style float right wiktionary antenna Tocright Antenna pl. antennas in radio TV, antennae in biology may refer to Science and engineering Antenna radio , also known as an aerial, a transducer designed to transmit or receive electromagnetic e.g. TV or radio waves Television antenna or TV aerial , is an antenna ... of two colliding galaxies NGC 4038 and NGC 4039 Technology Antenna tower , a tall designed ... antenna , a simple antenna usually constructed from two wires in opposite phases placed end to end Directional antenna , or beam antenna, radiates greater power primarily in one direction Horn antenna , a type of directional antenna shaped like a horn Metamaterial antenna , a class of antenna incorporating metamaterials to increase performance of a miniaturized electrically small antenna systems Omnidirectional antenna , an antenna system which radiates power uniformly in all directions in one plane Parabolic antenna , an antenna shaped like a parabola in one or both planes Biology Antenna biology ... present in most cell types of eukaryotes Antenna journal , the journal of the Royal Entomological Society Entertainment Antenna band , an American indie rock band active from 1991 to 1994, formed in Bloomington ... by Isabelle Antena a pseudonym for Isabelle Powaga . Antenna Cave In album Antenna Cave In album , the third studio album and first major label album by American rock band Cave In, released in 2003 Antenna GO GO 7188 album Antenna GO GO 7188 album , the seventh studio album by Japanese rock band GO GO 7188, released in 2009 Antenna ZZ Top album Antenna ZZ Top album , the eleventh studio album by American blues rock band ZZ Top, released in 1994 Antenna film Antenna film , a satirical 1969 Dutch film directed by Adriaan Ditvoorst Antenna , an episode of the Adult Swim animated television series ... terrestrial television channel Antenna TV , a U.S. television channel established in 2011 ... radio station RDP Antena 3 , Portuguese public radio station See also Aerial disambiguation Antenna ... more details
In telecommunication s and radar engineering, antenna boresight is the axis of maximum antenna gain gain maximum radiated power of a Directional antenna directional Antenna radio antenna . For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial fed dish antenna s, the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna radiation pattern the main lobe is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antenna s can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions multiple boresights . ref http www.ccrs.nrcan.gc.ca glossary index e.php?id 3158 ref The term boresight came from high gain antenna s such as parabolic dishes, which produce narrow, pencil shaped beams which are difficult to aim accurately at a distant receiving antenna. These often are equipped with optical boresight firearm boresight s to assist in aiming. References reflist Category Antennas radio telecomm stub ... more details
In telecommunication s and antenna radio antenna design, an image antenna is an electrical mirror image of an antenna radio antenna element formed by the radio waves reflecting from a conductive surface called a ground plane , such as the surface of the earth. It is used as a geometrical technique in calculating the radiation pattern of the antenna. When a radio antenna is mounted above a conductive surface such as the ground electricity earth , the radio waves directed down toward the surface reflect off it. The radiation received at a distant point is the sum of two contributions the waves that travel directly from the antenna to the point, and the waves that reach the point after reflecting off the ground plane. Because of the reflection, these second waves appear to come from a second antenna behind the plane, just as a visible object in front of a flat mirror forms a virtual image that seems to lie behind the mirror. The radiation pattern of the antenna is exactly the same as it would be if the ground plane were replaced by a mirror image of the antenna, located an equal distance behind the plane. This second apparent source of radio waves is the image antenna. The image antenna ... from the real antenna, particularly in the vicinity of the antenna and along the ground. Each charge and current in the real antenna has its counterpart in the image, and may also be considered as a source of radiation . To form an image of the antenna above it, the ground plane need not be grounded to the Earth. Many antenna types, such as reflective array antenna s, use flat surfaces of metal or metal screen to reflect radio waves from the antenna elements, and these can be analyzed using image antennas. If there is more than one reflective surface in the antenna, as in a corner reflector antenna, each surface forms its own image of the antenna elements. In order to form an image ... waves used. FS1037C MS188 Category Radio frequency antenna types ... more details
Unreferenced auto yes date December 2009 Image Antenna feed1.JPG thumb Typical feed horn for a satellite communications dish antenna. In telecommunications and electronics , an antenna feed refers to the components of an Antenna radio antenna which feed the radio wave s to the rest of the antenna structure, or in receiving antennas collect the incoming radio waves, convert them to electric currents and transmit them to the receiver. Antennas typically consist of a feed and additional reflecting or directive structures such as a parabolic dish or parasitic element s whose function is to form the radio waves from the feed into a beam or other desired radiation pattern . In simple antennas the feed usually consists of the feed antenna driven element , the part of the antenna which actually converts the radio frequency currents to radio waves or vice versa, and the feed line transmission line , which connects the feed antenna with the receiver or transmitter. For example, in a rooftop Yagi Uda antenna Yagi television antenna , the feed consists of a dipole antenna dipole driven element, which converts the radio waves to an electric current, and a coaxial cable or twin lead transmission line which conducts the received signal from the antenna into the house to the television receiver . In more complex antenna systems the feed can be more complicated. The antenna feed is usually considered to be all the components between the beam shaping part of the antenna and the receiver s first amplifier called the RF front end , the Low noise block converter LNB or Low noise amplifier LNA . For a transmitting antenna, the feed consists of everything after the last High Power Amplifier power amplifier , and might include an antenna tuner unit and impedance matching sections at the antenna. In a radar or satellite communications antenna the feed might consist of a Horn antenna feed horn ... , etc. DEFAULTSORT Antenna Feed Category Antennas Feed Wireless stub ... more details
Unreferenced date October 2008 A reference antenna is an Antenna radio antenna with known performance. It is normally used to calibrate other systems. Reference antennas are built with particular care taken to make them simple, robust and repeatable. In a common usage scenario a reference antenna would be used as a transfer standard. First the reference antenna s performance is measured using high accuracy measurement facility. This test may be done using an Electromagnetic Anechoic chamber or another type of Antenna Test Range see Antenna Measurements . The antenna is then measured using a second antenna test facility. The results from the two are compared, the comparison can reveal the accuracy of the second test facility. It can also be used to calibrate the second facility. Sometimes rather than measure the performance of the reference antenna theoretical methods are used. The antenna may be simulated using electromagnetic simulation, or its properties derived from formulae based on electromagnetic theory. These methods are only useful if the materials and dimensions of the antenna can be characterised very well, and the mathematics of the simulation or formulae used is known to be accurate. Normally the parameter of interest is antenna gain . In this case the reference antenna is built to have a high degree of repeatability in its radiation pattern and boresight gain. A common practice is to measure the boresight gain of a reference antenna across its operational frequency band. Other parameters are sometimes of interest though, such as antenna Electrical efficiency efficiency . Common reference antennas are Horn antenna Horns , Dipole antenna dipoles , Monopole antenna monopoles and Biconical antenna Biconicals . These types are chosen because they are mechanically simple and quite electrically simple. Mechanical simplicity makes building repeatable antennas easier .... Antenna Types Category Radio frequency antenna types Telecomm stub ... more details
Image SatelliteAntenna 137MHz.jpg thumb right A turnstile antenna for Low Earth Orbit LEO weather satellites . A turnstile antenna is a set of two dipole antenna s aligned at right angles to each other and fed 90 degrees out of phase. The name reflects that the antenna looks like a turnstile when mounted horizontally. When mounted horizontally the antenna is nearly omnidirectional on the horizontal plane. When mounted vertically the antenna is directional to a right angle to its plane and is circularly polarized . The turnstile antenna is often used for communication satellite s because, being circularly polarized, the polarization of the signal doesn t rotate when the satellite rotates. The principles of the turnstile antenna are also applicable to Yagi antenna Yagi and Log periodic antenna s. External links http www.mikestechblog.com joomla ham radio ham radio antennas category 65 2 meter turnstile antenna for amateur satellite communications.html Turnstile Construction plans for satellite communication http www.west.net jay turnstile.html Construction plans http www.digitalham.co.uk weather equipment turnstile antenna Turnstile design for APT weather satellite reception Antenna Types radio comm stub mast stub Category Radio frequency antenna types de Kreuzdipol sv V ndkorsantenn it Antenna turnstile ... more details
Unreferenced date December 2009 Image LPDA large.jpg thumb right Log periodic dipole array A directional antenna or beam antenna is an antenna electronics antenna which radiates greater power in one or more directions allowing for increased performance on transmit and receive and reduced Interference communication interference from unwanted sources. Directional antennas like Yagi Uda antenna s provide increased performance over dipole antenna s when a greater concentration of radiation in a certain direction is desired. All practical antennas are at least somewhat directional, although usually only the direction in the plane parallel to the earth is considered, and practical antennas can easily be omnidirectional antenna omnidirectional in one plane. The most common types are the Yagi Uda antenna , the log periodic antenna , and the corner reflector , which are frequently combined and commercially sold as residential TV antenna s. Cellular repeater s often make use of external directional antennas to give a far greater signal than can be obtained on a standard cell phone . Satellite Television receivers usually use parabolic antenna s. For long and medium wavelength frequencies , tower array s are used in most cases as directional antennas. See also Amateur radio direction finding Cantenna Cardioid Cassegrain antenna Cassegrain reflector Antenna gain High gain antenna Loop antenna Omnidirectional antenna Parabolic antenna Radio direction finder Radio propagation model , Antenna subsection References Reflist Antenna Types DEFAULTSORT Directional Antenna Category Radio frequency antenna types de Richtantenne es Antena direccional lt Kryptin antena pl Antena kierunkowa ... more details
Refimprove date March 2008 In telecommunication , a periscope antenna is an antenna electronics antenna configuration in which the transmitting antenna is oriented to produce a vertical radiation pattern , and a flat or off axis parabolic reflector , mounted above the transmitting antenna, is used to direct the wikt beam beam in a horizontal Course navigation path toward the receiving antenna. A periscope antenna facilitates increased terrain clearance without long transmission line s, while permitting the active equipment to be located at or near ground level for ease of repair and maintenance maintenance . Sources FS1037C MS188 Category Radio frequency antenna types radio comm stub ... more details
Image Indoor Antenna Rabbit Ears DSCN2540a.jpg thumb 180px right TV set top indoor antenna Rabbit Ears for VHF and UHF reception. see also Television antenna An Indoor antenna is a type of radio antenna radio or TV antenna placed indoors, as opposed to being mounted on the roof. Indoor antennas are usually a simple and cheap solution that may work well when the receiver is relatively near to the broadcasting transmitter and the building walls do not shield the radio waves too much. Being close to other electric or electronic equipment in the building, an indoor antenna is prone to picking up more electrical noise that may interfere with a clear analog reception. Used for digital broadcast, the noise is less of a factor, which recently makes this type of antenna a more popular solution. See also Television antenna External links http www.avsforum.com avs vb showthread.php?t 1037779 AVSforum EV s Best Top Rated HDTV Indoor Antenna Review Test Round Up Guide Category Antennas radio Category Radio electronics fr antenne d int rieur ... more details
Unreferenced date December 2009 File Vu2gmn antenna.jpg thumb right 300px An antenna rotator unit is visible in the middle of the mast. An Antenna radio antenna rotator is a device which is used to change the orientation of a directional antenna . Most antenna rotators have two parts, the rotator unit and the controller. The controller is normally placed near the equipment which the antenna is connected to, while the rotator is mounted on the antenna mast directly below the antenna. Rotators are commonly used in amateur radio and military communications installations. They are also used with TV and FM broadcasting FM antennas, where stations are available from multiple directions, as the cost of a rotator is significantly less than that of installing a second antenna to receive stations from multiple directions. Rotators are manufactured for different sizes of antennas and installations. For example, a consumer TV antenna rotator has enough power to turn a TV FM or small Ham antenna. These units typically cost around US 70. Heavy duty Ham rotators are designed to turn extremely large, heavy, high frequency shortwave beam antennas, but cost hundreds and possibly thousands of dollars. DEFAULTSORT Antenna Rotator Category Antennas Mast stub ... more details
refimprove date November 2011 File Biconical antenna.png thumb Biconical antenna In radio systems, a biconical antenna is a broad Bandwidth signal processing bandwidth antenna made of two roughly conical conductive objects, nearly touching at their points. ref name ZZ07 Zhuohui Zhang, Analysis and design of a broadband antenna for software defined radio , ProQuest, 2007 ISBN 0 549 46376 3, page 6 ref Biconical antennas are broadband dipole antennas, typically exhibiting a bandwidth of 3 octave disambiguation octaves or more. File Schwarzbeck RE 1790.jpg 175px right thumb Omnidirectional biconical antenna The conical conductors need not be solid cones nor infinitely long. A simple conical monopole antenna is a wire approximation of the solid biconical antenna and has increased bandwidth over a simple monopole . A common variant is the Discone antenna , where one of the cones is replaced with a flat disk. A bowtie antenna is a wire approximation in two dimensions of a biconic dipole antenna used, for example, for Ultra high frequency UHF television reception . The biconical antenna has ... infinite antenna resembles that of a transmission line . For an infinite antenna, the characteristic ... dipole arrays, Yagi Uda antenna s, and reverberation chambers have shown to achieve much higher field strengths for the power input than a simple biconical antenna in an anechoic chamber. File 9112.jpg ... 1040 2804 800px ultra low cost dvb t schmetterlingsantenne.jpg thumb DIY DVB T butterfly antenna, applicable in the so called core area See also Discone antennaAntenna electronics Antenna Radio Television ... links http njivy.org node tim kyle discone antenna for 802 11b wi fi Tim Kyle s Discone Antenna Link Dead http www.northcountryradio.com Articles discone.htm UHF Discone Antenna http www.qsl.net kb7qhc antenna Discone discone.htm The Discone Antenna http www.youtube.com watch?v xhW4QQruBTo Home made video Antenna Types Category Radio frequency antenna types engineering stub radio comm stub de ... more details
In telecommunications , the antenna factor is defined as the ratio of the incident electromagnetic field strength to the voltage V units V or V on the line connection of an antenna radio antenna . For an electric field antenna, the field strength is in units of V m or V m and the resulting antenna factor AF is in units of 1 m math AF frac EV math If all quantities are expressed logarithmically in decibel s instead of SI unit s, the above equation becomes math AF mathrm dBm 1 E mathrm mathrm dBV m V mathrm dBV E mathrm mathrm dB mu mathrm V m V mathrm dB mu mathrm V math For a magnetic field antenna, the field strength is in units of A m and the resulting antenna factor is in units of A Vm . For the relationship between the electric and magnetic fields, see the impedance of free space . In a 50 system, the antenna factor is related to the antenna gain G and the wavelength via math AF frac 9.73 lambda sqrt G math The variable G means antenna gain dimensionless and it can be written in terms of effective aperture A to obtain the final expression considering the impedance of free space 376.7 and the load as 50 . The antenna effective aperture can be written as A sup 2 sup G 4 . References http www.tdkrfsolutions.com DataPDFs antenna paper part3.pdf Interpreting Antenna Performance Parameters for EMC Applications http www.djmelectronics.com articles emc antenna parameters p3.html Interpreting Antenna Performance Parameters for EMC Applications Dead link date July 2010 An excellent page with summaries of all the relevant equations http www.antenna theory.com definitions antennafactor.php Antenna Theory Category Antennas radio ... more details
File Aerial antenna.JPG thumb right 250px A multiband US television reception antennaAntenna array may refer to Antenna array electromagnetic a group of isotropic radiators such that the currents running through them are of different amplitudes and phases Interferometry Interferometric array of radio telescopes used in radio astronomy Phased array , also known as a smart antenna , an electronically steerable directional antenna typically used in Radar and in wireless communication systems, in view to achieve beamforming , multiple input and multiple output MIMO communication or space time coding Directional array refers to multiple antennas arranged such that the superposition of the electromagnetic waves produce a predictable electromagnetic field. Direction finding Watson Watt .2F Adcock antenna array Watson Watt Adcock antenna array the Watson Watt technique uses two Adcock antenna pairs to perform an amplitude comparison on the incoming signal. References reflist disambig ... more details
Multiple issues orphan January 2010 refimprove December 2010 File Arrt antenna.jpg thumb right MW Antenna Vidin Bulgaria ARRT Typ An ARRT Antenna Cyrillic is the designation of a common type used on many AM radio AM broadcasting sites in former Soviet Union , Bulgaria and Albania . It consists of a cage antenna which is mounted around the lower parts of a mast radiator insulated against ground and insulated from the mast. The mast and the cage antenna are fed separately. The ARRT antenna allows a radiation pattern with less skywave radio propagation and is easier realizeable than a mast divided by insulator s. A variant of ARRT antennas uses a grounded mast and a cage antenna reaching from the bottom to the top of the mast. Such antennas are used e.g. at the mediumwave masts of Bolshakovo transmitter. See also Zarya antenna Zarya External links http www.radioscanner.ru forum topic26813 2.html Pictures of a broadcasting station in Russia with ARRT Antenna http pritjazanie.pp.ua korotkovolnovaja svjaz 4.html Theory of ARRT Category Communications in Russia de ARRT uk ... more details
Expand Dutch date May 2009 Antenna film Infobox Film name Antenna film image image size caption director Adriaan Ditvoorst producer writer narrator starring music cinematography editing distributor released 1969 runtime country film Netherlands language Dutch budget Antenna film is a 1969 in film 1969 cinema of the Netherlands Dutch film directed by Adriaan Ditvoorst . Cast Empty section date July 2010 External links imdb title id 0315199 title Antenna CinemaoftheNetherlands DEFAULTSORT Antenna Film Category Dutch films Category 1969 films Category Black and white films Category Films directed by Adriaan Ditvoorst Category Films shot in the Netherlands nl Antenna film ... more details
In radio communication and avionics a conformal antenna or conformal array is a flat radio antenna radio antenna which is designed to conform or follow some prescribed shape, ref name Josefsson cite book last Josefsson, Patrik Persson first Lars Josefsson, Patrik Persson authorlink coauthors Patrik Persson title Conformal array antenna theory and design publisher John Wiley and Sons year 2006 location USA pages 1 9 url http books.google.com books?id AVl9d50C W0C&printsec frontcover v onepage&q&f false doi id isbn 0 471 46584 4 ref a flat curving antenna which is mounted on or embedded in a curved surface. Conformal antennas were developed in the 1980s as avionics antennas integrated into the curving skin of military aircraft to reduce aerodynamic drag , replacing conventional antenna designs ... antennas, to save space and also to make the antenna less visually intrusive by integrating it into existing objects. How it works Conformal antennas are a form of phased array antenna. They are composed of an array of many identical small flat antenna elements, such as dipole antenna dipole , horn antenna horn , or patch antenna s, covering the surface. Each antenna is driven by a phase shifter device ... in front of the antenna by the process of interference wave propagation interference , forming a strong ... antenna the weak individual radio signals received by each antenna element are combined in the correct phase to enhance signals coming from a particular direction, so the antenna can be made sensitive ... phased array the individual antenna elements are mounted on a flat surface. In a conformal antenna, they are mounted on a curved surface, and the phase shifters also compensate for the different ... antennas on the curved surface. Because the individual antenna elements must be small .... References Reflist Category Antennas radio Category Radio frequency antenna types Category Aerospace engineering Antenna Types ... more details
A coaxial antenna often known as a coaxial dipole is a particular form of a half wave dipole antenna , most often employed as a vertically Polarization waves polarized omnidirectional antenna . History Arnold B. Bailey was granted the US patent 2,184,729 Antenna System on December 26, 1939 after filing in 1937 for a vertical antenna providing coaxial element sleeve structures. Bonnie Crystal was granted the http www.google.com patents about?id xkp AAAAEBAJ&dq 7,151,497 US patent 7,151,497 Coaxial Antenna System on December 19, 2006 after filing in 2003 for new types of coaxial antennas with reduced size providing efficient broadband, wideband and controlled bandwidths, using radiation by the outside of the coaxial elements. Configuration In the most basic form, a quarter wavelength section of coaxial cable is prepared such that the inner and outer conductors are separate but still attached to the remaining cable. The outer sheath conductor is connected to a quarter wavelength conducting sleeve into which the cable is inserted, and the inner conductor protrudes vertically above the sleeve for a quarter wavelength. Also, additional quarter wavelength sections may be connected to outer conductor to form a better ground plane. Bazooka Dipole coaxial antenna Dipole antennas constructed using coaxial cables with shorted ends are often given the name Bazooka dipoles. See also Amateur radio Antennas Coaxial cable Dipole antenna External links http www.aktuellum.com circuits antenna patent patents 2184729.pdf Bailey s 1939 patent PDF http searchmobilecomputing.techtarget.com sDefinition 0,,sid40 gci214302,00.html what is Coaxial antenna a definition from Whatis.com http www.google.com patents?id xkp AAAAEBAJ&dq coaxial antenna system Coaxial Antenna System patent number 7151497 Antenna Types Category Radio frequency antenna types Electron stub ... more details
Image L over2 rad pat per.jpg thumb The radiation pattern of a simple omnidirectional antenna, a vertical half wave dipole antenna . In this graph the antenna is at the center of the donut . Radial distance ... in horizontal directions, dropping to zero directly above and below the antenna. In radio communication , an omnidirectional antenna is an antenna electronics antenna which radiates radio wave power ... or below the plane, dropping to zero on the antenna s axis. This radiation pattern is often described as doughnut shaped . Note that this is different from an isotropic radiator isotropic antenna ... antennas are the whip antenna , Rubber Ducky antenna Rubber Ducky , Monopole antenna ground plane antenna , vertically oriented dipole antenna , discone antenna , mast radiator , horizontal loop antenna sometimes known colloquially as a circular aerial because of the shape , and the halo antenna . Higher gain omnidirectional antennas can also be built. Higher gain in this case means that the antenna ... the current in each dipole is in phase. ref cite book editor Johnson, R, Jasik, H title Antenna ... or COCO antenna uses transposed coaxial sections to produce in phase half wavelength radiators ... antennas are the coaxial collinear COCO antenna ref cite journal doi 10.1109 8.18724 author Judasz, T., Balsley, B. title Improved Theoretical and Experimental Models for the Coaxial Colinear Antenna ... 1989 ref and Omnidirectional Microstrip antenna Microstrip Antenna OMA . ref cite journal doi 10.1002 mop.21187 author Bancroft R title Design Parameters of an Omnidirectional Planar Microstrip Antenna .... ref cite web author Yanaga Kurashima Arita Kobayashi title A Planar UWB Monopole Antenna Formed on a Printed ... VHF UHF biconical antenna 170 1100 MHz with omni directional H plane pattern Image Vpol dual band blade antenna blade L1 3D.jpg thumb Radiation pattern of a 3 2 monopole antenna. Although the radiation of an omnidirectional antenna is symmetrical in azmuthal directions, it may vary in a complicated ... more details
Refimprove date December 2006 Image Monopole.jpg thumb right 250px Mast radiator monopole antenna used for broadcasting. AM radio station WARE, Warren, Massachusetts, USA. A monopole antenna is a class of radio antenna consisting of a straight rod shaped conductor, often mounted perpendicularly over ... end of the monopole and the ground plane. One side of the antenna feedline is attached to the lower .... This contrasts with a dipole antenna which consists of two identical rod conductors, with the signal from the transmitter applied between the two halves of the antenna. Common types of monopole antenna are the whip antenna whip , Rubber Ducky antenna rubber ducky , helical antenna helical , Random wire antenna random wire , mast radiator , and ground plane antennas. Radiation pattern Like a dipole antenna , a monopole has an Omnidirectional antenna omnidirectional radiation pattern . That is it radiates equal power in all azimuthal directions perpendicular to the antenna, but the radiated power varies with elevation angle, with the radiation dropping off to zero at the zenith, on the antenna ... as being formed by replacing one half of a vertical dipole antenna with a ground plane at right ... the ground plane will seem to come from an image antenna forming the missing half of the dipole, which ... maximum radiation in the horizontal direction, perpendicular to the antenna. Because it radiates only into the space above the ground plane, or half the space of a dipole antenna, a monopole antenna will have a antenna gain gain of twice 3 decibel dBi over the gain of a similar dipole antenna, and a radiation resistance half that of a dipole. Thus a Quarter wave antenna quarter wave monopole ... earth in this case the antenna is mounted on the ground and one side of the feedline is connected to an earth ground electricity ground at the base of the antenna. This design is used for the mast ... frequency antennas such as the T antenna and umbrella antenna . At Very high frequency VHF and Ultrahigh ... more details
Image SWR analyzer measuring a dummy load.jpg 250px thumb An antenna analyzer measuring SWR and complex impedance of a dummy load. MFJ Enterprises Inc. MFJ 269. An antenna analyzer also known as a noise bridge , RX bridge , SWR analyzer , or RF analyzer is a device used for measuring the efficiency of antenna radio antenna systems in radio electronics applications. Theory of operation The antenna analyzer is essentially a bridge where two legs are frequency dependent complex number complex valued Electrical impedance impedance s by impedance matching these legs. When the two impedances are the same the bridge will be balanced. Using this circuit it is possible to either measure the impedance of the antenna connected between ANT and GND, or it is possible to adjust an antenna until it has the same impedance as the network on the left hand side. The bridge can be driven either with white noise or a simple carrier connected to drive . In the case of white noise the amplitude of the exciting signal can be very low and a radio receiver used as the detector. In the case where a simple carrier ... antenna bridge, the trimmer electronics trimmer capacitor C is adjusted to make the bridge balance ... if an Antenna radio aerial is either a resistive or inductive load. Unlike an SWR meter which measures the standing wave ratio in the cable feeding the antenna, a complex impedance antenna analyzer requires little or no transmitted power applied to the antenna. The SWR meter works by measuring the Reflection electrical reflected wave from the antenna back to the transmitter , which is minimal when the antenna is balanced. A badly tuned antenna can produce enough reflected power to damage the transmitter ... Many amateur radio operators use antenna analyzers to optimize an existing antenna or troubleshoot antenna related problems such as diagnosing a break in coax cable and finding faulty antenna components ... Antenna analyzer DEFAULTSORT Antenna Analyzer Category Electrical circuits Category Electronic test ... more details
unreferenced date April 2011 In antenna theory, radiation efficiency , which is often abbreviated to just efficiency is a figure of merit for an Antenna radio antenna . It is a measure of the electrical losses that occur in the antenna. Radiation efficiency is defined by IEEE Std 145 1983 Definitions of Terms for Antennas as The ratio of the total power radiated by an antenna to the net power accepted by the antenna from the connected transmitter. It is sometimes expressed as a percentage. It will be frequency dependent. The antenna gain gain of an antenna is the directivity multiplied by the radiation efficiency. The IEEE standard defines several antenna parameters which include the word efficiency, such as antenna efficiency of an aperture type antenna. antenna illumination efficiency. polarization efficiency polarization mismatch factor. solid beam efficiency. All of these have different definitions and should not be confused with radiation efficiency, which is by far the most commonly used term. Components of radiation efficiency Antenna efficiency depends on three kinds of loss dubious date February 2012 coil losses math R c math , ground losses math R g math , and other losses math R o math including ohmic and capacitive losses. The antenna s total resistance math R t math is the sum ... R other math Antenna efficiency is the ratio between its radiation resistance and its total resistance math E radiation frac R radiation R total math Ground loss For monopole antenna monopole and other ground plane antennas, ground loss occurs due to ohmic electrical resistance resistance in the antenna ... is the loss due to ohmic electrical resistance resistance in the conductors of the antenna s driven ... the antenna and any nearby conductive structures. Stray capacitance causes a loss because capacitor ... forms between any two conductors separated by an insulator in this case, one conductor is the antenna ... is very small typically picofarad s , it impacts antenna performance in direct proportion to frequency ... more details
File Slot antenna section3.jpg thumb right 250px Cross section of a slotted waveguide antenna from a marine radar set. A slot antenna consists of a metal surface, usually a flat plate, with a hole or slot cut out. When the plate is driven element driven as an antenna radio antenna by a driving frequency, the slot radiates electromagnetic wave s in similar way to a dipole antenna . The shape and size of the slot, as well as the driving frequency, determine the radiation pattern radiation distribution pattern . Often the radio waves are provided by a waveguide , and the antenna consists of slots in the waveguide. Slot antennas are often used at Ultrahigh frequency UHF and microwave frequencies instead of line antennas when greater control of the radiation pattern is required. Slot antennas are widely used in radar antennas, for the sector antenna s used for cell site cell phone base stations , and are often found in standard desktop microwave sources used for research purposes. A slot antenna s main advantages are its size, design simplicity, robustness, and convenient adaptation to mass production using PC board technology. The slot antenna was invented in 1938 by Alan Blumlein , while working for EMI . He invented it in order to produce a practical type of antenna for VHF television broadcasting that would have horizontal polarization, an omni directional horizontal radiation pattern and a narrow vertical radiation pattern. ref citation first Alan last Blumlein title Improvements in or relating to high frequency electrical conductors or radiators work British patent no. 515684 date 1938 03 07 ref ref cite book title The life and times of A D Blumlein first Russell last Burns publisher Institution of Engineering and Technology year 2000 ISBN 0 85296 773 X ref References reflist See also Slotted waveguide External links http www.antenna theory.com antennas aperture slot.php Slot Antennas www.antenna theory.com Antenna Types Category Radio frequency antenna types tech stub ... more details
Image Car radio antenna extended portrait.jpeg thumb Whip antenna on car A whip antenna is an antenna electronics antenna consisting of a single straight flexible wire or rod, often mounted above some ... tubes, so they can be retracted when not in use. They are the most common type of monopole antenna ... pattern The whip antenna can be considered half of a dipole antenna , and like a vertical dipole has an Omnidirectional antenna omnidirectional radiation pattern , radiating equal radio power in all azimuthal directions perpendicular to the antenna s axis , with the radiated power falling off with elevation angle to zero on the antenna s axis. Vertical whip antennas are widely used for Non directional antenna nondirectional radio communication on the surface of the Earth, where the direction to the transmitter ... the length of the whip antenna is determined by the wavelength of the radio waves used. The most common length is one quarter of the wavelength, called a Quarter wave antenna quarter wave whip although this type of antenna is often shortened by the use of a loading coil see Electrically short whips ... waves in the FM radio band, which are 2.78 to 3.41 meters long. Half wave antenna Half wave whip antennas ... wave whip has a Antenna gain gain twice 3 dB greater than that of a Half wave antenna half wave ..., and the ground side of the antenna s feed line is just connected to the ground on the device .... Since these are no larger than the size of the antenna itself, the combination of whip and radio often functions more as an asymmetrical dipole antenna than as a monopole. In stationary whip antennas ... the base of the whip is often used. This type of antenna is called a ground plane antenna . ref Straw, R. D. The ARRL Antenna Book. Newington, CT ARRL, 2005. Print. ref Electrically short whips Image .... This is a variation called a Rubber Ducky antenna on a handheld Ultrahigh frequency UHF Citizen s band CB transceiver. To reduce the length of a whip antenna to make it less cumbersome, an inductor loading ... more details
Unreferenced stub auto yes date December 2009 In a phased array or slotted waveguide antenna, squint refers to the angle that the transmission telecommunications transmission is offset from the Surface normal normal of the plane mathematics plane of the antenna. Image Squint Angle.png thumb right An example of squint caused by two differing frequencies This deflection can be caused by Signal Frequency As the frequency changes the relation of the signal to the phased array or slotted waveguide slots changes. Design In some cases the antenna may be designed to create a squint. For example, an antenna which is used to communicate with a satellite but must remain in a vertical configuration. Squint is also required in conical scanning . DEFAULTSORT Squint Antenna Category Antennas radio Tech stub ... more details
merge Patch antenna discuss Talk Microstrip antenna Merge.3F date January 2012 Unsourced image removed Image conformal patches.jpg thumb 250px Conformal Patch Antennas Image Antenna flat panel.png 400px thumb Image x band patch.jpg thumb 250px Xband Patch antenna with dime for size comparison In telecommunication , there are several types of microstrip Antenna radio antennas also known as printed antennas the most common of which is the microstrip patch antenna or patch antenna . Patch antenna A patch antenna is a narrowband, wide Light beam beam antenna fabricated by etching the antenna element ... plane . Common microstrip antenna shapes are square, rectangular, circular and elliptical, but any ... and higher frequencies because the size of the antenna is directly tied to the wavelength at the resonance resonant frequency . A single patch antenna provides a maximum directive gain of around 6 9 ... in a low profile antenna is one reason that patch arrays are common on airplanes and in other military .... ref Bancroft, R. Microstrip and Printed Antenna Design Noble Publishing 2004, chapter 2 3 ... have varied requirements. Rectangular patch The most commonly employed microstrip antenna is a rectangular patch. The rectangular patch antenna is approximately a one half wavelength long section of rectangular microstrip transmission line. When air is the antenna substrate, the length of the rectangular microstrip antenna is approximately one half of a free space wavelength . As the antenna is loaded with a dielectric as its substrate, the length of the antenna decreases as the relative dielectric constant of the substrate increases. The resonant length of the antenna is slightly shorter because of the extended electric fringing fields which increase the electrical length of the antenna slightly. An early model of the microstrip antenna is a section of microstrip transmission line with equivalent ... of a microstrip antenna affects both its radiation pattern and impedance bandwidth. As the dielectric ... more details
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