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Parabolic antenna
This document defines and describes parabolic antennas. It discusses the key components of a parabolic antenna including the focus, vertex, focal length, and aperture. It then explains how parabolic and hyperbolic reflectors work to direct radio waves. The document outlines different types of parabolic antennas and their applications. Parabolic antennas are commonly used for point-to-point communication, microwave relay links, wireless networks, satellite communication, radio telescopes, and radar due to their high directivity and gain.
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Parabolic antenna
- 1. Presented to :Sir Eng. LATIF JAN Presented by : NIK JAMAL ID: 5370
- 3. Definition Terminologies Basic Antenna Types Types of shapes Radiation Pattern Concept Features Applications
- 4. A parabolicantenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of arabola, to direct the radio waves. It is often referred to as a dish antenna.
- 5. Focus-The focusis where all the incoming radio waves are concentrated. Vertex-The vertex is the innermost point at the center of the parabolic reflector. Focal length-The focal length of a parabola is the distance from its focus to its vertex. Aperture-The aperture of a parabolic reflector is its opening and is described by its diameter.
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- 7. A parabolic reflector addsall the fields from a surface = aperture at a focal point
- 8. . A Light from thepoint A . B appears to come from point B reflecting off the hyperbola
- 9. Hyperbolic reflector: B Light convergingtowards B A converges at A reflecting off the hyperbola
- 10. Parabolic reflector Hyperbolic reflector Parabolic primary &Hyperbolic secondary
- 11. AT antenna: •Cassegrain configuration •22-mdiameter primary main reflector •2.75-m secondary reflector
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- 14. Parabolic antennas aredistinguished by their shapes. Paraboloidal or dish Shrouded dish Cylindrical
- 15. The reflector isshaped like a paraboloid. This is the most common type. It radiates a narrow pencil-shaped beam along the axis of the dish.
- 16. The shroud shieldsthe antenna from radiation from angles outside the main beam axis, reducing the side lobes. Shrouded microwave relay dishes on a communications tower in Australia.
- 17. The reflector iscurved in only one direction and flat in the other. The radio waves come to a focus not at a point but along a line.
- 18. Greater Directivityand Gain. Parabolic or dish antennas are NOT frequency dependant. Receives and radiates signals only in one direction. Produce sharp and narrow beamwidth of any antenna types. Handy for end users (small reflector antenna).
- 19. Parabolic antennasare used as High gain antennas for point to point communication In applications such as microwave relay links that carry telephone and television signals between nearby cities Wireless WAN/LAN links for data communications satellite and spacecraft communication antennas Radio telescopes Radar antennas Satellite television dish antennas