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A typical larger microwave antenna designed for mid to long range A parabolic satellite antenna for Erdfunkstelle Raisting, based in Raisting, Bavaria, Germany. C band horn-reflector antennas on the roof of a telephone switching center in Seattle, Washington, part of the U.S. AT&T Long Lines microwave relay network.
Feed horn with concentric rings (left) and LNB (right) on a Hughes DirecWay home satellite dish. An LNBF (LNB with integrated feed horn) that has been cut into two.Visible is the scalar horn antenna (the funnel with concentric rings), which couples the microwave beam into a short waveguide (the tube connecting the feed horn to the LNB electronics part of the LNBF).
In point-to-point microwave antennas, a "high performance" antenna usually has a higher front to back ratio than other antennas. For example, an unshrouded 38 GHz microwave dish may have a front to back ratio of 64 dB, while the same size reflector equipped with a shroud would have a front to back ratio of 70 dB.
The microwave signal from the dish is picked up by a feedhorn on the LNB and is fed to a section of waveguide. One or more metal pins, or probes, protrude into the waveguide at right angles to the axis and act as antennas , feeding the signal to a printed circuit board inside the LNB's shielded box for processing.
The first modern horn antenna in 1938 with inventor Wilmer L. Barrow. A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz. [1]
The most widely used high gain antenna at microwave frequencies and above. Consists of a dish-shaped metal parabolic reflector with a feed antenna at the focus. It can have some of the highest gains of any antenna type, up to 60 dBi, but the dish must be large compared to a wavelength.
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Aperture blockage – 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 ...