Parabolic antenna is a single reflector type antenna, which utilizes an axisymmetric rotating paraboloid as the main reflecting surface, and places the feed source at the focal point F of the paraboloid, and the feed source usually adopts a horn antenna or an array of horn antennas. When transmitting, the signal is radiated from the feed source to the paraboloid, and then reflected from the paraboloid and radiated into the air. Since the feed source is located at the focus of the paraboloid, the wave is reflected by the paraboloid and then radiated parallel to the paraboloid normal. When received, the wave is reflected by the reflecting surface and converges to the feed source, which can receive the maximum signal energy.
The main advantage of parabolic antenna is strong directionality. Its function is similar to the reflector of a searchlight or flashlight, which can converge the waves into a narrow beam in a specific direction, or receive waves from a specific direction. Parabolic antennas are the most productive, meaning they produce the narrowest beamwidths regardless of antenna type. In order to achieve a narrow beamwidth, the parabolic reflector must be much larger than the wavelength of the radio wave being used, so parabolic antennas are used in the high-frequency portion of the radio spectrum (UHF and VHF) because the wavelengths are sufficiently small to be reflected through the use of reflective surfaces.
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