Parabolic antenna

A parabolic satellite communications antenna at Erdfunkstelle Raisting, the biggest facility for satellite communication in the world, in Raisting, Bavaria, Germany. It has a Cassegrain type feed.

Wire grid-type parabolic antenna used for MMDS data link at a frequency of 2.5-2.7 GHz. It is fed by a vertical dipole under the small aluminum reflector on the boom. It radiates vertically polarized microwaves.

Dish parabolic antennasShrouded microwave relay dishes on a communications tower in Australia.A satellite television dish, an example of an offset fed dish.Cassegrain satellite communication antenna in Sweden.Offset Gregorian antenna used in the Allen Telescope Array, a radio telescope at the University of California at Berkeley, USA.

A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct the radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, that is, they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently-sized reflectors can be used.

单词	Radio dish
释义	Radio dish 英语百科 Parabolic antenna A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct the radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, that is, they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently-sized reflectors can be used.
随便看	High watermark的意思 highwater mark的意思 highwater marking的意思 high water neap的意思 high water neaps的意思 high water neap tide的意思 high water observation的意思 high water of neap tide的意思 high water ordinary neap tide的意思 high water ordinary spring的意思 high water ordinary spring tide的意思 high water period的意思 high water quadrature的意思 high water revetment的意思 high water river bed的意思 high water rock的意思 Highwaters的意思 high water的意思 high water season的意思 high water slack的意思 high water spring的意思 high water springs的意思 high water spring tide的意思 high water stage的意思 high water stand的意思

Radio dish

Parabolic antenna