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Topic: Horn Antenna

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	Horn Antenna - Wikipedia, the free encyclopedia
		The antenna is 50 feet (15 m) in length with a radiating aperture of 20 by 20 feet (6 by 6 m) and is made of aluminum.
		The antenna's elevation wheel is 30 feet (10 m) in diameter and supports the weight of the structure by means of rollers mounted on a base frame.
		To permit the antenna beam to be directed to any part of the sky, the antenna is mounted with the axis of the horn horizontal.
	en.wikipedia.org /wiki/Horn_Antenna (835 words)

	horn antenna - a Whatis.com definition (Site not responding. Last check: 2007-10-08)
		A horn antenna is used for the transmission and reception of microwave signals.
		Horn antennas are commonly used as the active element in a dish antenna.
		Horn antennas are used all by themselves in short-range radar systems, particularly those used by law-enforcement personnel to measure the speeds of approaching or retreating vehicles.
	whatis.techtarget.com /definition/0,289893,sid9_gci214327,00.html (280 words)

	Feed horn - Wikipedia, the free encyclopedia
		In satellite dish and antenna design parlance, a feedhorn (or feed horn) is a horn antenna used to convey radio waves between the transceiver (transmitter and/or receiver) and the reflector.
		The feedhorn also selects the polarity of the waves to be received, which helps to attenuate unwanted signals from adjacent channels and transponders, and from other communications satellites at nearby orbital positions.
		When used with a parabolic reflector or lens antenna, the phase center of the horn is usually placed at the focal point of the reflector, with the 3dB points of the horn's radiation pattern set to be at the edge of the reflector.
	en.wikipedia.org /wiki/Feed_horn (227 words)

	BACKGROUND INFORMATION
		In particular we shall define the electromagnetic horn antenna, it is a subclass of aperture antennas.
		In addition the horn antenna is often used as a source, or "feed", to distribute electromagnetic energy over the surface of a parabolic reflector or lens.
		The purpose of extending the ridges into the horn is, again, to lower the TE cutoff frequency thus improving the operating bandwidth of the horn.
	www.ecs.umass.edu /mie/labs/mda/fea/fealib/moser/bground.htm (2318 words)

	National Park Service: Astronomy and Astrophysics (Horn Antenna)
		The antenna is 50 feet in length with a radiating aperture of 20 x 20 feet and is made of aluminum.
		The antenna's elevation wheel is 30 feet in diameter and supports the weight of the structure by means of rollers mounted on a base frame.
		The Horn Antenna, at the Bell Telephone Laboratories in Holmdel, New Jersey, is significant because of its association with the research work of two radio astronomers, Dr. Arno A. Penzias and Dr. Robert A. Wilson.
	www.cr.nps.gov /history/online_books/butowsky5/astro4k.htm (1555 words)

	Multifrequency broadband polarized horn antenna - Patent 4258366 (Site not responding. Last check: 2007-10-08)
		A multifrequency, broadband, dual-polarized corrugated conical horn antenna is simultaneously fed a multiplicity of signals, two for each of five frequencies, with each of a pair of signals fed in each of two orthogonal planes for excitation of a desired spherical hybrid mode (HE.sub.11).
		This antenna system is insensitive to frequency and polarization changes, and would therefore be suitable for multifrequency dual-polarized scanning purposes, but the problem is simultaneously feeding the corrugated conical horn with more than one frequency when the frequencies are spaced over one or more octaves.
		The higher frequency is fed at the vertex of the horn in the usual manner, and the lower frequencies are fed into the horn where the cross-sectional dimensions are greater.
	www.freepatentsonline.com /4258366.html (2992 words)

	A Horn Antenna for 2 (Site not responding. Last check: 2007-10-08)
		This Antenna is not really practical for AO-40 reception, but horn antennas have a number of qualities useful in microwave antenna testing and noise figure measurements.
		Antennas under test can be directly compared with the horn and their gain and polarity can measured relative to the performance of the standard horn.
		Another application of a horn antenna is the measurement of system noise figure by using a comparison of cold sky and 'hot' ground.
	www.g0mrf.freeserve.co.uk /horn.htm (302 words)

	[No title]
		A pyramidal horn antenna is flared in both directions, in the electrical field (E-field) and in the magnetic (H-field) to accomplish this.
		The theory used behind the electrical field for the horn antenna is the same as that of the TE mode waveguide.
		The horn antenna had to be flared from a standard waveguide to fit the side walls of the test fixture when opened.
	www.ee.unb.ca /thesis98/ee4000ag/page1.htm (1826 words)

	[No title]
		The gain horn antenna temperature may be easier to = measure than that of the large antenna, since a load covering the horn = is quite feasible (note that in their original experiment, Gibson and = Welch actually used the waveguide switch also to calibrate the antenna = temperature scale of the large antenna).
		In a proper = geometric setup (horn surrounded by a number of antennas), it could = easily be divided by 3 to 6 without resorting to baselines affected by = significant decorrelation.
		The antenna cost would be minimal (200-300 k$ perhaps): = since the mount of one of the prototypes could be re-used for this = purpose, only refurbishing of the cabin being required.
	www.cv.nrao.edu /~awootten/mmaimcal/sgcalproposal.txt (1162 words)

	The SETI League, Inc.: Waveguide Horn Antenna Photos
		He based his 1951 antenna design on the earlier work of University of California professor Samuel Silver at the MIT Radiation Laboratory, with its physical dimensions constrained by the size of the parapet in Harvard's Lyman laboratory where his receiver apparatus was installed.
		The assembly is inserted on the centerline of the e-field horn face, 3 inches from the apex of the truncated pyramid.
		However, the horn's excellent broadband impedance match, inherent lack of overspill, and low sidelobes mean its ground noise pickup will be significantly less than that of alternative antennas, providing a greater signal to noise ratio than one would expect from gain figures alone.
	www.setileague.org /photos/wghorn.htm (908 words)

	Doppler radar mounting structure for motor vehicles - Patent 4346774 (Site not responding. Last check: 2007-10-08)
		to the road surface 4, and therefore it is necessary to mount the horn antenna 1 on the casing 2 at an angle, thus complicating the structure of the casing.
		In the case of using a microwave circuit antenna such as a horn antenna in which the electromagnetic wave beam coincides with the axial direction of the antenna, the antenna-mounting plane forms an angle to the road surface.
		The opening of the horn antenna 1 is configured to form an angle of 45 degrees to one side of the casing facing the road surface when mounted on the vehicle.
	www.freepatentsonline.com /4346774.html (3530 words)

	Microwave Antennas and Parabolic Reflector Antennas (Site not responding. Last check: 2007-10-08)
		The slant length of a horn is longer than the axial length, and this gives rise to an aperture phase error which degrades the beam shape and reduces the gain.
		A small horn feeds the reflector, and the gain/beamwidth is determined by the width of the reflector aperture.
		A reflector antenna generally has lower sidelobes than a horn antenna, because the radiation distribution on the reflector is tapered towards the edge of the reflector, rather than being cut off abruptly.
	www.q-par.com /pages/Antenna_Concepts.htm (875 words)

	guide horn antenna
		As the use of broadband antennas extended, standards were changed to allow for the use of broadband antennas as long as the measurements performed with these antennas could be related to the half-wave dipole.
		Furthermore, a study of the fields in the antenna showed that the dielectric supports for these bars were having a detrimental effect on the main beam at the higher end of the range.
		The traditional design pattern behavior was not suitable for the antenna to be used as a source for reflectors or in anechoic chambers for antenna pattern measurement.
	rfdesign.com /mag/radio_new_broadband_emc/index.html (1755 words)

	dish antenna - a Whatis.com definition (Site not responding. Last check: 2007-10-08)
		A dish antenna consists of an active, or driven, element and a passive parabolic or spherical reflector.
		When the dipole or horn is properly positioned and aimed, incoming electromagnetic fields bounce off the reflector, and the energy converges on the driven element.
		If the horn or dipole is connected to a transmitter, the element emits electromagnetic waves that bounce off the reflector and propagate outward in a narrow beam.
	whatis.techtarget.com /gDefinition/0,294236,sid40_gci214328,00.html (250 words)

	FVTD — Ridged Horn (static version)
		Horns are widely used antennas since they have a simple construction, are easy to excite and have a large gain.
		They are employed for example as feed elements in satellite tracking systems or communication dishes and they serve as a standard antenna for calibration and gain measurements.
		Ridges on the side flares are introduced to extend the bandwidth, similar to the ridges in a waveguide that lower the cut-off frequency.
	www.ifh.ee.ethz.ch /~fvtd/fvtd_horn.html (450 words)

	CST World -
		This octagon antenna array consists of eight patch antennas, which are fed by a microstrip circuit connected to a coaxial line.
		A horn antenna with a dielectric cone, driven by a coaxial input.
		Antenna Arrays are a very powerfull way to set up a lot of antennas together on a small area.
	www.cst.de /Content/Articles/category1.aspx (709 words)

	[No title]
		For the ridged horn antenna it is found that the radiation pattern, contrary to common belief, does not maintain a single main lobe in the direction of the horn axis over the full frequency range.
		Although this type of horn is the preferred test antenna, which is in common use for over four decades, no explanation for this unwanted behavior was found in the open literature.
		For the ridged horn antenna it is found that the radiation pattern, contrary to common believe, does not maintain a single main lobe in the direction of the horn axis over the whole frequency range.
	www.ifh.ee.ethz.ch /Field/bib/2003.bib (2361 words)

	A.H. Systems - Horn Antennas
		The Standard Gain Horn Antennas are designed specifically for utilization in emissions and immunity testing over the frequency range of 1 to 40 GHz.
		Therefore, the antenna is considered to be a standard reference, similar to that of a resonant dipole below 1 GHz.
		Horizontal and vertical polarization is obtained by rotating the antenna on the tripod.
	www.ahsystems.com /catalog/horns.php (222 words)

	AT&T News Release, 1990-06-12, AT&T horn antenna named as national landmark (Site not responding. Last check: 2007-10-08)
		The antenna on Crawford Hill was used by Bell Labs scientists in 1965 to detect cosmic background radiation.
		The horn antenna is one of 16 astronomy sites recommended for designation as National Historic Landmarks out of 100 U.S. locations surveyed in 1989 by the park service.
		The horn antenna, at AT&T Bell Laboratories at Crawford Hill in Holmdel, New Jersey, is significant because of its association with the research work of two Bell Labs radio astronomers, Arno A. Penzias and Robert A. Wilson.
	www.att.com /press/0690/900612.bla.html (1188 words)

	Ground Penetrating Radar Antennas from GSSI
		GSSI has over 30 years experience in antenna design and manufacture, and has developed a wide range of antennas to meet the needs of a broad range of applications.
		The transmit antenna is triggered by pulses from the SIR System and radiates electromagnetic energy into the subsurface of media.
		Antenna design consists of interchangeable elements - by changing the length of the antenna, you can change the transmission frequency.
	www.geophysical.com /antennas.htm (654 words)

	Compact Antenna Replacements for C-Band Global Horns
		The launching section of the antenna is the same as that used for horn antennas and consists of a square septum polariser feed in the ground plane with two rectangular waveguide inputs, one for each direction of circular polarisation.
		The antenna was analysed using the principles of geometrical optics.
		The Von Trentini antenna has an open structure, and to obtain improved mechanical and electrical properties, it was decided to investigate a closed cavity design which offered a stiffer structure and a further reduction in aperture size.
	esapub.esrin.esa.it /pff/pffv5n2/crone.htm (799 words)

	Ewen-Purcell Horn
		This horn antenna, now displayed in front of the Jansky Lab at NRAO in Green Bank, WV, was used by Harold Ewen and Edward Purcell, then at the Lyman Laboratory of Harvard University, in the first detection of the 21 cm emission from neutral hydrogen in the Milky Way.
		Ewen proceeded to design the horn antenna and the mixer and receiver, consulting with experts in these fields, including Sam Silver on antenna design and Bob Pound on mixers.
		Ewen installed the completed horn antenna just outside a window on the fourth floor of the Lyman Lab at Harvard, with the waveguide leading in through the window to the receiver and recorder.
	www.gb.nrao.edu /~fghigo/fgdocs/HI21cm/ephorn.html (913 words)

	Remcom - XFDTD Examples (Site not responding. Last check: 2007-10-08)
		The pyramidal horn aperture dimensions are 18.46 cm by 14.55 cm with a path length of the horn apex of 29.75 cm.
		The horn is fed by a WR-90 waveguide with an input signal of 9.3 GHz.
		Similarly the second wedge for the other flare angle of the horn is drawn, then rotated to produce the outline of the horn shown in Figure 2.
	www.remcom.com /examples/xfdtdexampleDetailUpdated.php?exampleID=72&thisProduct=XFDTD60 (509 words)

	SETI Article: SETI Horn of Plenty
		He based his antenna design on the earlier work of University of California professor Samuel Silver at the MIT Radiation Laboratory [4], with its physical dimensions constrained by the size of the parapet in Harvard's Lyman laboratory where his receiver apparatus was installed.
		One of Tony's antennas, used for 2.4 GHz satellite reception, is shown in Figure 9, and was an inspiration for the SETI Horn of Plenty.
		Although this horn antenna suffers a three to four dB gain deficit when compared to the Ewen horn, today's receivers are at least ten dB more sensitive than the simple diode mixer design used by Ewen a half century ago.
	www.setileague.org /articles/horn.htm (1887 words)

	Price List
		The mounting cylinder is an antenna adapter used on the tripod Model TP1000A.
		The swivel head is an adapter assembly which allows 90° rotation of the microwave horn antenna for horizontal and vertical electric field testing.
		The antenna bracket is designed for each type waveguide depending on the type of horn antenna used.
	www.ar-amps.com /html/18200.asp?id=121 (149 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
		The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna.
		Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies.
		A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=644405 (220 words)

	CardboardHorn - SeattleWireless
		The waveguide, that feeds the horn, is a bottom of a Tetra Brik (see MicroTVAerial), the horn is made of cardboard coated with kitchen aluminium foil.
		Their big side is 25 cm (to match the box side), and the small sides match the milk box (6.5 cm and 9.5 cm).
		other (British) horn, he choose a cut-off frequency of 2 GHz (waveguide internal dimension is 76 x 38mm) to reject 1800 MHz cell phones.
	www.seattlewireless.net /index.cgi/CardboardHorn (302 words)

	Microwave Lens Horn
		Flann's lens horn antenna are gaining increasing acceptance as the most suitable antenna where size and performance are the drivers.
		A LHA has that enormous structural rigidity inherent in a cone, furthermore denting of this cone will have minimal effect on performance, except close to the neck, since it is not a critical reflective surface.
		LESS EXPENSIVE - Lens Horn Antennas are significantly less expensive than parabolas of similar performance and are ideally suited to both low and high volume applications.
	www.flann.com /Products_Home/Antennas/Lens_Horn/lens_horn.html (681 words)

	A Different Antenna
		In this case the antenna chosen was the discone antenna.
		The reflected energy from the double ridge horn antenna was sufficient to activate SWR (Standing Wave Ratio) shutdown circuitry in the TWT (Traveling Wave Tube) amplifiers thereby limiting the forward power available from the amp.
		A discone receiving antenna was purchased at a nationally known electronics store and tested for use as a receiving antenna (100 -1000 Mhz).
	www.ieee.org /organizations/pubs/newsletters/emcs/fall01/wills.html (1142 words)

	NSWC Dahlgren Division - 01Q3007 (Site not responding. Last check: 2007-10-08)
		The basis for sole source is the antenna being procured is identical to ones which NSWCDD has procured in the past for use in receiving surface to air missle telemetry on board U.S. Navy ships.
		The Navy requires this antenna to be 100% compatible and parts interchangeable with the existing antennas of this type.
		The transit case shall be capable of protecting the antenna and mast from damage in a commercial transportation environment.
	www.nswc.navy.mil /supply/solicita/03r1085/1085syn.htm (491 words)

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