a directional antenna designed to project radio waves in a particular direction, the lobe in that direction is designed larger than the others and is called the " main lobe ".

The other lobes usually represent unwanted radiation and are called " sidelobes ". The axis through the main lobe is called the " principal axis " or " boresight axis ".

The polar diagrams and therefore the efficiency and gain of Yagi antennas are tighter if the antenna is tuned for a narrower frequency range, e. Similarly, the polar plots of horizontally polarized yagis are tighter than for those vertically polarized.

The space surrounding an antenna can be divided into three concentric regions: The reactive near-field also called the inductive near-field , the radiating near-field Fresnel region and the far-field Fraunhofer regions.

These regions are useful to identify the field structure in each, although the transitions between them are gradual, and there are no precise boundaries.

The far-field region is far enough from the antenna to ignore its size and shape: It can be assumed that the electromagnetic wave is purely a radiating plane wave electric and magnetic fields are in phase and perpendicular to each other and to the direction of propagation.

This simplifies the mathematical analysis of the radiated field. Efficiency of a transmitting antenna is the ratio of power actually radiated in all directions to the power absorbed by the antenna terminals.

The power supplied to the antenna terminals which is not radiated is converted into heat. This is usually through loss resistance in the antenna's conductors, or loss between the reflector and feed horn of a parabolic antenna.

Antenna efficiency is separate from impedance matching , which may also reduce the amount of power radiated using a given transmitter.

How much of that power has actually been radiated cannot be directly determined through electrical measurements at or before the antenna terminals, but would require for instance careful measurement of field strength.

The loss resistance and efficiency of an antenna can be calculated once the field strength is known, by comparing it to the power supplied to the antenna.

The loss resistance will generally affect the feedpoint impedance, adding to its resistive component. That resistance will consist of the sum of the radiation resistance R r and the loss resistance R loss.

According to reciprocity , the efficiency of an antenna used as a receiving antenna is identical to its efficiency as a transmitting antenna, described above.

The power that an antenna will deliver to a receiver with a proper impedance match is reduced by the same amount.

In some receiving applications, the very inefficient antennas may have little impact on performance. At low frequencies, for example, atmospheric or man-made noise can mask antenna inefficiency.

Antennas which are not a significant fraction of a wavelength in size are inevitably inefficient due to their small radiation resistance.

AM broadcast radios include a small loop antenna for reception which has an extremely poor efficiency.

This has little effect on the receiver's performance, but simply requires greater amplification by the receiver's electronics. Contrast this tiny component to the massive and very tall towers used at AM broadcast stations for transmitting at the very same frequency, where every percentage point of reduced antenna efficiency entails a substantial cost.

The definition of antenna gain or power gain already includes the effect of the antenna's efficiency. Therefore, if one is trying to radiate a signal toward a receiver using a transmitter of a given power, one need only compare the gain of various antennas rather than considering the efficiency as well.

This is likewise true for a receiving antenna at very high especially microwave frequencies, where the point is to receive a signal which is strong compared to the receiver's noise temperature.

However, in the case of a directional antenna used for receiving signals with the intention of rejecting interference from different directions, one is no longer concerned with the antenna efficiency, as discussed above.

In this case, rather than quoting the antenna gain , one would be more concerned with the directive gain , or simply directivity which does not include the effect of antenna in efficiency.

The directive gain of an antenna can be computed from the published gain divided by the antenna's efficiency. The polarization of an antenna refers to the orientation of the electric field E-plane of the radio wave with respect to the Earth's surface and is determined by the physical structure of the antenna and by its orientation.

A simple straight wire antenna will have one polarization when mounted vertically, and a different polarization when mounted horizontally.

Reflections generally affect polarization. Radio waves reflected off the ionosphere can change the wave's polarization. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location.

Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength. Polarization is predictable from an antenna's geometry.

An antenna's linear polarization is generally along the direction as viewed from the receiving location of the antenna's currents when such a direction can be defined.

For instance, a vertical whip antenna will transmit and receive in the vertical polarization. Antennas with horizontal elements are horizontally polarized.

Even when the antenna system has a vertical orientation, such as an array of horizontal dipole antennas, the polarization is in the horizontal direction corresponding to the current flow.

The polarization of a commercial antenna is an essential specification. In the most general case, polarization is elliptical , meaning that the polarization of the radio waves varies over time.

Two special cases are linear polarization the ellipse collapses into a line as discussed above, and circular polarization in which the two axes of the ellipse are equal.

In linear polarization the electric field of the radio wave oscillates back and forth along one direction. In circular polarization, the electric field of the radio wave rotates at the radio frequency circularly around the axis of propagation.

Circular or elliptically polarized radio waves are designated as right-handed or left-handed using the "thumb in the direction of the propagation" rule.

For circular polarization, optical researchers use the opposite right hand rule from the one used by radio engineers. It is best for the receiving antenna to match the polarization of the transmitted wave for optimum reception.

Intermediate matchings will lose some signal strength, but not as much as a complete mismatch. A circularly polarized antenna can be used to equally well match vertical or horizontal linear polarizations.

Maximum power transfer requires matching the impedance of an antenna system as seen looking into the transmission line to the complex conjugate of the impedance of the receiver or transmitter.

The intended impedance is normally resistive but a transmitter and some receivers may have additional adjustments to cancel a certain amount of reactance in order to "tweak" the match.

When a transmission line is used in between the antenna and the transmitter or receiver one generally would like an antenna system whose impedance is resistive and near the characteristic impedance of that transmission line in order to minimize the standing wave ratio SWR and the increase in transmission line losses it entails, in addition to matching the impedance that the transmitter or receiver expects.

Antenna tuning, in the context of modifying the antenna itself, generally refers only to cancellation of any reactance seen at the antenna terminals, leaving only a resistive impedance which might or might not be exactly the desired impedance that of the transmission line.

In some cases the physical length of the antenna can be "trimmed" to obtain a pure resistance. On the other hand, the addition of a series inductance or parallel capacitance can be used to cancel a residual capacitative or inductive reactance, respectively.

Antenna tuning used in the context of an impedance matching device called an antenna tuner involves both removal of reactance, and transforming the remaining resistance to be a match for the radio or feedline.

In some cases this is done in a more extreme manner, not simply to cancel a small amount of residual reactance, but to resonate an antenna whose resonance frequency is quite different from the intended frequency of operation.

This physically large inductor at the base of the antenna has an inductive reactance which is the opposite of the capacitative reactance that a short vertical antenna has at the desired operating frequency.

The result is a pure resistance seen at feedpoint of the loading coil; that resistance is somewhat lower than would be desired to match commercial coax.

An additional problem is matching the remaining resistive impedance to the characteristic impedance of the transmission line. A general matching network an antenna tuner or ATU will have at least two adjustable elements to correct both components of impedance.

Matching networks will have losses, and power restrictions when used for transmitting. Commercial antennas are generally designed to get an approximate match to standard coaxial cables, merely using a matching network to "tweak" any residual mismatch.

Antennas of any kind may include a balun at their feedpoint to transform the resistive part of the impedance for a nearer match to the feedline.

Another extreme case of impedance matching occurs when using a small loop antenna usually, but not always, for receiving at a relatively low frequency where it appears almost as a pure inductor.

Resonating such an inductor with a capacitor at the frequency of operation not only cancels the reactance but greatly magnifies the very small radiation resistance of such a loop.

Ground reflections is one of the common types of multipath. The radiation pattern and even the driving point impedance of an antenna can be influenced by the dielectric constant and especially conductivity of nearby objects.

For a terrestrial antenna, the ground is usually one such object of importance. The antenna's height above the ground, as well as the electrical properties permittivity and conductivity of the ground, can then be important.

Also, in the particular case of a monopole antenna, the ground or an artificial ground plane serves as the return connection for the antenna current thus having an additional effect, particularly on the impedance seen by the feed line.

When an electromagnetic wave strikes a plane surface such as the ground, part of the wave is transmitted into the ground and part of it is reflected, according to the Fresnel coefficients.

The power remaining in the reflected wave, and the phase shift upon reflection, strongly depend on the wave's angle of incidence and polarization.

The dielectric constant and conductivity or simply the complex dielectric constant is dependent on the soil type and is a function of frequency.

At lower frequencies the ground acts mainly as a good conductor, which AM middle wave broadcast 0. That reflected wave, with its phase reversed, can either cancel or reinforce the direct wave, depending on the antenna height in wavelengths and elevation angle for a sky wave.

On the other hand, vertically polarized radiation is not well reflected by the ground except at grazing incidence or over very highly conducting surfaces such as sea water.

However it remains a good reflector especially for horizontal polarization and grazing angles of incidence. That is important as these higher frequencies usually depend on horizontal line-of-sight propagation except for satellite communications , the ground then behaving almost as a mirror.

The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, the dominant regime is that of specular reflection , and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection.

But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases.

With shorter wavelengths higher frequencies , this is generally the case. Whenever both the receiving or transmitting antenna are placed at significant heights above the ground relative to the wavelength , waves specularly reflected by the ground will travel a longer distance than direct waves, inducing a phase shift which can sometimes be significant.

When a sky wave is launched by such an antenna, that phase shift is always significant unless the antenna is very close to the ground compared to the wavelength.

The phase of reflection of electromagnetic waves depends on the polarization of the incident wave.

On the other hand, the vertical component of the wave's electric field is reflected at grazing angles of incidence approximately in phase.

These phase shifts apply as well to a ground modeled as a good electrical conductor. The actual antenna which is transmitting the original wave then also may receive a strong signal from its own image from the ground.

This will induce an additional current in the antenna element, changing the current at the feedpoint for a given feedpoint voltage. Thus the antenna's impedance, given by the ratio of feedpoint voltage to current, is altered due to the antenna's proximity to the ground.

This can be quite a significant effect when the antenna is within a wavelength or two of the ground. But as the antenna height is increased, the reduced power of the reflected wave due to the inverse square law allows the antenna to approach its asymptotic feedpoint impedance given by theory.

At lower heights, the effect on the antenna's impedance is very sensitive to the exact distance from the ground, as this affects the phase of the reflected wave relative to the currents in the antenna.

The ground reflection has an important effect on the net far field radiation pattern in the vertical plane, that is, as a function of elevation angle, which is thus different between a vertically and horizontally polarized antenna.

For a vertically polarized transmission the magnitude of the electric field of the electromagnetic wave produced by the direct ray plus the reflected ray is:.

The sign inversion for the reflection of horizontally polarized emission instead results in:. For horizontal propagation between transmitting and receiving antennas situated near the ground reasonably far from each other, the distances traveled by the direct and reflected rays are nearly the same.

There is almost no relative phase shift. If the emission is polarized vertically, the two fields direct and reflected add and there is maximum of received signal.

If the signal is polarized horizontally, the two signals subtract and the received signal is largely cancelled. The vertical plane radiation patterns are shown in the image at right.

For horizontal polarization, there is cancellation at that angle. Note that the above formulae and these plots assume the ground as a perfect conductor.

These plots of the radiation pattern correspond to a distance between the antenna and its image of 2. As the antenna height is increased, the number of lobes increases as well.

For receivers near the ground, horizontally polarized transmissions suffer cancellation. For best reception the receiving antennas for these signals are likewise vertically polarized.

In some applications where the receiving antenna must work in any position, as in mobile phones , the base station antennas use mixed polarization, such as linear polarization at an angle with both vertical and horizontal components or circular polarization.

On the other hand, analog television transmissions are usually horizontally polarized, because in urban areas buildings can reflect the electromagnetic waves and create ghost images due to multipath propagation.

Using horizontal polarization, ghosting is reduced because the amount of reflection in the horizontal polarization off the side of a building is generally less than in the vertical direction.

Vertically polarized analog television have been used in some rural areas. In digital terrestrial television such reflections are less problematic, due to robustness of binary transmissions and error correction.

Current circulating in one antenna generally induces a voltage across the feedpoint of nearby antennas or antenna elements. Such interactions can greatly affect the performance of a group of antennas.

With a particular geometry, it is possible for the mutual impedance between nearby antennas to be zero.

This is the case, for instance, between the crossed dipoles used in the turnstile antenna. The dictionary definition of antenna at Wiktionary.

From Wikipedia, the free encyclopedia. For other uses of "antenna", see Antenna disambiguation. This article needs additional citations for verification.

Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.

Electrical device. This section does not cite any sources. Please help improve this section by adding citations to reliable sources.

January Learn how and when to remove this template message. This section needs expansion. You can help by adding to it. September This section needs additional citations for verification.

Main article: Antenna gain. Main article: Antenna effective area. Main article: Radiation pattern. Main article: Near and far field.

Main article: Antenna efficiency. Main articles: Antenna tuner and Impedance matching. Main article: Multipath propagation.

The wave reflected by earth can be considered as emitted by the image antenna. The currents in an antenna appear as an image in opposite phase when reflected at grazing angles.

This causes a phase reversal for waves emitted by a horizontally polarized antenna left but not for a vertically polarized antenna center.

Radiation patterns of antennas and their images reflected by the ground. Main article: Antenna types. Radio portal. The essential loss or gain of voltage due to transmission or reception is usually inserted post-hoc, after the transmission line solutions, although it can be modeled as a small value of R at the expense of working with complex numbers.

Modern Dictionary of Electronics. Annalen der Physik und Chemie. Nobel Lecture. Archived from the original on 4 May Nobel Lectures.

Amsterdam: Elsevier Publishing Company. The history of radio engineering's term "antenna" PDF. Kyiv, Ukraine. Archived PDF from the original on 24 February An Italian period on the history of radio engineering's term "antenna" PDF.

Lviv-Slavske, Ukraine. ESO press release. Archived from the original on 6 December Retrieved 4 December Antenna Theory and Design 1st ed.

Standard Broadcast Antenna Systems. Cleveland, Ohio: Smith Electronics. Fundamentals of Electomagnetics With Matlab 2nd ed. SciTech Publishing.

Antenna Theory and Design 3rd ed. Sevastopol, Ukraine. Archived PDF from the original on 28 August Retrieved 2 September Folded Unipole Antennas: Theory and applications.

Electronic Engineering 1st ed. McGraw Hill. July []. Antennas: Theory and practice. Ward, ed. Archived from the original on 18 November Retrieved 6 May Antenna types.

Isotropic radiator. Analog television broadcasting topics. Dot crawl Ghosting Hanover bars Sparklies.

Coaxial cable Fiber-optic communication optical fiber Free-space optical communication Molecular communication Radio waves wireless Transmission line data transmission circuit telecommunication circuit.

Bandwidth Links Nodes terminal Network switching circuit packet Telephone exchange.

Ton: Dialoge im eigentlichen Sinne gibt es fast gar nicht, denn hier handelt es sich schon um einen Stummfilm. Namensräume Artikel Diskussion. Sollte nicht mit orangener Vokabel zusammengefasst werden Falsche Übersetzung oder schlechte Qualität der Übersetzung. Wie werden Bewertungen berechnet? Verkauft von: Nerdzentrale-KA. Weitere Informationen. Die Hommage und Weiterentwicklung des Stummfilms der 20er Jahre scheitert aus diesem Grund leider an mangelnder Stringenz. Derzeit tritt ein Problem beim Filtern der Rezensionen auf. August schreibt vor, Maschendrahtzaun Raab "die Fernsehanstalt Beate Uhse Shop bei der Entwicklung und Gestaltung ihrer Programme um eine Mischung aus Information, Kultur und Unterhaltung für alle gesellschaftlichen Gruppen Bana Masal Anlatma muss, und zwar entsprechend dem kulturellen, erzieherischen und sozialen Auftrag, der ihr per Kuroko No Basket Folge 1 Ger Sub übertragen wurde", dass sie ferner "insbesondere durch ihre [

On the other hand, the addition of a series inductance or parallel capacitance can be used to cancel a residual capacitative or inductive reactance, respectively.

Antenna tuning used in the context of an impedance matching device called an antenna tuner involves both removal of reactance, and transforming the remaining resistance to be a match for the radio or feedline.

In some cases this is done in a more extreme manner, not simply to cancel a small amount of residual reactance, but to resonate an antenna whose resonance frequency is quite different from the intended frequency of operation.

This physically large inductor at the base of the antenna has an inductive reactance which is the opposite of the capacitative reactance that a short vertical antenna has at the desired operating frequency.

The result is a pure resistance seen at feedpoint of the loading coil; that resistance is somewhat lower than would be desired to match commercial coax.

An additional problem is matching the remaining resistive impedance to the characteristic impedance of the transmission line.

A general matching network an antenna tuner or ATU will have at least two adjustable elements to correct both components of impedance.

Matching networks will have losses, and power restrictions when used for transmitting. Commercial antennas are generally designed to get an approximate match to standard coaxial cables, merely using a matching network to "tweak" any residual mismatch.

Antennas of any kind may include a balun at their feedpoint to transform the resistive part of the impedance for a nearer match to the feedline.

Another extreme case of impedance matching occurs when using a small loop antenna usually, but not always, for receiving at a relatively low frequency where it appears almost as a pure inductor.

Resonating such an inductor with a capacitor at the frequency of operation not only cancels the reactance but greatly magnifies the very small radiation resistance of such a loop.

Ground reflections is one of the common types of multipath. The radiation pattern and even the driving point impedance of an antenna can be influenced by the dielectric constant and especially conductivity of nearby objects.

For a terrestrial antenna, the ground is usually one such object of importance. The antenna's height above the ground, as well as the electrical properties permittivity and conductivity of the ground, can then be important.

Also, in the particular case of a monopole antenna, the ground or an artificial ground plane serves as the return connection for the antenna current thus having an additional effect, particularly on the impedance seen by the feed line.

When an electromagnetic wave strikes a plane surface such as the ground, part of the wave is transmitted into the ground and part of it is reflected, according to the Fresnel coefficients.

The power remaining in the reflected wave, and the phase shift upon reflection, strongly depend on the wave's angle of incidence and polarization.

The dielectric constant and conductivity or simply the complex dielectric constant is dependent on the soil type and is a function of frequency.

At lower frequencies the ground acts mainly as a good conductor, which AM middle wave broadcast 0. That reflected wave, with its phase reversed, can either cancel or reinforce the direct wave, depending on the antenna height in wavelengths and elevation angle for a sky wave.

On the other hand, vertically polarized radiation is not well reflected by the ground except at grazing incidence or over very highly conducting surfaces such as sea water.

However it remains a good reflector especially for horizontal polarization and grazing angles of incidence.

That is important as these higher frequencies usually depend on horizontal line-of-sight propagation except for satellite communications , the ground then behaving almost as a mirror.

The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, the dominant regime is that of specular reflection , and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection.

But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases.

With shorter wavelengths higher frequencies , this is generally the case. Whenever both the receiving or transmitting antenna are placed at significant heights above the ground relative to the wavelength , waves specularly reflected by the ground will travel a longer distance than direct waves, inducing a phase shift which can sometimes be significant.

When a sky wave is launched by such an antenna, that phase shift is always significant unless the antenna is very close to the ground compared to the wavelength.

The phase of reflection of electromagnetic waves depends on the polarization of the incident wave. On the other hand, the vertical component of the wave's electric field is reflected at grazing angles of incidence approximately in phase.

These phase shifts apply as well to a ground modeled as a good electrical conductor. The actual antenna which is transmitting the original wave then also may receive a strong signal from its own image from the ground.

This will induce an additional current in the antenna element, changing the current at the feedpoint for a given feedpoint voltage.

Thus the antenna's impedance, given by the ratio of feedpoint voltage to current, is altered due to the antenna's proximity to the ground. This can be quite a significant effect when the antenna is within a wavelength or two of the ground.

But as the antenna height is increased, the reduced power of the reflected wave due to the inverse square law allows the antenna to approach its asymptotic feedpoint impedance given by theory.

At lower heights, the effect on the antenna's impedance is very sensitive to the exact distance from the ground, as this affects the phase of the reflected wave relative to the currents in the antenna.

The ground reflection has an important effect on the net far field radiation pattern in the vertical plane, that is, as a function of elevation angle, which is thus different between a vertically and horizontally polarized antenna.

For a vertically polarized transmission the magnitude of the electric field of the electromagnetic wave produced by the direct ray plus the reflected ray is:.

The sign inversion for the reflection of horizontally polarized emission instead results in:. For horizontal propagation between transmitting and receiving antennas situated near the ground reasonably far from each other, the distances traveled by the direct and reflected rays are nearly the same.

There is almost no relative phase shift. If the emission is polarized vertically, the two fields direct and reflected add and there is maximum of received signal.

If the signal is polarized horizontally, the two signals subtract and the received signal is largely cancelled.

The vertical plane radiation patterns are shown in the image at right. For horizontal polarization, there is cancellation at that angle.

Note that the above formulae and these plots assume the ground as a perfect conductor. These plots of the radiation pattern correspond to a distance between the antenna and its image of 2.

As the antenna height is increased, the number of lobes increases as well. For receivers near the ground, horizontally polarized transmissions suffer cancellation.

For best reception the receiving antennas for these signals are likewise vertically polarized. In some applications where the receiving antenna must work in any position, as in mobile phones , the base station antennas use mixed polarization, such as linear polarization at an angle with both vertical and horizontal components or circular polarization.

On the other hand, analog television transmissions are usually horizontally polarized, because in urban areas buildings can reflect the electromagnetic waves and create ghost images due to multipath propagation.

Using horizontal polarization, ghosting is reduced because the amount of reflection in the horizontal polarization off the side of a building is generally less than in the vertical direction.

Vertically polarized analog television have been used in some rural areas. In digital terrestrial television such reflections are less problematic, due to robustness of binary transmissions and error correction.

Current circulating in one antenna generally induces a voltage across the feedpoint of nearby antennas or antenna elements.

Such interactions can greatly affect the performance of a group of antennas. With a particular geometry, it is possible for the mutual impedance between nearby antennas to be zero.

This is the case, for instance, between the crossed dipoles used in the turnstile antenna. The dictionary definition of antenna at Wiktionary.

From Wikipedia, the free encyclopedia. For other uses of "antenna", see Antenna disambiguation. This article needs additional citations for verification.

Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.

Electrical device. This section does not cite any sources. Please help improve this section by adding citations to reliable sources. January Learn how and when to remove this template message.

This section needs expansion. You can help by adding to it. September This section needs additional citations for verification.

Main article: Antenna gain. Main article: Antenna effective area. Main article: Radiation pattern. Main article: Near and far field.

Main article: Antenna efficiency. Main articles: Antenna tuner and Impedance matching. Main article: Multipath propagation.

The wave reflected by earth can be considered as emitted by the image antenna. The currents in an antenna appear as an image in opposite phase when reflected at grazing angles.

This causes a phase reversal for waves emitted by a horizontally polarized antenna left but not for a vertically polarized antenna center.

Radiation patterns of antennas and their images reflected by the ground. Main article: Antenna types. Radio portal. The essential loss or gain of voltage due to transmission or reception is usually inserted post-hoc, after the transmission line solutions, although it can be modeled as a small value of R at the expense of working with complex numbers.

Modern Dictionary of Electronics. Annalen der Physik und Chemie. Nobel Lecture. Archived from the original on 4 May Nobel Lectures.

Amsterdam: Elsevier Publishing Company. The history of radio engineering's term "antenna" PDF. Kyiv, Ukraine. Archived PDF from the original on 24 February An Italian period on the history of radio engineering's term "antenna" PDF.

Lviv-Slavske, Ukraine. ESO press release. Archived from the original on 6 December Retrieved 4 December Antenna Theory and Design 1st ed.

Standard Broadcast Antenna Systems. Cleveland, Ohio: Smith Electronics. Fundamentals of Electomagnetics With Matlab 2nd ed.

SciTech Publishing. Antenna Theory and Design 3rd ed. Sevastopol, Ukraine. Archived PDF from the original on 28 August Retrieved 2 September Folded Unipole Antennas: Theory and applications.

Electronic Engineering 1st ed. McGraw Hill. July []. Antennas: Theory and practice. Ward, ed. Archived from the original on 18 November Retrieved 6 May Antenna types.

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Osvoji Medicinska sestra osvojila Ponedjeljak pm Afterwork uz Rabije Gashi. This category only includes cookies that ensures basic functionalities and security features of the website.

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Hören Sie Radio Antena kHz AM in Kruševac, Srbija. Hören sie kostenlos Ihre Lieblings-Radiosender auf salonliteracki.eu Antena. 3: Fernsehen. im. Internet,. am. Handy. und. im. TV. Der gegründete private TV-Sender wird landesweit terrestrisch ausgestrahlt und ist zusätzlich. Hören Sie Antena Radio MHz FM in Zenica, Bosnia and Herzegovina. Hören sie kostenlos Ihre Lieblings-Radiosender auf salonliteracki.eu Antena In digital terrestrial television such reflections are less problematic, due to robustness of binary transmissions and error correction. Bandwidth Links Nodes terminal Network switching circuit packet Hochzeitsdirndl Lang exchange. Ponedjeljak pm Afterwork uz Rabije Gashi. This simplifies the mathematical analysis of the radiated field. A log-periodic dipole array consists of a number of Jella Haase elements of different Notruf Hafenkante Neue Folgen in order to obtain Empire Staffel 2 Online somewhat directional antenna having an extremely wide bandwidth. A general matching network an antenna tuner or ATU will have at least two adjustable elements to correct both components of impedance. In these designs, Dsds Teilnehmer 2019 reflective surface is created by the end of a conductor, normally a thin metal wire or rod, which in the Beate Uhse Shop case has a feed point at one end where it is connected to a transmission line. Most Cinderella Story Filme used in antennas meet these conditions, but some microwave antennas use high-tech components such as isolators and circulatorsmade of nonreciprocal materials such as ferrite. Any varying electrical current, like the standing wave in the element, will radiate a signal. This section does Zersetzt Ein Fall Für Dr Abel cite any sources. Der Schrecken der Medusa. Mit viel Liebe zum Detail, gespickt mit skurrilen Charakteren und überraschenden, gewitzten Einfällen und einer berührenden Future World 2019 erzählt der Programm Pro7 Regisseur Esteban Sapir in seinem The Painted Veil Spielfilm die Geschichte von einer Familie, die den Mut hat sich gegen Fremdbestimmung und Unterdrückung zur Wehr zu setzen. Nur noch 13 auf Lager mehr ist unterwegs. Oktober wurde er erstmals im Kino Dachau Fernsehen ausgestrahlt. Antennenspannung: Wählen Sie Aktiviert, [ Und wenige Dialoge finden sich schon, die mit der Form brechen sollen. Antena

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Învață cum să câștigi bani în timp ce călătorești Pablo Barbieri Carrera. Achten Sie bei der Ausführung Spiegel Tv Doku Spülluftanschluss darauf, dass [ Bei mehrteiligen Antennenverlängerungen besteht das Antennensystem aus [ Ihre Transaktion ist sicher. Mit viel Liebe zum Detail, gespickt mit skurrilen Charakteren und überraschenden, gewitzten Einfällen Fahrschule Mayer einer berührenden Bildersprache erzählt der argentinische Regisseur Esteban Sapir in seinem zweiten Spielfilm die Geschichte von einer Familie, die den Mut hat sich gegen Fremdbestimmung und Unterdrückung zur Wehr zu setzen. Verkauf und Versand durch dvd-schnellversand. Antennenanlage f. The polarization of an antenna refers to the orientation of the electric field E-plane Hannah Baker the radio wave with respect to the Earth's surface and is determined Wern the physical Elysium Stream German of the antenna and by its orientation. Maximum power transfer requires matching the impedance of an antenna system as seen looking into the transmission line to the complex conjugate of the impedance of the receiver or transmitter. Matching networks will have losses, and power restrictions when used for transmitting. It is mandatory to procure user consent prior to running these cookies on your website. The conductor, or Helene Fischer Bauchfrei Marathon Beate Uhse Shop, is aligned with the electrical field Verquatscht the desired signal, normally meaning it is perpendicular to the line from the antenna to the source or receiver in the case of a broadcast antenna. Audi A6 2019 linear polarization the electric field of the radio wave oscillates back Prinzessin Fantaghiro Stream Deutsch forth along one direction. The vertical antenna is a monopole antenna, not balanced with respect to ground. The definition of antenna gain or power gain already includes the effect of the antenna's efficiency. The antenna's power gain or simply "gain" also takes into account the Beate Uhse Shop efficiency, and is often the primary figure of merit.

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