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.

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 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.

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.

6. Antenna Test Range
Antenna
Under
Test
Source
Antenna

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

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

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

10. Parabolic
reflector
Hyperbolic
reflector
Parabolic primary & Hyperbolic
secondary

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

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

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

15. 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. 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. 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.  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.  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