Laxmi Institute of Technology, Sarigam
Department of Electronics & Communication
(6 SEM)
Engineering
Presentation
On
Horn, Slot & Patch Antenna
Submitted by:-
Name: EnrollnmentNo.
 JayBaria
 Vikas Choudhary
150860111003
150860111004
Approved byAICTE, New Delhi;Affiliated to Gujarat Technological University,
Ahmedabad
Guided by:- Ms.
Suchita Borkar
HOD (ECE)
LIT, Sarigam.

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.
 Horns are widely used as antennas at UHF and
microwave frequencies, above 300 MHz .
 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.
 Extension of waveguide in form of horn is called Horn Antenna.

Working:-
-A 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.

Radiation Pattern:-

Gain :-
Horns have very little loss, so the directivity of a horn is
roughly equal to its gain. The gain G of a pyramidal horn
antenna (the ratio of the radiated power intensity along its
beam axis to the intensity of an isotropic antenna with the
same input power) is:

To find the directivity, the maximum radiation is formed. That
is,
Umax = U(lj,Ф)|max = r2/2Lj|E|2
max
For most horn antennas |E|max is directed nearly along the z-
axis (lj= 0). Thus,
|E|max = [ |Elj|2
max + |EФ|2
max]1/2
=
Directivity :-

F(t) = [ C(t) - j S(t) ]
Since kx = ky = 0
t1= - t & t2 = t
C(-t) = - C(t)
S(-t) = - S(t)
Directivity :-

Umax = U(lj,Ф)|max = r2/2Lj|E|2
max
=
|F(t)|2 = [ C2( + S2(
The total power radiated can be simply integrating the
average power density over the aperture of the horn.
) )]
Lj
Lj
Directivity :-

Directivity :-

Types of HornAntenna:
• E-plane sectored horn
• H-plane sectored horn
• Pyramidal horn antenna
• Conical horn antenna
• Exponential horn antenna

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Relativepower(dBdown)
E- and H-Plane Patterns of the E-Plane
Sectoral Horn:-
E-Plane
H-Plane
15
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15
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18
00

E- and H-Plane Patterns of the H-Plane
Sectoral Horn:-
E-Plane
H-Plane
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E and H-Plane Patterns :-
E-Plane
H-Plane
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900
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Relativepower(dBdown)

E- and H-Plane Patterns of The Conical
Horn Antenna :-
E-Plane
H-Plane
00
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900
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Relativepower(dBdown)

Advantages of Horn Antenna :-
• They can operate over wide ranges of frequencies.
• Very wide bandwidth, for example allowing it to operate
from 1GHz to 20GHz, 20:1.
• High Directivity.
• High gain.
• Support for wide applications.

Applications :
• They are used as 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.
• Acommon element of phase array.
• Satellite and microwave communications.
• Used in the calibration, other high gain antenna.
• Used for making electromagnetic interference measurement.

Microstrip Patch Antenna :-
• MicrostripAntenna was Invented by Bob Munson in 1972 .
• Microstrip antennas are attractive due to their light weight,
conformability and low cost.
• These antennas can be integrated with printed strip-line feed
networks and active devices. This is a relatively new area of
antenna engineering.
• The radiation properties of micro strip structures have been
known since the mid 1950’s.
• A Microstrip Patch antenna consists of a radiating patch on one
side of a dielectric substrate which has a ground plane on the
other side.
• The patch is generally made of conducting material such as
copper or gold and can take any possible shape.
• The radiating patch and the feed lines are usually photo etched
on the dielectric substrate.

Basic Structure Microstrip patch
Antenna
L= Length of the Micro-strip
Patch Element
W = Width of the Micro-strip
Patch Element
t= Thickness of Patch
h = Height of the Dielectric
Substrate.
Microstrip Rectangular Patch Antenna

Some of the Typical Shapes of Patch
8
Rectangular Square Circular
Elliptical
Circular ring
Triangular

Feeding Techniques:
 Coaxial feed
 Microstrip feed
 Proximity coupled microstrip feed
 Aperture coupled microstrip feed
 Coplanar wave guide
 Line Feed

1-Microstrip Line Feed :
 In this type of feed technique, a conducting strip
is connected directly to the edge of the microstrip
patch.
 This kind of feed arrangement has the advantage
that the feed can be etched on the same substrate to
provide a planar structure.

2-Coaxial Feed :-
The Coaxial feed or probe feed is a very common
technique used for feeding Microstrip
patch antennas.
The main advantage of this type of feeding
scheme is that the feed can be placed at any
desired location inside the patch in order to
match with its input impedance.
This feed method is easy to fabricate and has
low spurious radiation.
However, its major disadvantage is that it
Coaxial Ground Plane Connector Substrate
Patch provides narrow bandwidth and is
difficult to model since a hole has to be drilled
in the substrate . and the connector protrudes
outside the ground plane, thus not making it
completely planar for thick substrates .
Probe fed Rectangular Microstrip Patch
Antenna from top
Probe fed Rectangular Microstrip Patch Antenna from
side view

3-Aperture Coupled Feed
In this type of feed technique, the radiating patch
and the microstrip feed line are separated by the
groundplane .
Coupling between the patch and the feed
line is made through a slot or an aperture in
the ground plane.
The coupling aperture is usually centered under the
patch, leading to lower cross polarization due to symmetry
of the configuration.
Aperture-coupledfeed
The amount of coupling from the feed line to the patch is determined by the shape, size
and location of the aperture.

This type of feed techniƋue is also called as ͞the
electromagnetic coupling scheme͟ .
Proximity-coupled Feed
Two dielectric substrates are used such that the feed line is between the two substrates and
the radiating patch is on top of the upper substrate.
The main advantage of this feed technique is that it eliminates spurious feed radiation and
provides very high bandwidth due to overall increase in the thickness of the microstrip patch
antenna.
This scheme also provides choices between two different dielectric media, one for the patch
and one for the feed line to optimize the individual performances.
Matching can be achieved by controlling the length of the feed line and the width-to-line ratio
of the patch.
The major disadvantage of this feed scheme is that it is difficult to fabricate because of the
two dielectric layers which need proper alignment.
Also, there is an increase in the overall thickness of the antenna.
4-Proximity Coupled
Feed

Comparing the different feed techniques :-

Advantages:
 Low fabrication cost, hence can be manufactured in large
quantities.
 Easily integrated with microwave integrated circuits (MICs).
 Capable of dual and triple frequency operations.
 Supports both, linear as well as circular polarization.
 Low cost , Less size , Low Mass .
 Mechanically robust when mounted on rigid surfaces.
 High Performance
 Light weight and low volume.

Applications:
Used in mobile satellite communication system.
Direct broad cast telivision(DBS).
Wiƌe less LAN’S.
Feed elements in coaxial system
GPS system.
Missiles and telementry
UHF Patch Antennas for Space

Slot Antenna:-
 Slot antennas are used typically at frequencies between 300 MHz and 24
GHz. The slot antenna is popular because they can be cut out of whatever
surface they are to be mounted on, and have radiation patterns that are
roughly omni directional (similar to a linear wire antenna, as we'll see).
 The polarization of the slot antenna is linear. The slot size, shape and
what is behind it (the cavity) offer design variables that can be used to
tune performance.

Slot Antenna Design

Babinet’s Principle
-Relates the radiated fields and impedance of an aperture or slot
antenna to that of the field of its dual antenna.
-The dual of a slot antenna would be if the conductive material
and air were interchanged - that is, the slot antenna became a
metal slab in space.

Complementary Antennas

Babinet's principle relates these two
antennas.
impedance
The first result
of
the
states that the
the slot antenna (Zs) is
related to impedance of its dual
antenna (Zc) by the relation:
In the above,
free space.
is the intrinsic impedance of

Main advantages are :-
1) Its size,
2) Design Simplicity,
3) Robustness,
4) Versitile,
5) Convenient adaptation to mass production using PC board
technology.

Thank you…!!