The document provides an overview of horn antennas, describing their structure, working principles, types, advantages, and disadvantages. Horn antennas are flaring metal waveguides used for directing radio waves, commonly employed in UHF and microwave applications. While they offer benefits like wide bandwidth and high directivity, their limitations include a limited gain and non-directive radiation patterns.

1. Presentation gives by: Sheth Purna K.
EC STUDENT
At VGEC,Chandkheda

2. Overview
 Introduction
 Description
 Working
 Types
 Advantages
 Disadvantages
 Applications

3. What is Horn Antenna?
 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.

4.  Horns are widely used as antennas at UHF and
Microwave frequencies, above 300MHz.
 A Horn antenna is used to transmit radio waves
from a waveguide(a metal pipe used to carry radio
waves) out into space, or collect radio waves into
waveguide for reception.

5. Description
 It typically consists of a short length of rectangular or
cylindrical metal tube (the waveguide), closed at one
end, flaring into an open-ended conical or pyramidal
shaped horn on the other end.
 The radio waves are usually introduced into the
waveguide by a coaxial cable attached to the side,
with the central conductor projecting into the
waveguide to form a quarter-wave monopole
antenna.
 The waves then radiate out the horn end in a narrow
beam.

6. Working
 Horn Antenna converts the electric power into radio
waves and vise versa.
 It is usually used with a radio transmitter or radio
receiver.
 It provides a gradual transition structure to match the
impedance of a tube to the impedance of free space,
enabling the waves from the tube to radiate efficiently
into space.

7. Types
 Horns can have different flare angles as well as
different expansion curves (elliptic, hyperbolic, etc.)
in the E-field and H-field directions.
1. Pyramidal horn (a)
2. Sectoral horn
3. E-plane horn (b)
4. H-plane horn (c)
5. Conical horn (d)
6. Exponential horn (e) etc…

8. Pyramidal horn
 A horn antenna with the horn in the shape of a four-
sided pyramid, with a rectangular cross section. They
are a common type, used with rectangular waveguides,
and radiate linearly polarized radio waves

9. Sectoral horn
 A pyramidal horn with only one pair of sides flared
and the other pair parallel.
 It produces a fan-shaped beam, which is narrow in
the plane of the flared sides, but wide in the plane
of the narrow sides.
 These types are often used
as feed horns for wide search
radar antennas.

10. E-plane horn
 A sectoral horn flared in the direction of the electric
or E-field in the waveguide.

11. H-plane horn
 A sectoral horn flared in the direction of the magnetic
or H-field in the waveguide.

12. Conical horn
 A horn in the shape of a cone, with a circular cross
section. They are used with cylindrical waveguides.

13. Exponential horn
 A horn with curved sides, in which the separation of
the sides increases as an exponential function of
length

14. Advantages
 It is simple in construction.
 They can operate over wide range of frequencies.
 Very wide bandwidth, for example allowing it to
operate from 1GHz to 20GHz
 High Directivity
 High Gain
 Support for wide applications

15. Disadvantages
 Horn antenna radiates energy in spherical wave front
shape, as a result horn antenna does not provide
sharp/directive beam.
 Usually gain of horn antenna is limited to 20dB. This is
due to the fact that in order to increase the gain when
the horn opening is made larger, the length of horn
also becomes excessive.

16. Applications
 In Satellite and Microwave communication
 In TV base station
 A common element of phase array
 They are used as a feeders(called feed horn) for larger
antenna structures such as parabolic antennas, as
directive antennas for such devices as radar guns,
automatic doors openers, microwave radiometer.

17. Thank you