Parabolic antenna

Parabolic antenna

1. IQRA NATIONAL UNIVERSITY Presented to : Sir Eng. LATIF JAN Presented by : NIK JAMAL ID: 5370

2. Parabolic Antenna

3. Definition Terminologies Basic Antenna Types Types of shapes Radiation Pattern Concept Features Applications Contents

4. A parabolic antenna 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. Parabolic antenna

5. Focus -The focus is 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. Terminologies

6. Radiation Pattern Concept Antenna Test Range Antenna Under Test Source Antenna

7. Parabolic reflector A parabolic reflector adds all the fields from a surface = aperture at a focal point

8. Hyperbolic reflector . A Light from the point A . B appears to come from point B reflecting off the hyperbola

9. Hyperbolic reflector : Hyperbolic reflector : B Light converging towards B A converges at A reflecting off the hyperbola

10. Parabolic reflector Parabolic reflector Hyperbolic reflector Parabolic primary & Hyperbolic secondary

11. AT antenna: Cassegrain configuration 22-m diameter primary main reflector 2.75-m secondary reflector

12. Signal path

13. Basic Antenna Types Standard Parabolic Antenna Shielded Antenna Focal Plane Antenna GRIDPAK ® Antenna

14. Parabolic antennas are distinguished by their shapes. Paraboloidal or dish Shrouded dish Cylindrical Type of shapes

15. Paraboloidal or dish The reflector is shaped like a paraboloid . This is the most common type. It radiates a narrow pencil-shaped beam along the axis of the dish.

16. Shrouded dish The shroud shields the 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. Cylindrical 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 .

18. Features of Parabolic antenna Greater Directivity and 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. Applications Parabolic antennas are 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

20. Any Question