2755:
2652:
548:
2720:
2640:
1326: – The maximum gain for any aperture antenna is only achieved when the intensity of the radiated beam is constant across the entire aperture area. However, the radiation pattern from the feed antenna usually tapers off toward the outer part of the dish, so the outer parts of the dish are "illuminated" with a lower intensity of radiation. Even if the feed provided constant illumination across the angle subtended by the dish, the outer parts of the dish are farther away from the feed antenna than the inner parts, so the intensity would drop off with distance from the center. Hence, the intensity of the beam radiated by a parabolic antenna is maximum at the center of the dish and falls off with distance from the axis, reducing the efficiency.
2771:
467:
2688:
491:
2676:
2735:
946:(XPD). In a transmitting antenna, XPD is the fraction of power from an antenna of one polarization radiated in the other polarization. For example, due to minor imperfections a dish with a vertically polarized feed antenna will radiate a small amount of its power in horizontal polarization; this fraction is the XPD. In a receiving antenna, the XPD is the ratio of signal power received of the opposite polarization to power received in the same antenna of the correct polarization, when the antenna is illuminated by two orthogonally polarized radio waves of equal power. If the antenna system has inadequate XPD,
181:
2700:
584:
560:
602:
20:
5691:
4605:
987:
1332: – In front-fed parabolic dishes where the feed antenna is located in front of the dish in the beam path (and in Cassegrain and Gregorian designs as well), the feed structure and its supports block some of the beam. In small dishes such as home satellite dishes, where the size of the feed structure is comparable with the size of the dish, this can seriously reduce the antenna gain. To prevent this problem these types of antennas often use an
298:
5701:
2664:
968:(though it is still very close), so the constant phase property is lost. This phase error, however, can be compensated for by slightly tweaking the shape of the primary mirror. The result is a higher gain, or gain/spillover ratio, at the cost of surfaces that are trickier to fabricate and test. Other dish illumination patterns can also be synthesized, such as patterns with high taper at the dish edge for ultra-low spillover
5680:
572:
503:
479:
5711:
4617:
3606:
1579:
536:
704:
1371:
875:
solid angle of the dish, dropping abruptly to zero at the edges. However, practical feed antennas have radiation patterns that drop off gradually at the edges, so the feed antenna is a compromise between acceptably low spillover and adequate illumination. For most front feed horns, optimum illumination is achieved when the power radiated by the feed horn is 10
683: – The reflector can be given a noncircular shape, or different curvatures in the horizontal and vertical directions, to alter the shape of the beam. This is often used in radar antennas. As a general principle, the wider the antenna is in a given transverse direction, the narrower the radiation pattern will be in that direction.
281:, which converts it into radio waves. The radio waves are emitted back toward the dish by the feed antenna and reflect off the dish into a parallel beam. In a receiving antenna the incoming radio waves bounce off the dish and are focused to a point at the feed antenna, which converts them into electric currents which travel through a
967:
may be used. This involves changing the shape of the sub-reflector to direct more signal power to outer areas of the dish, to map the known pattern of the feed into a uniform illumination of the primary, to maximize the gain. However, this results in a secondary that is no longer precisely hyperbolic
874:
or (in receiving antennas) increasing susceptibility to ground noise. However, maximum gain is only achieved when the dish is uniformly "illuminated" with a constant field strength to its edges. Therefore, the ideal radiation pattern of a feed antenna would be a constant field strength throughout the
835:
2885:
during World War II provided a great impetus to parabolic antenna research. This led to the evolution of shaped-beam antennas, in which the curve of the reflector is different in the vertical and horizontal directions, tailored to produce a beam with a particular shape. After the war, very large
321:
The reflector can be constructed from sheet metal, a metal screen, or a wire grill, and can be either a circular dish or various other shapes to create different beam shapes. A metal screen reflects radio waves as effectively as a solid metal surface if its holes are smaller than one-tenth of a
671: – Modern reflector antennas can be designed to produce a beam or beams of a particular shape, rather than just the narrow "pencil" or "fan" beams of the simple dish and cylindrical antennas mentioned above. Two techniques are used, often in combination, to control the shape of the beam:
2770:
1381:
is only a few degrees wide. The sidelobes are all at least 20 dB below (1/100 the power density of) the main lobe, and most are 30 dB below (if this pattern was drawn with linear power levels instead of logarithmic dB levels, all lobes other than the main lobe would be much too small to
451:). All that is necessary to change the frequency of operation is to replace the feed antenna with one that operates at the desired frequency. Some parabolic antennas transmit or receive at multiple frequencies by having several feed antennas mounted at the focal point, close together.
654:
located along the focal line. Cylindrical parabolic antennas radiate a fan-shaped beam, narrow in the curved dimension, and wide in the uncurved dimension. The curved ends of the reflector are sometimes capped by flat plates, to prevent radiation out the ends, and this is called a
779: – The reflector is an asymmetrical segment of a paraboloid, so the focus, and the feed antenna, are located to one side of the dish. The purpose of this design is to move the feed structure out of the beam path, so it does not block the beam. It is widely used in home
2623:
891:
is determined by the feed antenna. In order to achieve maximum gain, both feed antennas (transmitting and receiving) must have the same polarization. For example, a vertical dipole feed antenna will radiate a beam of radio waves with their electric field vertical, called
2032:
640:. It is sometimes used to prevent interference in terrestrial microwave links, where several antennas using the same frequency are located close together. The shroud is coated inside with microwave absorbent material. Shrouds can reduce back lobe radiation by 10 dB.
364:
A shiny metal parabolic reflector can also focus the sun's rays. Since most dishes could concentrate enough solar energy on the feed structure to severely overheat it if they happened to be pointed at the sun, solid reflectors are always given a coat of flat paint.
800:
secondary reflector at the focus of the dish. The radio waves from the feed reflect off the secondary reflector to the dish, which reflects them forward again, forming the outgoing beam. An advantage of this configuration is that the feed, with its waveguides and
2754:
2639:
1784:
1108:
2463:
1308:
is a catchall variable which accounts for various losses that reduce the gain of the antenna from the maximum that could be achieved with the given aperture. The major factors reducing the aperture efficiency in parabolic antennas are:
842:(small pumpkin-shaped surface) on spillover. Left: with a low gain feed antenna, significant parts of its radiation fall outside the dish. Right: with a higher gain feed, almost all its radiation is emitted within the angle of the dish.
2734:
2651:
393:
and
Gregorian, a secondary reflector is used to direct the energy into the parabolic reflector from a feed antenna located away from the primary focal point. The feed antenna is connected to the associated radio-frequency (RF)
2184:
723: – In order to produce an arbitrary shaped beam, instead of one feed horn, an array of feed horns clustered around the focal point can be used. Array-fed antennas are often used on communication satellites, particularly
762:
located in front of the dish at the focus, on the beam axis, pointed back toward the dish. A disadvantage of this type is that the feed and its supports block some of the beam, which limits the aperture efficiency to only
962:
In the
Cassegrain and Gregorian antennas, the presence of two reflecting surfaces in the signal path offers additional possibilities for improving performance. When the highest performance is required, a technique called
783:
dishes, which are small enough that the feed structure would otherwise block a significant percentage of the signal. Offset feed can also be used in multiple reflector designs such as the
Cassegrain and Gregorian,
2822:
constructed the world's first parabolic reflector antenna in 1888. The antenna was a cylindrical parabolic reflector made of zinc sheet metal supported by a wooden frame, and had a spark-gap excited 26 cm
1573:
176:
during his discovery of radio waves in 1887. He used cylindrical parabolic reflectors with spark-excited dipole antennas at their foci for both transmitting and receiving during his historic experiments.
2719:
2553:
2675:
1920:
330:, the shape of the dish needs to be accurate within a small fraction of a wavelength, around one sixteenth wavelength, to ensure the waves from different parts of the antenna arrive at the focus
2831:
of 0.12 meters, and was used at an operating frequency of about 450 MHz. With two such antennas, one used for transmitting and the other for receiving, Hertz demonstrated the existence of
1837:
2687:
2905:
communication networks, which carried telephone calls and television programs across continents. The first parabolic antenna used for satellite communications was constructed in 1962 at
1272:, the higher the gain. The gain increases with the square of the ratio of aperture width to wavelength, so large parabolic antennas, such as those used for spacecraft communication and
1913:
1875:
1639:
2949:, capable of calculating the radiation pattern of parabolic antennas—has led to the development of sophisticated asymmetric, multi-reflector and multi-feed designs in recent years.
2699:
1463:
636: – Sometimes a cylindrical metal shield is attached to the rim of the dish. The shroud shields the antenna from radiation from angles outside the main beam axis, reducing the
1499:
antenna at 2.4 GHz, the beamwidth was 0.028°. Since parabolic antennas can produce very narrow beams, aiming them can be a problem. Some parabolic dishes are equipped with a
2839:
some 22 years earlier. However, the early development of radio was limited to lower frequencies at which parabolic antennas were unsuitable, and they were not widely used until
1178:
1012:
2493:
2313:
2525:
2388:
2355:
2067:
2663:
1472:
is a factor which varies slightly depending on the shape of the reflector and the feed illumination pattern. For an ideal uniformly illuminated parabolic reflector and
727:, to create a downlink radiation pattern to cover a particular continent or coverage area. They are often used with secondary reflector antennas such as the Cassegrain.
3150:
2227:
1222:
420:
is required to conduct the microwaves between the feed antenna and transmitter or receiver. Because of the high cost of waveguide runs, in many parabolic antennas the
2247:
650: – The reflector is curved in only one direction and flat in the other. The radio waves come to a focus not at a point but along a line. The feed is sometimes a
2381:
2870:
was demonstrated using 3.0-meter (10 ft) diameter dishes. The first large parabolic antenna, a 9 m dish, was built in 1937 by pioneering radio astronomer
2278:
1251:
2545:
2207:
1613:
1200:
1134:
887:
The pattern of electric and magnetic fields at the mouth of a parabolic antenna is simply a scaled-up image of the fields radiated by the feed antenna, so the
1293:
4955:
95:
reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest
2075:
1627:
1296:
in southwest China, which has an effective aperture of about 300 meters. The gain of this dish at 3 GHz is roughly 90 million, or 80 dBi.
3260:
3017:
3771:
2780:
1336:, where the feed antenna is located to one side, outside the beam area. The aperture efficiency for these types of antennas can reach 0.7 to 0.8.
991:
4243:
4564:
2862:
used parabolic reflectors during the 1930s in investigations of UHF transmission from his boat in the
Mediterranean. In 1931, a 1.7 GHz
247:
beam along the axis of the reflector. Conversely, an incoming plane wave parallel to the axis will be focused to a point at the focal point.
3191:
805:" electronics does not have to be suspended in front of the dish, so it is used for antennas with complicated or bulky feeds, such as large
5663:
5635:
5630:
4655:
3430:
302:
994:(FAST) in Guangdzou, China. With an effective aperture of 300 meters, it is the largest filled aperture parabolic antenna in the world.
1512:
1506:
There is an inverse relation between gain and beam width. By combining the beamwidth equation with the gain equation, the relation is:
695: – Used in search radars, this is a long narrow antenna shaped like the letter "C". It radiates a narrow vertical fan-shaped beam.
258:
suspended in front of the reflector at its focus, pointed back toward the reflector. The reflector is a metallic surface formed into a
3338:"RF Design and Predicted Performance for a Future 34-Meter Shaped Dual-Reflector Antenna System Using the Common Aperture XS Feedhorn"
4620:
4590:
3879:
3275:
1394:, usually much smaller, in other directions. Since the reflector aperture of parabolic antennas is much larger than the wavelength,
1002:, which is the ratio of the power received by the antenna from a source along its beam axis to the power received by a hypothetical
547:
2618:{\displaystyle \theta _{0}\approx {\frac {1.22\lambda }{D}}\,{\text{(in radians)}}={\frac {70\lambda }{D}}\,{\text{(in degrees)}}}
4585:
3682:
3567:
628:
truncated with a circular rim. This is the most common type. It radiates a narrow pencil-shaped beam along the axis of the dish.
2027:{\displaystyle E=\int \limits _{0}^{2\pi }d\theta \int \limits _{0}^{\rho _{0}}e^{2\pi i\rho \cos \theta l/\lambda }\rho d\rho }
1350:
For theoretical considerations of mutual interference (at frequencies between 2 and approximately 30 GHz; typically in the
5735:
5657:
4207:
3049:
2761:
1402:, in the opposite direction to the main lobe, due to the spillover radiation from the feed antenna that misses the reflector.
5652:
5642:
5622:
5424:
3525:
3440:
3408:
3381:
3371:
3244:
3201:
3001:
3218:
3650:
3515:
2933:
launched in 1977 is currently 24.2 billion kilometers from Earth, the furthest manmade object in space, and it's 3.7 meter
4789:
2645:
The first parabolic antenna, built by
Heinrich Hertz in 1888. Part cutaway to show 450 MHz spark-excited dipole feed.
5714:
5647:
5493:
4518:
3610:
262:
of revolution and usually truncated in a circular rim that forms the diameter of the antenna. In a transmitting antenna,
131:
2281:
2037:
5419:
4608:
3285:
3059:
439:
An advantage of parabolic antennas is that most of the structure of the antenna (all of it except the feed antenna) is
5513:
4248:
4149:
4111:
3929:
3470:
3163:
3133:
2906:
1791:
5298:
4846:
4648:
3644:
3542:
2898:—the first version of which was completed in 1962—is currently the world's largest fully steerable parabolic dish.
2741:
903:
To increase the data rate, some parabolic antennas transmit two separate radio channels on the same frequency with
466:
103:, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the
1779:{\displaystyle E=\int \int {\frac {A}{r_{1}}}e^{j(\omega t-\beta r_{1})}dS=\int \int e^{2\pi i(lx+my)/\lambda }dS}
1595:
with uniform illuminated aperture is essentially equivalent to that from a circular aperture of the same diameter
5745:
5409:
3398:
2946:
1136:
is the area of the antenna aperture, that is, the mouth of the parabolic reflector. For a circular dish antenna,
490:
5404:
2918:
1880:
1842:
1255:
896:. The receiving feed antenna must also have vertical polarization to receive them; if the feed is horizontal (
5429:
4472:
448:
433:
2945:
is still able to communicate with ground stations. The advent of computer design tools in the 1970s—such as
2858:, both to increase range and make radio transmissions more secure from interception. Italian radio pioneer
1342: – Random surface errors in the shape of the reflector reduce efficiency. This loss is approximated by
424:
electronics of the receiver is located at the feed antenna, and the received signal is converted to a lower
5704:
5465:
5362:
4905:
4700:
4672:
4569:
4293:
3751:
1430:
1362:
S.465 is used to calculate the interference, which will include the likely sidelobes for off-axis effects.
1276:, can have extremely high gain. Applying the above formula to the 25-meter-diameter antennas often used in
934:
If the signal from one polarization channel is received by the oppositely polarized antenna, it will cause
871:
417:
3301:
Galindo, V. (1964). "Design of dual-reflector antennas with arbitrary phase and amplitude distributions".
326:, so screen reflectors are often used to reduce weight and wind loads on the dish. To achieve the maximum
5694:
5201:
4641:
4345:
3776:
3675:
942:. The ability of an antenna to keep these orthogonal channels separate is measured by a parameter called
916:
123:) frequencies, at which the wavelengths are small enough that conveniently sized reflectors can be used.
5553:
5475:
5414:
5121:
920:
724:
708:
166:
1420:
at which the power drops to one-half (-3 dB) its maximum value. For parabolic antennas, the HPBW
5740:
5325:
5286:
5131:
5031:
4960:
4893:
4720:
4497:
4197:
4182:
4014:
2895:
1103:{\displaystyle G={\frac {4\pi A}{\lambda ^{2}}}e_{A}=\left({\frac {\pi d}{\lambda }}\right)^{2}e_{A}}
951:
5684:
4926:
4861:
4814:
4774:
4513:
4202:
4158:
4009:
3919:
2874:
in his backyard, and the sky survey he did with it was one of the events that founded the field of
2458:{\displaystyle \theta _{0}=\arcsin {\frac {3.83\lambda }{\pi D}}=\arcsin {\frac {1.22\lambda }{D}}}
1139:
211:
are all the same length. Thus, a spherical wavefront emitted by a feed antenna at the dish's focus
143:
24:
2827:
as a feed antenna along the focal line. Its aperture was 2 meters high by 1.2 meters wide, with a
1398:
usually causes many narrow sidelobes, so the sidelobe pattern is complex. There is also usually a
169:
receivers, parabolic antennas have become a common feature of the landscapes of modern countries.
5523:
5508:
5352:
5303:
5226:
5126:
4804:
4690:
4685:
4253:
4187:
3909:
3718:
2776:
2471:
2291:
1351:
897:
806:
436:. Similarly, in transmitting dishes, the microwave transmitter may be located at the feed point.
2498:
2318:
2043:
915:
signals are transmitted from the satellite on two separate channels at the same frequency using
5445:
5231:
5046:
4991:
4986:
4799:
4764:
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4432:
4258:
4091:
4029:
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3668:
3568:"Historical review of reflector antenna systems developed for satellite communication by MELCO"
3487:
2902:
425:
135:
32:
4492:
3123:
3089:
2779:, Puerto Rico, at 305 metres (1,001 feet) the largest parabolic dish until 2016 when China's
2212:
1207:
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5151:
5116:
5036:
5016:
4938:
4826:
4747:
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4142:
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1619:
939:
893:
509:
314:
237:
4680:
3627:
2360:
1280:
arrays and satellite ground antennas at a wavelength of 21 cm (1.42 GHz, a common
232:
The operating principle of a parabolic antenna is that a point source of radio waves at the
157:
antennas, which need to transmit a narrow beam of radio waves to locate objects like ships,
5261:
5221:
5191:
4948:
4883:
4705:
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4172:
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3801:
3617:
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3310:
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2891:
2808:
2256:
1229:
998:
The directive qualities of an antenna are measured by a dimensionless parameter called its
912:
888:
862:
section below). Radiation from the feed that falls outside the edge of the dish is called
780:
120:
112:
341:
A reflector made of a grill of parallel wires or bars oriented in one direction acts as a
184:
Parabolic antennas are based on the geometrical property of the paraboloid that the paths
107:
of the radio waves used, so parabolic antennas are used in the high frequency part of the
47:-type feed, transmits at 6 Ghz and receives at 4 Ghz with a gain of 64.2 dB
8:
5271:
5211:
4970:
4932:
4730:
4715:
4548:
4361:
4283:
3974:
3866:
3821:
2972:
2926:
2855:
2836:
2804:
2796:
1299:
821: – Similar to the Cassegrain design except that the secondary reflector is concave (
796:, the feed is located on or behind the dish, and radiates forward, illuminating a convex
774:
346:
251:
180:
60:
3356:
3337:
3314:
2795:, where the power of a parabolic mirror to focus light into a beam has been known since
2745:
5498:
5455:
5386:
5256:
5186:
5161:
5096:
4943:
4664:
4116:
3964:
3904:
3899:
3796:
3708:
3254:
3011:
2800:
2681:
A 20 MHz shortwave parabolic wire antenna built by
Marconi at Herndon, UK, in 1922
2530:
2192:
1598:
1343:
1185:
1119:
1003:
793:
390:
44:
3578:
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has to be tailored to the shape of the dish, because it has a strong influence on the
5538:
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5374:
5357:
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5166:
4996:
4965:
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4725:
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3914:
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3404:
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3281:
3240:
3197:
3159:
3129:
3055:
2997:
2859:
1500:
1496:
1417:
1374:
1289:
847:
839:
406:
342:
282:
274:
127:
5206:
2725:
1480:
would be 57.3 (the number of degrees in a radian). For a typical parabolic antenna,
1386:
In parabolic antennas, virtually all the power radiated is concentrated in a narrow
5543:
5503:
5483:
5450:
5379:
5337:
5251:
5106:
5091:
5066:
5041:
5001:
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4533:
4212:
4135:
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3816:
3318:
583:
374:
266:
241:
139:
2179:{\displaystyle E(\theta )={\frac {2\lambda }{\pi D}}{\frac {J_{1}}{\sin \theta }}}
5171:
5026:
4794:
4769:
4757:
4407:
4303:
4278:
4273:
4177:
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4044:
4019:
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3761:
3741:
3726:
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frequency), yields an approximate maximum gain of 140,000 times or about 52 dBi (
1281:
1277:
1273:
810:
513:
263:
147:
56:
2657:
Augusto Righi's experimental 12 GHz microwave transmitter and receiver 1894
1410:
The angular width of the beam radiated by high-gain antennas is measured by the
559:
5369:
5241:
5216:
5176:
5146:
5021:
4856:
4809:
4784:
4742:
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4192:
4106:
4039:
4024:
3999:
3874:
3831:
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3756:
2958:
2824:
2819:
2693:
Marconi 70MHz rotating parabolic maritime radio beacon on
Inchkeith Island 1925
1623:
1488:
1320:
falls outside the edge of the dish and so does not contribute to the main beam.
924:
651:
399:
378:
350:
310:
286:
233:
173:
162:
108:
3638:
931:, oriented at right angles. Each antenna is connected to a separate receiver.
5729:
5518:
5291:
5281:
5196:
5086:
5081:
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5056:
4878:
4737:
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4233:
4086:
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3969:
3924:
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3322:
1492:
429:
403:
3632:
Online pointing utility using google maps, and each satellite channel list:
1615:
in an infinite metal plate with a uniform plane wave incident on the plate.
5396:
5236:
5181:
5111:
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5011:
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1631:
1317:
999:
981:
851:
802:
759:
734:
601:
421:
382:
327:
278:
96:
19:
1416:(HPBW), which is the angular separation between the points on the antenna
43:, the biggest facility for satellite communication in the world. It has a
5596:
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5156:
5141:
5101:
5061:
4920:
4457:
4391:
3884:
3736:
2871:
2847:
2791:
The idea of using parabolic reflectors for radio antennas was taken from
2710:
1395:
797:
395:
270:
138:
links that carry telephone and television signals between nearby cities,
88:
84:
879:
less at the dish edge than its maximum value at the center of the dish.
541:
Vertical "orange peel" antenna for military height finder radar, Germany
5601:
5308:
5006:
4915:
4871:
4841:
4819:
4422:
2851:
2832:
2812:
2799:. The designs of some specific types of parabolic antenna, such as the
1630:
integral over the circular aperture. It can also be determined through
1592:
1412:
1269:
986:
904:
625:
361:, it helps filter out noise in the receiver and reduces false returns.
323:
259:
244:
104:
92:
68:
3656:
PlutoDirect.co.uk : Low prices in
Satellite & CCTV Equipments
1260:
The aperture efficiency of typical parabolic antennas is 0.55 to 0.70.
571:
472:
Shrouded microwave relay dishes on a communications tower in
Australia
297:
5586:
5051:
4866:
4633:
4376:
3939:
3846:
2930:
1387:
935:
928:
834:
822:
444:
440:
410:
386:
358:
306:
255:
165:. They are also often used for weather detection. With the advent of
116:
100:
2917:
satellite. The
Cassegrain antenna was developed in Japan in 1963 by
2669:
Guglielmo Marconi's 1.2 GHz spark transmitter and receiver 1895
1578:
1495:(4 GHz), this formula gives a beamwidth of about 2.6°. For the
5581:
5571:
5488:
5313:
5136:
4477:
4442:
4437:
4427:
4417:
4412:
4340:
4288:
4096:
3894:
3700:
3485:
2968:
2910:
1399:
1391:
969:
867:
637:
331:
158:
72:
64:
2901:
During the 1960s, dish antennas became widely used in terrestrial
2748:, Germany in 1972, the largest aperture steerable dish until 2000.
1568:{\displaystyle G=\left({\frac {\pi k}{\theta }}\right)^{2}\ e_{A}}
5576:
5561:
4779:
4482:
4467:
4386:
4366:
4335:
4325:
3193:
Microwave transmission networks: Planning, Design, and Deployment
2914:
1285:
876:
40:
36:
3660:
3655:
3622:
703:
502:
83:. The main advantage of a parabolic antenna is that it has high
5606:
5566:
4888:
4538:
4487:
4381:
4330:
4315:
4238:
4228:
4070:
3605:
2938:
2934:
2792:
2250:
1292:
level). The largest parabolic dish antenna in the world is the
972:, and patterns with a central "hole" to reduce feed shadowing.
478:
146:, and spacecraft communication antennas. They are also used in
3633:
1202:
is the diameter of the parabolic reflector, if it is circular.
907:
polarizations, using separate feed antennas; this is called a
565:
Airport surveillance radar antenna, Orly airport, France, 1964
416:
At the microwave frequencies used in many parabolic antennas,
5591:
5528:
4836:
4523:
4320:
4049:
2882:
2728:
radar built by Germany in WW2 had a 7.4 meter (24 foot) dish.
2253:
from the antenna's symmetry axis as shown in the figure, and
1359:
1354:) where specific antenna performance has not been defined, a
484:
A satellite television dish, an example of an offset fed dish
354:
335:
154:
3575:
ISAP2006-International Symposium on Antennas and Propagation
1390:
along the antenna's axis. The residual power is radiated in
737:, that is, how the radio waves are supplied to the antenna:
428:(IF) so it can be conducted to the receiver through cheaper
313:
under the small aluminum reflector on the boom. It radiates
5533:
2922:
947:
927:, these are received by two small monopole antennas in the
535:
353:
parallel to the grill elements. This type is often used in
1618:
The radiation-field pattern can be calculated by applying
1370:
825:) in shape. Aperture efficiency over 70% can be achieved.
553:
Early cylindrical parabolic antenna, 1931, Nauen, Germany
373:
The feed antenna at the reflector's focus is typically a
338:
structure behind them to provide the required stiffness.
1253:
is a dimensionless parameter between 0 and 1 called the
3345:
Telecommunications and Data Acquisition Progress Report
758: – This is the most common type of feed, with the
172:
The parabolic antenna was invented by German physicist
63:, a curved surface with the cross-sectional shape of a
3639:
Animation of Propagation from a Parabolic Dish Antenna
3047:
1503:
so they can be aimed accurately at the other antenna.
733:
Parabolic antennas are also classified by the type of
609:
Parabolic antennas are distinguished by their shapes:
2556:
2533:
2501:
2474:
2391:
2363:
2321:
2294:
2259:
2235:
2215:
2209:
is the diameter of the antenna's aperture in meters,
2195:
2078:
2046:
1923:
1883:
1845:
1794:
1642:
1601:
1515:
1433:
1294:
Five-hundred-meter Aperture Spherical radio Telescope
1232:
1210:
1188:
1142:
1122:
1015:
3432:
Satellite Systems Engineering in an IPv6 Environment
954:
algorithms can often be used to decrease crosstalk.
866:
and is wasted, reducing the gain and increasing the
2843:, when microwave frequencies began to be employed.
589:"Orange peel" antenna for air search radar, Finland
496:
Cassegrain antenna on the Voyager spacecraft, 1977.
3239:. US: American Radio Relay League. p. 18.14.
3196:. US: McGraw Hill Professional. pp. 268–272.
2996:. US: American Radio Relay League. p. 19.15.
2617:
2539:
2519:
2487:
2457:
2375:
2349:
2307:
2272:
2241:
2221:
2201:
2178:
2061:
2026:
1907:
1869:
1831:
1778:
1607:
1567:
1457:
1245:
1216:
1194:
1172:
1128:
1102:
711:antenna to control the elevation angle of the beam
900:) the antenna will suffer a severe loss of gain.
153:The other large use of parabolic antennas is for
5727:
3459:Kraus, John Daniel; Marhefka, Ronald J. (2002).
1622:in a similar way to a rectangular aperture. The
813:. Aperture efficiency is on the order of 65–70%.
250:A typical parabolic antenna consists of a metal
3376:. US: John Wiley & Sons. pp. 206–207.
3054:. US: John Wiley & Sons. pp. 391–392.
2807:, come from similarly named analogous types of
2781:Five-hundred-meter Aperture Spherical Telescope
1832:{\displaystyle \beta =\omega /c=2\pi /\lambda }
992:Five Hundred Meter Aperture Spherical Telescope
3400:Satellite systems: principles and technologies
1268:, the larger the aperture is, compared to the
215:will be reflected into an outgoing plane wave
99:, meaning that they can produce the narrowest
4649:
4565:Consultative Committee for Space Data Systems
4143:
3676:
3458:
3303:IEEE Transactions on Antennas and Propagation
3148:
3083:
3081:
3079:
3077:
3075:
3073:
3071:
2288:of the radiation pattern gives the beamwidth
1377:of a German parabolic antenna. The main lobe
357:antennas. Combined with a linearly polarized
4157:
3623:Online Satellite Finder Based on Google Maps
3259:: CS1 maint: multiple names: authors list (
3048:Stutzman, Warren L.; Gary A. Thiele (2012).
3016:: CS1 maint: multiple names: authors list (
2547:. This gives the common beamwidth formulas,
1586:
516:at the University of California Berkeley, US
5664:Global telecommunications regulation bodies
3335:
3300:
5700:
4656:
4642:
4150:
4136:
3683:
3669:
3577:. Mitsubishi Electric Corp. Archived from
3185:
3183:
3181:
3179:
3177:
3175:
3087:
3068:
3043:
3041:
3039:
3037:
3035:
3033:
3031:
3029:
3027:
1582:The angle theta is normal to the aperture.
948:cross polarization interference cancelling
443:, so it can function over a wide range of
334:. Large dishes often require a supporting
301:Wire grid-type parabolic antenna used for
4591:List of communication satellite companies
3628:Antenna types: Parabolic Antenna for WiFi
3486:John C. Slater & Nathaniel H. Frank.
3424:
3422:
3420:
2609:
2585:
1908:{\displaystyle y=\rho \cdot \sin \theta }
1870:{\displaystyle x=\rho \cdot \cos \theta }
1454:
957:
858:, which determines the antenna gain (see
707:Array of multiple feed horns on a German
345:as well as a reflector. It only reflects
3509:
3507:
3505:
3503:
3501:
3499:
3369:
3363:
3189:
3149:Carr, Joseph; Hippisley, George (2012).
1577:
1369:
985:
833:
702:
600:
577:ASR-9 Airport surveillance radar antenna
309:of 2.5-2.7 GHz. It is fed by a vertical
296:
236:in front of a paraboloidal reflector of
179:
71:. The most common form is shaped like a
18:
4586:List of communications satellite firsts
3634:DishPointer - Align your satellite dish
3618:WiFi: Parabolic Dish with BiQuad feeder
3543:"Large Space Antenna Concepts for ESGP"
3280:. John Wiley and Sons. pp. 55–58.
3273:
3172:
3024:
2709:: a 9-meter (30 ft) dish built by
1626:pattern can be found by evaluating the
1316: – Some of the radiation from the
624: – The reflector is shaped like a
389:. In more complex designs, such as the
219:travelling parallel to the dish's axis
5728:
4663:
4468:Shanghai Spacecom Satellite Technology
3565:
3559:
3428:
3417:
3396:
3390:
3373:Fixed broadband wireless system design
3267:
3230:
3228:
3117:
3115:
3113:
3111:
2975:in one plane and parabolic in another)
2762:Ballistic Missile Early Warning System
2468:When the aperture is large, the angle
1006:. The gain of a parabolic antenna is:
292:
4637:
4131:
3664:
3513:
3496:
3454:
3452:
3234:
2991:
1458:{\displaystyle \theta =k\lambda /d\,}
1224:is the wavelength of the radio waves.
605:Main types of parabolic antenna feeds
508:Offset Gregorian antenna used in the
5710:
4616:
3651:Applet of gain of parabolic antenna.
3645:Parabolic reflector antenna tutorial
3121:
2985:
2971:(a quasi-parabolic antenna which is
1365:
3489:Introduction to Theoretical Physics
3225:
3142:
3108:
2913:, England, to communicate with the
2854:began to be used, interest grew in
13:
3449:
3152:Practical Antenna Handbook, 5th Ed
1180:, giving the second formula above.
240:material will be reflected into a
14:
5757:
4249:Automatic Tracking Satellite Dish
4112:Circularly disposed antenna array
3930:Folded inverted conformal antenna
3690:
3599:
3090:"The Parabolic Reflector Antenna"
3051:Antenna Theory and Design, 3rd Ed
2783:was built. It collapsed in 2020.
2040:gives the electric field pattern
1264:It can be seen that, as with any
944:cross polarization discrimination
5709:
5699:
5690:
5689:
5678:
5299:Free-space optical communication
4615:
4604:
4603:
3604:
3540:
2769:
2753:
2733:
2718:
2698:
2686:
2674:
2662:
2650:
2638:
582:
570:
558:
546:
534:
501:
489:
477:
465:
3534:
3479:
3329:
3294:
2886:parabolic dishes were built as
2764:, Alaska, 1961, 400 by 165 feet
882:
829:
368:
142:links for data communications,
126:Parabolic antennas are used as
3277:Introduction to RF Propagation
3237:The ARRL Antenna Book, 19th Ed
3210:
2994:The ARRL Antenna Book, 19th Ed
2760:Radar antenna of US Air Force
2514:
2508:
2338:
2332:
2159:
2147:
2130:
2127:
2088:
2082:
2056:
2050:
1915:. Taking account of symmetry,
1757:
1739:
1705:
1680:
527:Shaped-beam parabolic antennas
87:. It functions similarly to a
1:
5736:Radio frequency antenna types
3462:Antennas for all applications
3435:. US: CRC Press. p. 78.
3403:. US: Springer. p. 267.
3125:Antennas and Wave Propagation
3088:Bevelacqua, Peter J. (2011).
2979:
2229:is the wavelength in meters,
1173:{\displaystyle A=\pi d^{2}/4}
434:low-noise block downconverter
132:point-to-point communications
5685:Telecommunication portal
5466:Telecommunications equipment
4570:ETSI Satellite Digital Radio
4294:Very-small-aperture terminal
3752:Dielectric resonator antenna
3235:Straw, R. Dean, Ed. (2000).
3096:. Antenna-Theory.com website
2992:Straw, R. Dean, Ed. (2000).
2835:which had been predicted by
1405:
23:A 28.5 meter parabolic
7:
5202:Alexander Stepanovich Popov
4346:Digital audio radio service
4254:Motor-driven Satellite dish
3370:Anderson, Harry R. (2003).
3128:. Pearson Education India.
2952:
2488:{\displaystyle \theta _{0}}
2308:{\displaystyle \theta _{0}}
2282:first-order Bessel function
2038:first-order Bessel function
1839:. Using polar coordinates,
1591:The radiation from a large
838:Effect of the feed antenna
725:direct broadcast satellites
10:
5762:
4906:Telecommunications history
2892:Green Bank Radio Telescope
2866:telephone link across the
2742:Effelsberg radio telescope
2628:
2527:is approximately equal to
2520:{\displaystyle \arcsin(x)}
2350:{\displaystyle J_{1}(x)=0}
2062:{\displaystyle E(\theta )}
979:
921:left circular polarization
709:airport surveillance radar
134:, in applications such as
75:and is popularly called a
5673:
5615:
5552:
5514:Public Switched Telephone
5474:
5438:
5395:
5336:
5326:telecommunication circuit
5287:Fiber-optic communication
5270:
5032:Francis Blake (telephone)
4979:
4827:Optical telecommunication
4671:
4599:
4578:
4557:
4506:
4401:Relay satellite companies
4400:
4354:
4302:
4221:
4198:High-throughput satellite
4183:Satellite Internet access
4165:
4063:
4015:Regenerative loop antenna
3865:
3717:
3699:
3517:Microwave horns and feeds
3274:Seybold, John S. (2005).
3219:Microwave Horns and Feeds
3190:Lehpamer, Harvey (2010).
2896:Green Bank, West Virginia
2815:during the 15th century.
2811:, which were invented by
2740:The 100 meter (300 foot)
1587:Radiation pattern formula
952:digital signal processing
909:dual polarization antenna
859:
227:
167:home satellite television
5425:Orbital angular-momentum
4862:Satellite communications
4701:Communications satellite
4159:Satellite communications
4010:Reflective array antenna
3920:Corner reflector antenna
3566:Makino, Shigero (2006).
3548:. Rockwell International
3514:Olver, A. David (1994).
3323:10.1109/TAP.1964.1138236
2284:. Determining the first
2222:{\displaystyle \lambda }
1358:based on Recommendation
1217:{\displaystyle \lambda }
596:
402:equipment by means of a
381:or (more often) a small
144:satellite communications
25:satellite communications
5304:Molecular communication
5127:Gardiner Greene Hubbard
4956:Undersea telegraph line
4691:Cable protection system
4507:Satellite manufacturers
3910:Collinear antenna array
3429:Minoli, Daniel (2009).
3122:Raju, G. S. N. (2006).
2777:Arecibo radio telescope
2713:in his backyard in 1937
2242:{\displaystyle \theta }
1352:Fixed Satellite Service
1324:Feed illumination taper
975:
898:horizontal polarization
807:satellite communication
458:Dish parabolic antennas
5746:Satellite broadcasting
5446:Communication protocol
5232:Charles Sumner Tainter
5047:Walter Houser Brattain
4992:Edwin Howard Armstrong
4800:Information revolution
4092:Reconfigurable antenna
4055:Yagi–Uda antenna
4030:Short backfire antenna
3767:Folded unipole antenna
3520:. US: IET. p. 3.
3397:Pattan, Bruno (1993).
3216:A. David Olver (1994)
2619:
2541:
2521:
2489:
2459:
2377:
2376:{\displaystyle x=3.83}
2351:
2309:
2274:
2243:
2223:
2203:
2180:
2063:
2028:
1975:
1947:
1909:
1871:
1833:
1780:
1632:Fresnel zone equations
1628:Fraunhofer diffraction
1609:
1583:
1569:
1487:For a typical 2 meter
1459:
1383:
1247:
1218:
1196:
1174:
1130:
1104:
995:
965:dual reflector shaping
958:Dual reflector shaping
843:
712:
606:
426:intermediate frequency
349:radio waves, with the
318:
273:is supplied through a
224:
48:
33:Raisting Earth Station
29:Erdfunkstelle Raisting
5420:Polarization-division
5152:Narinder Singh Kapany
5117:Erna Schneider Hoover
5037:Jagadish Chandra Bose
5017:Alexander Graham Bell
4748:online video platform
3747:Crossed field antenna
3613:at Wikimedia Commons
2620:
2542:
2522:
2490:
2460:
2378:
2352:
2310:
2275:
2273:{\displaystyle J_{1}}
2244:
2224:
2204:
2181:
2064:
2029:
1954:
1930:
1910:
1872:
1834:
1781:
1610:
1581:
1570:
1484:is approximately 70.
1460:
1413:half-power beam width
1373:
1248:
1246:{\displaystyle e_{A}}
1219:
1197:
1175:
1131:
1105:
989:
940:signal-to-noise ratio
894:vertical polarization
837:
706:
692:"Orange peel" antenna
604:
510:Allen Telescope Array
300:
183:
22:
5262:Vladimir K. Zworykin
5222:Almon Brown Strowger
5192:Charles Grafton Page
4847:Prepaid mobile phone
4775:Electrical telegraph
4173:Satellite television
4064:Application-specific
3955:Log-periodic antenna
3827:Rubber ducky antenna
3802:Inverted vee antenna
3777:Ground-plane antenna
3336:Willams, WF (1983).
3309:(4). IEEE: 403–408.
2964:Satellite television
2931:Voyager 1 spacecraft
2856:directional antennas
2809:reflecting telescope
2554:
2531:
2499:
2472:
2389:
2361:
2319:
2292:
2257:
2233:
2213:
2193:
2076:
2044:
1921:
1881:
1843:
1792:
1640:
1599:
1513:
1431:
1230:
1208:
1186:
1140:
1120:
1013:
913:satellite television
781:satellite television
668:Shaped-beam antennas
315:vertically polarized
5212:Johann Philipp Reis
4971:Wireless revolution
4933:The Telephone Cases
4790:Hydraulic telegraph
4558:Trade organizations
4549:Thales Alenia Space
4362:Astra Digital Radio
4355:Broadcast companies
4284:Satellite data unit
3975:Offset dish antenna
3822:Random wire antenna
3647:Theory and practice
3357:1983TDAPR..73...74W
3315:1964ITAP...12..403G
2943:(see picture above)
2941:Cassegrain antenna
2927:Mitsubishi Electric
2881:The development of
2837:James Clerk Maxwell
2797:classical antiquity
1300:Aperture efficiency
1256:aperture efficiency
870:, possibly causing
856:aperture efficiency
432:. This is called a
293:Parabolic reflector
252:parabolic reflector
61:parabolic reflector
5410:Frequency-division
5387:Telephone exchange
5257:Charles Wheatstone
5187:Jun-ichi Nishizawa
5162:Innocenzo Manzetti
5097:Reginald Fessenden
4832:Optical telegraphy
4665:Telecommunications
4377:Sirius XM Holdings
4268:Parabolic antennas
4117:Television antenna
3965:Microstrip antenna
3905:Choke ring antenna
3900:Cassegrain antenna
3797:Inverted-F antenna
3709:Isotropic radiator
3611:Parabolic antennas
2615:
2537:
2517:
2495:is very small, so
2485:
2455:
2373:
2347:
2305:
2270:
2239:
2219:
2199:
2176:
2059:
2024:
1905:
1867:
1829:
1776:
1620:Huygens' principle
1605:
1584:
1565:
1455:
1384:
1243:
1214:
1192:
1170:
1126:
1100:
996:
938:that degrades the
844:
794:Cassegrain antenna
713:
607:
347:linearly polarized
319:
225:
128:high-gain antennas
49:
5723:
5722:
5461:Store and forward
5456:Data transmission
5370:Network switching
5321:Transmission line
5167:Guglielmo Marconi
5132:Internet pioneers
4997:Mohamed M. Atalla
4966:Whistled language
4631:
4630:
4188:Amateur satellite
4125:
4124:
4102:Reference antenna
3995:Parabolic antenna
3915:Conformal antenna
3837:Turnstile antenna
3732:Biconical antenna
3609:Media related to
3527:978-0-7803-1115-2
3442:978-1-4200-7868-8
3410:978-0-442-01357-8
3383:978-0-470-84438-0
3246:978-0-87259-817-1
3203:978-0-07-170122-8
3003:978-0-87259-817-1
2860:Guglielmo Marconi
2818:German physicist
2613:
2607:
2589:
2583:
2540:{\displaystyle x}
2453:
2429:
2202:{\displaystyle D}
2174:
2112:
1670:
1608:{\displaystyle D}
1554:
1540:
1418:radiation pattern
1375:Radiation pattern
1366:Radiation pattern
1356:reference antenna
1330:Aperture blockage
1195:{\displaystyle d}
1129:{\displaystyle A}
1078:
1045:
1004:isotropic antenna
848:radiation pattern
840:radiation pattern
680:Shaped reflectors
407:transmission line
343:polarizing filter
283:transmission line
275:transmission line
53:parabolic antenna
5753:
5741:Antennas (radio)
5713:
5712:
5703:
5702:
5693:
5692:
5683:
5682:
5681:
5554:Notable networks
5544:Wireless network
5484:Cellular network
5476:Types of network
5451:Computer network
5338:Network topology
5252:Thomas A. Watson
5107:Oliver Heaviside
5092:Philo Farnsworth
5067:Daniel Davis Jr.
5042:Charles Bourseul
5002:John Logie Baird
4711:Data compression
4706:Computer network
4658:
4651:
4644:
4635:
4634:
4619:
4618:
4607:
4606:
4534:Northrop Grumman
4213:Carriage dispute
4152:
4145:
4138:
4129:
4128:
4076:Corner reflector
3890:Beverage antenna
3852:Umbrella antenna
3817:Monopole antenna
3772:Franklin antenna
3685:
3678:
3671:
3662:
3661:
3608:
3594:
3592:
3590:
3589:
3583:
3572:
3563:
3557:
3556:
3554:
3553:
3547:
3538:
3532:
3531:
3511:
3494:
3493:
3483:
3477:
3476:
3456:
3447:
3446:
3426:
3415:
3414:
3394:
3388:
3387:
3367:
3361:
3360:
3342:
3333:
3327:
3326:
3298:
3292:
3291:
3271:
3265:
3264:
3258:
3250:
3232:
3223:
3214:
3208:
3207:
3187:
3170:
3169:
3157:
3146:
3140:
3139:
3119:
3106:
3105:
3103:
3101:
3085:
3066:
3065:
3045:
3022:
3021:
3015:
3007:
2989:
2890:. The 100-meter
2888:radio telescopes
2773:
2757:
2746:Bad Münstereifel
2737:
2722:
2702:
2690:
2678:
2666:
2654:
2642:
2624:
2622:
2621:
2616:
2614:
2611:
2608:
2603:
2595:
2590:
2587:
2584:
2579:
2571:
2566:
2565:
2546:
2544:
2543:
2538:
2526:
2524:
2523:
2518:
2494:
2492:
2491:
2486:
2484:
2483:
2464:
2462:
2461:
2456:
2454:
2449:
2441:
2430:
2428:
2420:
2412:
2401:
2400:
2382:
2380:
2379:
2374:
2356:
2354:
2353:
2348:
2331:
2330:
2314:
2312:
2311:
2306:
2304:
2303:
2279:
2277:
2276:
2271:
2269:
2268:
2249:is the angle in
2248:
2246:
2245:
2240:
2228:
2226:
2225:
2220:
2208:
2206:
2205:
2200:
2185:
2183:
2182:
2177:
2175:
2173:
2162:
2143:
2126:
2125:
2115:
2113:
2111:
2103:
2095:
2068:
2066:
2065:
2060:
2033:
2031:
2030:
2025:
2014:
2013:
2009:
1974:
1973:
1972:
1962:
1946:
1938:
1914:
1912:
1911:
1906:
1876:
1874:
1873:
1868:
1838:
1836:
1835:
1830:
1825:
1808:
1785:
1783:
1782:
1777:
1769:
1768:
1764:
1709:
1708:
1704:
1703:
1671:
1669:
1668:
1656:
1614:
1612:
1611:
1606:
1574:
1572:
1571:
1566:
1564:
1563:
1552:
1551:
1550:
1545:
1541:
1536:
1528:
1464:
1462:
1461:
1456:
1450:
1274:radio telescopes
1266:aperture antenna
1252:
1250:
1249:
1244:
1242:
1241:
1223:
1221:
1220:
1215:
1201:
1199:
1198:
1193:
1179:
1177:
1176:
1171:
1166:
1161:
1160:
1135:
1133:
1132:
1127:
1109:
1107:
1106:
1101:
1099:
1098:
1089:
1088:
1083:
1079:
1074:
1066:
1056:
1055:
1046:
1044:
1043:
1034:
1023:
811:radio telescopes
586:
574:
562:
550:
538:
505:
493:
481:
469:
379:half-wave dipole
377:type, such as a
148:radio telescopes
140:wireless WAN/LAN
67:, to direct the
5761:
5760:
5756:
5755:
5754:
5752:
5751:
5750:
5726:
5725:
5724:
5719:
5679:
5677:
5669:
5611:
5548:
5470:
5434:
5391:
5340:
5332:
5273:
5266:
5172:Robert Metcalfe
5027:Tim Berners-Lee
4975:
4795:Information Age
4667:
4662:
4632:
4627:
4595:
4574:
4553:
4529:Lockheed Martin
4502:
4408:AST SpaceMobile
4396:
4350:
4304:Satellite radio
4298:
4279:Satellite modem
4274:Satellite phone
4259:Multi-satellite
4217:
4203:Relay satellite
4178:Satellite radio
4161:
4156:
4126:
4121:
4082:Evolved antenna
4059:
4045:Vivaldi antenna
4020:Rhombic antenna
3945:Helical antenna
3935:Fractal antenna
3880:AS-2259 Antenna
3861:
3792:Helical antenna
3762:Discone antenna
3742:Coaxial antenna
3727:Batwing antenna
3719:Omnidirectional
3713:
3695:
3689:
3602:
3597:
3593:on ISAP website
3587:
3585:
3581:
3570:
3564:
3560:
3551:
3549:
3545:
3541:Love, Allan W.
3539:
3535:
3528:
3512:
3497:
3484:
3480:
3473:
3465:. McGraw-Hill.
3457:
3450:
3443:
3427:
3418:
3411:
3395:
3391:
3384:
3368:
3364:
3340:
3334:
3330:
3299:
3295:
3288:
3272:
3268:
3252:
3251:
3247:
3233:
3226:
3215:
3211:
3204:
3188:
3173:
3166:
3158:. McGraw-Hill.
3155:
3147:
3143:
3136:
3120:
3109:
3099:
3097:
3086:
3069:
3062:
3046:
3025:
3009:
3008:
3004:
2990:
2986:
2982:
2955:
2903:microwave relay
2876:radio astronomy
2868:English Channel
2864:microwave relay
2789:
2788:
2787:
2784:
2774:
2765:
2758:
2749:
2738:
2729:
2723:
2714:
2707:radio telescope
2703:
2694:
2691:
2682:
2679:
2670:
2667:
2658:
2655:
2646:
2643:
2631:
2626:
2610:
2596:
2594:
2586:
2572:
2570:
2561:
2557:
2555:
2552:
2551:
2532:
2529:
2528:
2500:
2497:
2496:
2479:
2475:
2473:
2470:
2469:
2442:
2440:
2421:
2413:
2411:
2396:
2392:
2390:
2387:
2386:
2362:
2359:
2358:
2326:
2322:
2320:
2317:
2316:
2299:
2295:
2293:
2290:
2289:
2264:
2260:
2258:
2255:
2254:
2234:
2231:
2230:
2214:
2211:
2210:
2194:
2191:
2190:
2187:
2163:
2139:
2121:
2117:
2116:
2114:
2104:
2096:
2094:
2077:
2074:
2073:
2045:
2042:
2041:
2005:
1980:
1976:
1968:
1964:
1963:
1958:
1939:
1934:
1922:
1919:
1918:
1882:
1879:
1878:
1844:
1841:
1840:
1821:
1804:
1793:
1790:
1789:
1760:
1729:
1725:
1699:
1695:
1676:
1672:
1664:
1660:
1655:
1641:
1638:
1637:
1600:
1597:
1596:
1589:
1559:
1555:
1546:
1529:
1527:
1523:
1522:
1514:
1511:
1510:
1446:
1432:
1429:
1428:
1408:
1368:
1344:Ruze's Equation
1307:
1282:radio astronomy
1278:radio telescope
1237:
1233:
1231:
1228:
1227:
1209:
1206:
1205:
1187:
1184:
1183:
1162:
1156:
1152:
1141:
1138:
1137:
1121:
1118:
1117:
1094:
1090:
1084:
1067:
1065:
1061:
1060:
1051:
1047:
1039:
1035:
1024:
1022:
1014:
1011:
1010:
984:
978:
960:
911:. For example,
885:
832:
720:Arrays of feeds
657:pillbox antenna
599:
594:
593:
592:
591:
590:
587:
579:
578:
575:
567:
566:
563:
555:
554:
551:
543:
542:
539:
530:
529:
521:
520:
519:
518:
517:
514:radio telescope
506:
498:
497:
494:
486:
485:
482:
474:
473:
470:
461:
460:
371:
305:data link at a
295:
264:radio frequency
230:
209:
205:
201:
197:
193:
189:
163:guided missiles
136:microwave relay
17:
16:Type of antenna
12:
11:
5:
5759:
5749:
5748:
5743:
5738:
5721:
5720:
5718:
5717:
5707:
5697:
5687:
5674:
5671:
5670:
5668:
5667:
5660:
5655:
5650:
5645:
5640:
5639:
5638:
5633:
5625:
5619:
5617:
5613:
5612:
5610:
5609:
5604:
5599:
5594:
5589:
5584:
5579:
5574:
5569:
5564:
5558:
5556:
5550:
5549:
5547:
5546:
5541:
5536:
5531:
5526:
5521:
5516:
5511:
5506:
5501:
5496:
5491:
5486:
5480:
5478:
5472:
5471:
5469:
5468:
5463:
5458:
5453:
5448:
5442:
5440:
5436:
5435:
5433:
5432:
5427:
5422:
5417:
5412:
5407:
5405:Space-division
5401:
5399:
5393:
5392:
5390:
5389:
5384:
5383:
5382:
5377:
5367:
5366:
5365:
5355:
5350:
5344:
5342:
5334:
5333:
5331:
5330:
5329:
5328:
5318:
5317:
5316:
5306:
5301:
5296:
5295:
5294:
5284:
5278:
5276:
5268:
5267:
5265:
5264:
5259:
5254:
5249:
5244:
5242:Camille Tissot
5239:
5234:
5229:
5224:
5219:
5217:Claude Shannon
5214:
5209:
5207:Tivadar Puskás
5204:
5199:
5194:
5189:
5184:
5179:
5177:Antonio Meucci
5174:
5169:
5164:
5159:
5154:
5149:
5147:Charles K. Kao
5144:
5139:
5134:
5129:
5124:
5122:Harold Hopkins
5119:
5114:
5109:
5104:
5099:
5094:
5089:
5084:
5079:
5074:
5069:
5064:
5059:
5054:
5049:
5044:
5039:
5034:
5029:
5024:
5022:Emile Berliner
5019:
5014:
5009:
5004:
4999:
4994:
4989:
4983:
4981:
4977:
4976:
4974:
4973:
4968:
4963:
4961:Videotelephony
4958:
4953:
4952:
4951:
4946:
4936:
4929:
4924:
4918:
4913:
4908:
4903:
4898:
4897:
4896:
4891:
4886:
4876:
4875:
4874:
4864:
4859:
4857:Radiotelephone
4854:
4849:
4844:
4839:
4834:
4829:
4824:
4823:
4822:
4812:
4807:
4802:
4797:
4792:
4787:
4782:
4777:
4772:
4767:
4762:
4761:
4760:
4755:
4750:
4745:
4743:Internet video
4735:
4734:
4733:
4728:
4723:
4718:
4708:
4703:
4698:
4693:
4688:
4683:
4677:
4675:
4669:
4668:
4661:
4660:
4653:
4646:
4638:
4629:
4628:
4626:
4625:
4613:
4600:
4597:
4596:
4594:
4593:
4588:
4582:
4580:
4576:
4575:
4573:
4572:
4567:
4561:
4559:
4555:
4554:
4552:
4551:
4546:
4541:
4536:
4531:
4526:
4521:
4516:
4510:
4508:
4504:
4503:
4501:
4500:
4495:
4490:
4485:
4480:
4475:
4470:
4465:
4460:
4455:
4450:
4445:
4440:
4435:
4430:
4425:
4420:
4415:
4410:
4404:
4402:
4398:
4397:
4395:
4394:
4389:
4384:
4379:
4374:
4369:
4364:
4358:
4356:
4352:
4351:
4349:
4348:
4343:
4338:
4333:
4328:
4323:
4318:
4312:
4310:
4300:
4299:
4297:
4296:
4291:
4286:
4281:
4276:
4271:
4264:Satellite dish
4261:
4256:
4251:
4246:
4241:
4236:
4231:
4225:
4223:
4219:
4218:
4216:
4215:
4210:
4205:
4200:
4195:
4193:Ground station
4190:
4185:
4180:
4175:
4169:
4167:
4163:
4162:
4155:
4154:
4147:
4140:
4132:
4123:
4122:
4120:
4119:
4114:
4109:
4107:Spiral antenna
4104:
4099:
4094:
4089:
4084:
4079:
4073:
4067:
4065:
4061:
4060:
4058:
4057:
4052:
4047:
4042:
4040:Sterba antenna
4037:
4032:
4027:
4025:Sector antenna
4022:
4017:
4012:
4007:
4002:
4000:Plasma antenna
3997:
3992:
3987:
3982:
3977:
3972:
3967:
3962:
3957:
3952:
3947:
3942:
3937:
3932:
3927:
3922:
3917:
3912:
3907:
3902:
3897:
3892:
3887:
3882:
3877:
3875:Adcock antenna
3871:
3869:
3863:
3862:
3860:
3859:
3854:
3849:
3844:
3839:
3834:
3832:Sloper antenna
3829:
3824:
3819:
3814:
3809:
3807:J-pole antenna
3804:
3799:
3794:
3789:
3784:
3779:
3774:
3769:
3764:
3759:
3757:Dipole antenna
3754:
3749:
3744:
3739:
3734:
3729:
3723:
3721:
3715:
3714:
3712:
3711:
3705:
3703:
3697:
3696:
3688:
3687:
3680:
3673:
3665:
3659:
3658:
3653:
3648:
3642:
3636:
3630:
3625:
3620:
3601:
3600:External links
3598:
3596:
3595:
3558:
3533:
3526:
3495:
3478:
3471:
3448:
3441:
3416:
3409:
3389:
3382:
3362:
3328:
3293:
3287:978-0471743682
3286:
3266:
3245:
3224:
3209:
3202:
3171:
3164:
3141:
3134:
3107:
3067:
3061:978-0470576649
3060:
3023:
3002:
2983:
2981:
2978:
2977:
2976:
2966:
2961:
2959:Satellite dish
2954:
2951:
2820:Heinrich Hertz
2786:
2785:
2775:
2768:
2766:
2759:
2752:
2750:
2739:
2732:
2730:
2726:Würzburg-Riese
2724:
2717:
2715:
2704:
2697:
2695:
2692:
2685:
2683:
2680:
2673:
2671:
2668:
2661:
2659:
2656:
2649:
2647:
2644:
2637:
2634:
2633:
2632:
2630:
2627:
2606:
2602:
2599:
2593:
2582:
2578:
2575:
2569:
2564:
2560:
2549:
2536:
2516:
2513:
2510:
2507:
2504:
2482:
2478:
2452:
2448:
2445:
2439:
2436:
2433:
2427:
2424:
2419:
2416:
2410:
2407:
2404:
2399:
2395:
2372:
2369:
2366:
2346:
2343:
2340:
2337:
2334:
2329:
2325:
2302:
2298:
2267:
2263:
2238:
2218:
2198:
2172:
2169:
2166:
2161:
2158:
2155:
2152:
2149:
2146:
2142:
2138:
2135:
2132:
2129:
2124:
2120:
2110:
2107:
2102:
2099:
2093:
2090:
2087:
2084:
2081:
2071:
2058:
2055:
2052:
2049:
2023:
2020:
2017:
2012:
2008:
2004:
2001:
1998:
1995:
1992:
1989:
1986:
1983:
1979:
1971:
1967:
1961:
1957:
1953:
1950:
1945:
1942:
1937:
1933:
1929:
1926:
1904:
1901:
1898:
1895:
1892:
1889:
1886:
1866:
1863:
1860:
1857:
1854:
1851:
1848:
1828:
1824:
1820:
1817:
1814:
1811:
1807:
1803:
1800:
1797:
1775:
1772:
1767:
1763:
1759:
1756:
1753:
1750:
1747:
1744:
1741:
1738:
1735:
1732:
1728:
1724:
1721:
1718:
1715:
1712:
1707:
1702:
1698:
1694:
1691:
1688:
1685:
1682:
1679:
1675:
1667:
1663:
1659:
1654:
1651:
1648:
1645:
1624:electric field
1604:
1588:
1585:
1576:
1575:
1562:
1558:
1549:
1544:
1539:
1535:
1532:
1526:
1521:
1518:
1489:satellite dish
1466:
1465:
1453:
1449:
1445:
1442:
1439:
1436:
1407:
1404:
1367:
1364:
1348:
1347:
1337:
1327:
1321:
1314:Feed spillover
1305:
1262:
1261:
1240:
1236:
1225:
1213:
1203:
1191:
1181:
1169:
1165:
1159:
1155:
1151:
1148:
1145:
1125:
1111:
1110:
1097:
1093:
1087:
1082:
1077:
1073:
1070:
1064:
1059:
1054:
1050:
1042:
1038:
1033:
1030:
1027:
1021:
1018:
980:Main article:
977:
974:
959:
956:
925:satellite dish
884:
881:
831:
828:
827:
826:
814:
785:
764:
731:
730:
729:
728:
701:
700:
699:
698:
697:
696:
685:
684:
673:
672:
664:
661:cheese antenna
652:dipole antenna
643:
642:
641:
598:
595:
588:
581:
580:
576:
569:
568:
564:
557:
556:
552:
545:
544:
540:
533:
532:
531:
525:
524:
523:
522:
507:
500:
499:
495:
488:
487:
483:
476:
475:
471:
464:
463:
462:
456:
455:
454:
453:
370:
367:
351:electric field
294:
291:
287:radio receiver
229:
226:
207:
203:
199:
195:
191:
187:
174:Heinrich Hertz
109:radio spectrum
81:parabolic dish
15:
9:
6:
4:
3:
2:
5758:
5747:
5744:
5742:
5739:
5737:
5734:
5733:
5731:
5716:
5708:
5706:
5698:
5696:
5688:
5686:
5676:
5675:
5672:
5665:
5661:
5659:
5656:
5654:
5651:
5649:
5646:
5644:
5641:
5637:
5634:
5632:
5629:
5628:
5626:
5624:
5621:
5620:
5618:
5614:
5608:
5605:
5603:
5600:
5598:
5595:
5593:
5590:
5588:
5585:
5583:
5580:
5578:
5575:
5573:
5570:
5568:
5565:
5563:
5560:
5559:
5557:
5555:
5551:
5545:
5542:
5540:
5537:
5535:
5532:
5530:
5527:
5525:
5522:
5520:
5517:
5515:
5512:
5510:
5507:
5505:
5502:
5500:
5497:
5495:
5492:
5490:
5487:
5485:
5482:
5481:
5479:
5477:
5473:
5467:
5464:
5462:
5459:
5457:
5454:
5452:
5449:
5447:
5444:
5443:
5441:
5437:
5431:
5430:Code-division
5428:
5426:
5423:
5421:
5418:
5416:
5415:Time-division
5413:
5411:
5408:
5406:
5403:
5402:
5400:
5398:
5394:
5388:
5385:
5381:
5378:
5376:
5373:
5372:
5371:
5368:
5364:
5361:
5360:
5359:
5356:
5354:
5351:
5349:
5346:
5345:
5343:
5341:and switching
5339:
5335:
5327:
5324:
5323:
5322:
5319:
5315:
5312:
5311:
5310:
5307:
5305:
5302:
5300:
5297:
5293:
5292:optical fiber
5290:
5289:
5288:
5285:
5283:
5282:Coaxial cable
5280:
5279:
5277:
5275:
5269:
5263:
5260:
5258:
5255:
5253:
5250:
5248:
5245:
5243:
5240:
5238:
5235:
5233:
5230:
5228:
5225:
5223:
5220:
5218:
5215:
5213:
5210:
5208:
5205:
5203:
5200:
5198:
5197:Radia Perlman
5195:
5193:
5190:
5188:
5185:
5183:
5180:
5178:
5175:
5173:
5170:
5168:
5165:
5163:
5160:
5158:
5155:
5153:
5150:
5148:
5145:
5143:
5140:
5138:
5135:
5133:
5130:
5128:
5125:
5123:
5120:
5118:
5115:
5113:
5110:
5108:
5105:
5103:
5100:
5098:
5095:
5093:
5090:
5088:
5087:Lee de Forest
5085:
5083:
5082:Thomas Edison
5080:
5078:
5075:
5073:
5072:Donald Davies
5070:
5068:
5065:
5063:
5060:
5058:
5057:Claude Chappe
5055:
5053:
5050:
5048:
5045:
5043:
5040:
5038:
5035:
5033:
5030:
5028:
5025:
5023:
5020:
5018:
5015:
5013:
5010:
5008:
5005:
5003:
5000:
4998:
4995:
4993:
4990:
4988:
4985:
4984:
4982:
4978:
4972:
4969:
4967:
4964:
4962:
4959:
4957:
4954:
4950:
4947:
4945:
4942:
4941:
4940:
4937:
4935:
4934:
4930:
4928:
4925:
4922:
4919:
4917:
4914:
4912:
4909:
4907:
4904:
4902:
4901:Smoke signals
4899:
4895:
4892:
4890:
4887:
4885:
4882:
4881:
4880:
4879:Semiconductor
4877:
4873:
4870:
4869:
4868:
4865:
4863:
4860:
4858:
4855:
4853:
4850:
4848:
4845:
4843:
4840:
4838:
4835:
4833:
4830:
4828:
4825:
4821:
4818:
4817:
4816:
4813:
4811:
4808:
4806:
4803:
4801:
4798:
4796:
4793:
4791:
4788:
4786:
4783:
4781:
4778:
4776:
4773:
4771:
4768:
4766:
4763:
4759:
4756:
4754:
4751:
4749:
4746:
4744:
4741:
4740:
4739:
4738:Digital media
4736:
4732:
4729:
4727:
4724:
4722:
4719:
4717:
4714:
4713:
4712:
4709:
4707:
4704:
4702:
4699:
4697:
4694:
4692:
4689:
4687:
4684:
4682:
4679:
4678:
4676:
4674:
4670:
4666:
4659:
4654:
4652:
4647:
4645:
4640:
4639:
4636:
4624:
4623:
4614:
4612:
4611:
4602:
4601:
4598:
4592:
4589:
4587:
4584:
4583:
4581:
4577:
4571:
4568:
4566:
4563:
4562:
4560:
4556:
4550:
4547:
4545:
4542:
4540:
4537:
4535:
4532:
4530:
4527:
4525:
4522:
4520:
4517:
4515:
4512:
4511:
4509:
4505:
4499:
4496:
4494:
4491:
4489:
4486:
4484:
4481:
4479:
4476:
4474:
4471:
4469:
4466:
4464:
4461:
4459:
4456:
4454:
4451:
4449:
4446:
4444:
4441:
4439:
4436:
4434:
4431:
4429:
4426:
4424:
4421:
4419:
4416:
4414:
4411:
4409:
4406:
4405:
4403:
4399:
4393:
4390:
4388:
4385:
4383:
4380:
4378:
4375:
4373:
4370:
4368:
4365:
4363:
4360:
4359:
4357:
4353:
4347:
4344:
4342:
4339:
4337:
4334:
4332:
4329:
4327:
4324:
4322:
4319:
4317:
4314:
4313:
4311:
4309:
4305:
4301:
4295:
4292:
4290:
4287:
4285:
4282:
4280:
4277:
4275:
4272:
4269:
4265:
4262:
4260:
4257:
4255:
4252:
4250:
4247:
4245:
4242:
4240:
4237:
4235:
4234:Monoblock LNB
4232:
4230:
4227:
4226:
4224:
4220:
4214:
4211:
4209:
4206:
4204:
4201:
4199:
4196:
4194:
4191:
4189:
4186:
4184:
4181:
4179:
4176:
4174:
4171:
4170:
4168:
4166:Main articles
4164:
4160:
4153:
4148:
4146:
4141:
4139:
4134:
4133:
4130:
4118:
4115:
4113:
4110:
4108:
4105:
4103:
4100:
4098:
4095:
4093:
4090:
4088:
4087:Ground dipole
4085:
4083:
4080:
4077:
4074:
4072:
4069:
4068:
4066:
4062:
4056:
4053:
4051:
4048:
4046:
4043:
4041:
4038:
4036:
4033:
4031:
4028:
4026:
4023:
4021:
4018:
4016:
4013:
4011:
4008:
4006:
4003:
4001:
3998:
3996:
3993:
3991:
3988:
3986:
3983:
3981:
3980:Patch antenna
3978:
3976:
3973:
3971:
3970:Moxon antenna
3968:
3966:
3963:
3961:
3958:
3956:
3953:
3951:
3948:
3946:
3943:
3941:
3938:
3936:
3933:
3931:
3928:
3926:
3925:Curtain array
3923:
3921:
3918:
3916:
3913:
3911:
3908:
3906:
3903:
3901:
3898:
3896:
3893:
3891:
3888:
3886:
3883:
3881:
3878:
3876:
3873:
3872:
3870:
3868:
3864:
3858:
3855:
3853:
3850:
3848:
3845:
3843:
3840:
3838:
3835:
3833:
3830:
3828:
3825:
3823:
3820:
3818:
3815:
3813:
3812:Mast radiator
3810:
3808:
3805:
3803:
3800:
3798:
3795:
3793:
3790:
3788:
3785:
3783:
3780:
3778:
3775:
3773:
3770:
3768:
3765:
3763:
3760:
3758:
3755:
3753:
3750:
3748:
3745:
3743:
3740:
3738:
3735:
3733:
3730:
3728:
3725:
3724:
3722:
3720:
3716:
3710:
3707:
3706:
3704:
3702:
3698:
3693:
3686:
3681:
3679:
3674:
3672:
3667:
3666:
3663:
3657:
3654:
3652:
3649:
3646:
3643:
3640:
3637:
3635:
3631:
3629:
3626:
3624:
3621:
3619:
3616:
3615:
3614:
3612:
3607:
3584:on 2012-04-25
3580:
3576:
3569:
3562:
3544:
3537:
3529:
3523:
3519:
3518:
3510:
3508:
3506:
3504:
3502:
3500:
3491:
3490:
3482:
3474:
3472:9780072321036
3468:
3464:
3463:
3455:
3453:
3444:
3438:
3434:
3433:
3425:
3423:
3421:
3412:
3406:
3402:
3401:
3393:
3385:
3379:
3375:
3374:
3366:
3358:
3354:
3350:
3346:
3339:
3332:
3324:
3320:
3316:
3312:
3308:
3304:
3297:
3289:
3283:
3279:
3278:
3270:
3262:
3256:
3248:
3242:
3238:
3231:
3229:
3221:
3220:
3213:
3205:
3199:
3195:
3194:
3186:
3184:
3182:
3180:
3178:
3176:
3167:
3165:9780071639590
3161:
3154:
3153:
3145:
3137:
3135:9788131701843
3131:
3127:
3126:
3118:
3116:
3114:
3112:
3095:
3094:Antenna Types
3091:
3084:
3082:
3080:
3078:
3076:
3074:
3072:
3063:
3057:
3053:
3052:
3044:
3042:
3040:
3038:
3036:
3034:
3032:
3030:
3028:
3019:
3013:
3005:
2999:
2995:
2988:
2984:
2974:
2970:
2967:
2965:
2962:
2960:
2957:
2956:
2950:
2948:
2944:
2940:
2936:
2932:
2928:
2924:
2920:
2916:
2912:
2908:
2904:
2899:
2897:
2893:
2889:
2884:
2879:
2877:
2873:
2869:
2865:
2861:
2857:
2853:
2849:
2844:
2842:
2838:
2834:
2830:
2826:
2821:
2816:
2814:
2810:
2806:
2802:
2798:
2794:
2782:
2778:
2772:
2767:
2763:
2756:
2751:
2747:
2743:
2736:
2731:
2727:
2721:
2716:
2712:
2708:
2701:
2696:
2689:
2684:
2677:
2672:
2665:
2660:
2653:
2648:
2641:
2636:
2635:
2625:
2604:
2600:
2597:
2591:
2580:
2576:
2573:
2567:
2562:
2558:
2548:
2534:
2511:
2505:
2502:
2480:
2476:
2466:
2450:
2446:
2443:
2437:
2434:
2431:
2425:
2422:
2417:
2414:
2408:
2405:
2402:
2397:
2393:
2384:
2370:
2367:
2364:
2344:
2341:
2335:
2327:
2323:
2300:
2296:
2287:
2283:
2265:
2261:
2252:
2236:
2216:
2196:
2186:
2170:
2167:
2164:
2156:
2153:
2150:
2144:
2140:
2136:
2133:
2122:
2118:
2108:
2105:
2100:
2097:
2091:
2085:
2079:
2070:
2053:
2047:
2039:
2034:
2021:
2018:
2015:
2010:
2006:
2002:
1999:
1996:
1993:
1990:
1987:
1984:
1981:
1977:
1969:
1965:
1959:
1955:
1951:
1948:
1943:
1940:
1935:
1931:
1927:
1924:
1916:
1902:
1899:
1896:
1893:
1890:
1887:
1884:
1864:
1861:
1858:
1855:
1852:
1849:
1846:
1826:
1822:
1818:
1815:
1812:
1809:
1805:
1801:
1798:
1795:
1786:
1773:
1770:
1765:
1761:
1754:
1751:
1748:
1745:
1742:
1736:
1733:
1730:
1726:
1722:
1719:
1716:
1713:
1710:
1700:
1696:
1692:
1689:
1686:
1683:
1677:
1673:
1665:
1661:
1657:
1652:
1649:
1646:
1643:
1635:
1633:
1629:
1625:
1621:
1616:
1602:
1594:
1580:
1560:
1556:
1547:
1542:
1537:
1533:
1530:
1524:
1519:
1516:
1509:
1508:
1507:
1504:
1502:
1498:
1494:
1491:operating on
1490:
1485:
1483:
1479:
1475:
1471:
1451:
1447:
1443:
1440:
1437:
1434:
1427:
1426:
1425:
1424:is given by:
1423:
1419:
1415:
1414:
1403:
1401:
1397:
1393:
1389:
1380:
1376:
1372:
1363:
1361:
1357:
1353:
1345:
1341:
1338:
1335:
1331:
1328:
1325:
1322:
1319:
1315:
1312:
1311:
1310:
1304:
1301:
1297:
1295:
1291:
1287:
1283:
1279:
1275:
1271:
1267:
1259:
1257:
1238:
1234:
1226:
1211:
1204:
1189:
1182:
1167:
1163:
1157:
1153:
1149:
1146:
1143:
1123:
1116:
1115:
1114:
1095:
1091:
1085:
1080:
1075:
1071:
1068:
1062:
1057:
1052:
1048:
1040:
1036:
1031:
1028:
1025:
1019:
1016:
1009:
1008:
1007:
1005:
1001:
993:
988:
983:
973:
971:
966:
955:
953:
949:
945:
941:
937:
932:
930:
926:
922:
918:
914:
910:
906:
901:
899:
895:
890:
880:
878:
873:
869:
865:
861:
857:
853:
849:
841:
836:
824:
820:
819:
815:
812:
809:antennas and
808:
804:
799:
798:hyperboloidal
795:
792: – In a
791:
790:
786:
782:
778:
777:
776:
770:
769:
765:
761:
757:
756:
751:
750:
745:
744:
740:
739:
738:
736:
726:
722:
721:
717:
716:
715:
714:
710:
705:
694:
693:
689:
688:
687:
686:
682:
681:
677:
676:
675:
674:
670:
669:
665:
662:
658:
653:
649:
648:
644:
639:
635:
634:
633:Shrouded dish
630:
629:
627:
623:
622:
617:
616:
612:
611:
610:
603:
585:
573:
561:
549:
537:
528:
515:
511:
504:
492:
480:
468:
459:
452:
450:
447:(i.e. a wide
446:
442:
437:
435:
431:
430:coaxial cable
427:
423:
419:
414:
412:
408:
405:
404:coaxial cable
401:
397:
392:
388:
384:
380:
376:
366:
362:
360:
356:
352:
348:
344:
339:
337:
333:
329:
325:
316:
312:
308:
304:
299:
290:
288:
284:
280:
277:cable to the
276:
272:
268:
265:
261:
257:
254:with a small
253:
248:
246:
243:
239:
235:
222:
218:
214:
210:
182:
178:
175:
170:
168:
164:
160:
156:
151:
149:
145:
141:
137:
133:
129:
124:
122:
118:
114:
110:
106:
102:
98:
94:
90:
86:
82:
78:
74:
70:
66:
62:
58:
54:
46:
42:
38:
34:
30:
26:
21:
5397:Multiplexing
5272:Transmission
5237:Nikola Tesla
5227:Henry Sutton
5182:Samuel Morse
5112:Robert Hooke
5077:Amos Dolbear
5012:John Bardeen
4931:
4911:Telautograph
4815:Mobile phone
4770:Edholm's law
4753:social media
4686:Broadcasting
4621:
4609:
4448:Intersputnik
4372:Dish Network
4267:
4035:Slot antenna
4005:Quad antenna
3994:
3990:Planar array
3985:Phased array
3960:Loop antenna
3950:Horn antenna
3857:Whip antenna
3842:T2FD antenna
3787:Halo antenna
3782:G5RV antenna
3641:from YouTube
3603:
3586:. Retrieved
3579:the original
3574:
3561:
3550:. Retrieved
3536:
3516:
3488:
3481:
3461:
3431:
3399:
3392:
3372:
3365:
3348:
3344:
3331:
3306:
3302:
3296:
3276:
3269:
3236:
3217:
3212:
3192:
3151:
3144:
3124:
3098:. Retrieved
3093:
3050:
2993:
2987:
2942:
2900:
2880:
2845:
2841:World War II
2829:focal length
2817:
2790:
2612:(in degrees)
2588:(in radians)
2550:
2467:
2385:
2188:
2072:
2035:
1917:
1787:
1636:
1617:
1590:
1505:
1486:
1481:
1477:
1476:in degrees,
1473:
1469:
1467:
1421:
1411:
1409:
1385:
1378:
1355:
1349:
1340:Shape errors
1339:
1333:
1329:
1323:
1318:feed antenna
1313:
1302:
1298:
1265:
1263:
1254:
1112:
997:
982:Antenna gain
964:
961:
943:
933:
923:. In a home
908:
902:
889:polarization
886:
883:Polarization
872:interference
863:
855:
852:feed antenna
845:
830:Feed pattern
817:
816:
788:
787:
773:
772:
767:
766:
760:feed antenna
754:
753:
748:
747:
742:
741:
732:
719:
718:
691:
690:
679:
678:
667:
666:
660:
656:
646:
645:
632:
631:
620:
619:
615:Paraboloidal
614:
613:
608:
526:
457:
438:
422:RF front end
415:
396:transmitting
383:horn antenna
372:
369:Feed antenna
363:
340:
320:
317:microwaves.
279:feed antenna
256:feed antenna
249:
231:
220:
216:
212:
185:
171:
152:
125:
80:
77:dish antenna
76:
59:that uses a
52:
50:
28:
5597:NPL network
5309:Radio waves
5247:Alfred Vail
5157:Hedy Lamarr
5142:Dawon Kahng
5102:Elisha Gray
5062:Yogen Dalal
4987:Nasir Ahmed
4921:Teleprinter
4785:Heliographs
4458:SED Systems
4392:1worldspace
4208:Transponder
3885:AWX antenna
3867:Directional
3737:Cage aerial
3100:4 September
2872:Grote Reber
2852:short waves
2848:World War I
2833:radio waves
2813:astronomers
2711:Grote Reber
2315:. The term
1396:diffraction
1334:offset feed
823:ellipsoidal
775:offset feed
749:prime focus
647:Cylindrical
445:frequencies
441:nonresonant
271:transmitter
234:focal point
89:searchlight
85:directivity
69:radio waves
27:antenna at
5730:Categories
5643:Antarctica
5602:Toasternet
5524:Television
5007:Paul Baran
4939:Television
4923:(teletype)
4916:Telegraphy
4894:transistor
4872:Phryctoria
4842:Photophone
4820:Smartphone
4810:Mass media
4423:Globalstar
3588:2011-12-24
3552:2009-07-31
3222:, p. 61-62
2980:References
2801:Cassegrain
2705:The first
2036:and using
1593:paraboloid
1288:above the
1270:wavelength
905:orthogonal
789:Cassegrain
755:front feed
626:paraboloid
391:Cassegrain
324:wavelength
260:paraboloid
245:plane wave
242:collimated
238:conductive
105:wavelength
101:beamwidths
93:flashlight
45:Cassegrain
5627:Americas
5616:Locations
5587:Internet2
5348:Bandwidth
5052:Vint Cerf
4949:streaming
4927:Telephone
4867:Semaphore
4758:streaming
4229:SAT>IP
4078:(passive)
3940:Gizmotchy
3847:T-antenna
3701:Isotropic
3351:: 74–84.
3255:cite book
3012:cite book
2973:spherical
2907:Goonhilly
2805:Gregorian
2744:built at
2601:λ
2577:λ
2568:≈
2559:θ
2506:
2477:θ
2447:λ
2438:
2423:π
2418:λ
2409:
2394:θ
2357:whenever
2297:θ
2237:θ
2217:λ
2171:θ
2168:
2157:θ
2154:
2145:λ
2134:π
2106:π
2101:λ
2086:θ
2054:θ
2022:ρ
2016:ρ
2011:λ
2000:θ
1997:
1991:ρ
1985:π
1966:ρ
1956:∫
1952:θ
1944:π
1932:∫
1903:θ
1900:
1894:⋅
1891:ρ
1865:θ
1862:
1856:⋅
1853:ρ
1827:λ
1819:π
1802:ω
1796:β
1766:λ
1734:π
1723:∫
1720:∫
1693:β
1690:−
1684:ω
1653:∫
1650:∫
1538:θ
1531:π
1501:boresight
1444:λ
1435:θ
1406:Beamwidth
1392:sidelobes
1388:main lobe
1290:isotropic
1212:λ
1150:π
1076:λ
1069:π
1037:λ
1029:π
970:sidelobes
936:crosstalk
929:feed horn
868:backlobes
864:spillover
818:Gregorian
803:front end
638:sidelobes
449:bandwidth
418:waveguide
411:waveguide
400:receiving
387:feed horn
385:called a
359:feed horn
307:frequency
159:airplanes
117:microwave
5695:Category
5582:Internet
5572:CYCLADES
5489:Ethernet
5439:Concepts
5363:terminal
5314:wireless
5137:Bob Kahn
4980:Pioneers
4805:Internet
4696:Cable TV
4610:Category
4478:Starlink
4473:Star One
4443:Intelsat
4438:Inmarsat
4428:Hispasat
4418:Eutelsat
4413:EchoStar
4289:Spacebus
4222:Hardware
4097:Rectenna
3895:Cantenna
2969:Simulsat
2953:See also
2911:Cornwall
2383:. Thus,
1400:backlobe
1286:decibels
768:Off-axis
375:low-gain
332:in phase
65:parabola
5715:Commons
5705:Outline
5658:Oceania
5577:FidoNet
5562:ARPANET
5375:circuit
4944:digital
4673:History
4622:Commons
4493:Turksat
4483:Telesat
4453:Iridium
4387:Allente
4367:DirecTV
4341:ISDB-S3
4336:DVB-S2X
4326:DVB-RCS
3692:Antenna
3353:Bibcode
3311:Bibcode
2929:. The
2915:Telstar
2629:History
2280:is the
2251:radians
1497:Arecibo
1113:where:
950:(XPIC)
850:of the
763:55–60%.
285:to the
269:from a
267:current
57:antenna
41:Germany
37:Bavaria
5653:Europe
5623:Africa
5607:Usenet
5567:BITNET
5504:Mobile
5380:packet
4889:MOSFET
4884:device
4681:Beacon
4539:SpaceX
4519:Boeing
4514:Airbus
4498:Viasat
4488:Tooway
4433:Hughes
4382:Sky UK
4331:DVB-S2
4316:DVB-SH
4239:DiSEqC
4071:ALLISS
3524:
3469:
3439:
3407:
3380:
3284:
3243:
3200:
3162:
3132:
3058:
3000:
2939:X-band
2925:, and
2846:After
2825:dipole
2793:optics
2503:arcsin
2435:arcsin
2406:arcsin
2189:where
1788:where
1553:
1493:C band
1468:where
784:below.
311:dipole
228:Design
161:, and
111:, at
55:is an
5636:South
5631:North
5592:JANET
5529:Telex
5519:Radio
5358:Nodes
5353:Links
5274:media
4852:Radio
4837:Pager
4765:Drums
4731:video
4726:image
4716:audio
4579:Lists
4524:INVAP
4321:S-DMB
4244:USALS
4050:WokFi
3694:types
3582:(PDF)
3571:(PDF)
3546:(PDF)
3341:(PDF)
3156:(PDF)
2883:radar
2850:when
2286:nulls
1382:see).
1379:(top)
1360:ITU-R
917:right
752:, or
743:Axial
597:Types
355:radar
336:truss
155:radar
97:gains
5648:Asia
5534:UUCP
5494:ISDN
3522:ISBN
3467:ISBN
3437:ISBN
3405:ISBN
3378:ISBN
3282:ISBN
3261:link
3241:ISBN
3198:ISBN
3160:ISBN
3130:ISBN
3102:2024
3056:ISBN
3018:link
2998:ISBN
2937:and
2923:KDDI
2803:and
2574:1.22
2444:1.22
2415:3.83
2371:3.83
1877:and
1000:gain
990:The
976:Gain
919:and
860:gain
846:The
735:feed
621:dish
512:, a
328:gain
303:MMDS
202:, FP
194:, FP
130:for
115:and
73:dish
5539:WAN
5509:NGN
5499:LAN
4780:Fax
4721:DCT
4544:SSL
4463:SES
3319:doi
2947:NEC
2919:NTT
2909:in
2894:at
2165:sin
2151:sin
1994:cos
1897:sin
1859:cos
771:or
659:or
618:or
409:or
398:or
121:SHF
113:UHF
91:or
79:or
35:),
5732::
4308:TV
4306:/
3573:.
3498:^
3451:^
3419:^
3349:73
3347:.
3343:.
3317:.
3307:12
3305:.
3257:}}
3253:{{
3227:^
3174:^
3110:^
3092:.
3070:^
3026:^
3014:}}
3010:{{
2921:,
2878:.
2598:70
2465:.
2069:,
1634:.
1258:.
877:dB
746:,
413:.
289:.
221:VF
186:FP
150:.
51:A
39:,
5666:)
5662:(
4657:e
4650:t
4643:v
4270:)
4266:(
4151:e
4144:t
4137:v
3684:e
3677:t
3670:v
3591:.
3555:.
3530:.
3492:.
3475:.
3445:.
3413:.
3386:.
3359:.
3355::
3325:.
3321::
3313::
3290:.
3263:)
3249:.
3206:.
3168:.
3138:.
3104:.
3064:.
3020:)
3006:.
2935:S
2605:D
2592:=
2581:D
2563:0
2535:x
2515:)
2512:x
2509:(
2481:0
2451:D
2432:=
2426:D
2403:=
2398:0
2368:=
2365:x
2345:0
2342:=
2339:)
2336:x
2333:(
2328:1
2324:J
2301:0
2266:1
2262:J
2197:D
2160:]
2148:)
2141:/
2137:D
2131:(
2128:[
2123:1
2119:J
2109:D
2098:2
2092:=
2089:)
2083:(
2080:E
2057:)
2051:(
2048:E
2019:d
2007:/
2003:l
1988:i
1982:2
1978:e
1970:0
1960:0
1949:d
1941:2
1936:0
1928:=
1925:E
1888:=
1885:y
1850:=
1847:x
1823:/
1816:2
1813:=
1810:c
1806:/
1799:=
1774:S
1771:d
1762:/
1758:)
1755:y
1752:m
1749:+
1746:x
1743:l
1740:(
1737:i
1731:2
1727:e
1717:=
1714:S
1711:d
1706:)
1701:1
1697:r
1687:t
1681:(
1678:j
1674:e
1666:1
1662:r
1658:A
1647:=
1644:E
1603:D
1561:A
1557:e
1548:2
1543:)
1534:k
1525:(
1520:=
1517:G
1482:k
1478:k
1474:θ
1470:k
1452:d
1448:/
1441:k
1438:=
1422:θ
1346:.
1306:A
1303:e
1239:A
1235:e
1190:d
1168:4
1164:/
1158:2
1154:d
1147:=
1144:A
1124:A
1096:A
1092:e
1086:2
1081:)
1072:d
1063:(
1058:=
1053:A
1049:e
1041:2
1032:A
1026:4
1020:=
1017:G
801:"
663:.
223:.
217:L
213:F
208:3
206:Q
204:3
200:2
198:Q
196:2
192:1
190:Q
188:1
119:(
31:(
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