Microstrip Antennas: Overview of Types, Shapes, and Substrates
Microstrip Antenna
Supervised by :
Dr. Sherif HEKAL
Presented by:
Eng. Ramez hosny
eng. fady emad
u
n
i
v
e
r
s
i
t
y
1
/
2
2
10/3/2024
10/3/2024
10/3/2024
10/3/2024
10/3/2024
10/3/2024
10/3/2024
10/3/2024
10/3/2024
M
i
c
r
o
-
S
t
r
i
p
A
n
t
e
n
n
a
s
Outlines
:
Introduction
.
Micro
s
trip Antennas
Types
.
Micro
s
trip Antennas Shapes
.
Types
of
Substrates
(Dielectric
Media
)
.
Comparison of
various
types of
flat profile printed antennas
.
Advantages
&
DisAdvantages
of
MSAs
.
Applications of
MSAs
.
Radiation
patterns
of
MSAs
.
How
to
Optimizing
the
Substrate Properties
for
Increased Bandwidth
?
Comparing
the
different feed
techniques
.
Design Of Microstrip
•
I
n
t
r
o
d
u
c
t
i
o
n
In
its most basic
form,
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
For
good
antenna performance,
a
thick dielectric
substrate
having
a
low
dielectric
constant
is
desirable
since
this
provides
better
efficiency,
larger
bandwidth
and
better
radiation
.
In
ge
n
ar
a
l
M
i
c
ro
strip
an
t
en
n
as
are
a
l
so
known
as
“
PATCH ANTENNAS
”.
These
are
mostly
used at
microwave
frequencies.
Because the
size
of the antenna
is
directly
t
i
e
d
the
w
av
e
l
e
n
g
th
a
t
the
resona
n
t
frequency.
Micro strip
patch
antenna
or
patch antenna
is
a
narrowband
width
antenna
.
Structure
of a
Microstrip
Patch
Antenna
Micro strip antennas are
easy
to
fabricate
and comfortable
on curved
surface
.
The directivity
is
fairly insensitive
to
the substrate
thickness.
Micro
strip patch antennas patches are
in
variety of shapes
,
such
as
rectangular , square , triangular and
circulator
…etc.
P
a
t
c
h
a
n
t
e
n
n
a
a
)
S
i
n
g
l
e
r
a
d
i
a
t
i
n
g
p
a
t
c
h
e
s
b
)
S
i
n
g
l
e
s
l
o
t
r
a
d
i
a
t
o
r
•
Microstrip Antennas Shapes
Substrates
are:
The
most commonly
used
substrates
are,
1)
Honey comb(dielectric
constant=1.07)
2)Duroid(dielectric
constant=2.32)
3)Quartz(dielectric
constant=3.8)
4)Alumina(dielectric
constant=10
)
A
thicker
substrate
will
increase
the
radiation
power
,
reduce
conductor
loss
and
improve
Band
width
.
•
Types
of
Substrates
(Dielectric
Media)
•
Comparison
of
various
types of
flat profile
antennas:
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.
Disadvantages
Narrow
bandwidth
associated
with
tolerence
problem
Lower
Gain(Nearly
6db
(
.
Spurious
feed
radiation (surface
waves, Feed
strips,
etc.)
Most
microstrip
antennas
radiate
into
half-space
.
Relatively low
efficiency (due
to
dielectric
and
conductor
losses
)
.
low impedance
bandwidth.
Extraneous radiation
from feeds
and junctions
.
Low
power
handling
capacity.
•
Solution :
Low
power
and
low
gain
can
overcome
by
arrays
configuration
.
Surface
wave
associated
limitations
such as
poor
efficiency
,increased
mutual
coupling
,
reduced
gain
and
radiation
pattern
can
overcome.
The
band
width
can
increase
up
to
60%
by
using
some special
techniques
.
Applications
Used
in
mobile
satellite
communication
system.
Direct
broad
cast
television
(
DBS
).
Wire
less
LAN’S.
Feed
elements
in
coaxial
system
GPS
system.
Missiles and
telementry
UHF
Patch
Antennas
for
Space
U
H
F
P
a
t
c
h
a
n
t
e
n
n
a
UHF
Patch
Antennas for
Space
Antenna
Development
Corporation,
Inc.(AntDevCo) employees
have
designed
and
manufactured spacecraft microstrip
patch
antennas
for
many
small
spacecraft
programs
.
These
antennas are
capable of
supporting high
data
rates
to
at
least
10
Watts
of
transmitted
power.
Applications include
GPS,
NASA
SN
(Including
TDRSS
forward/return
pairs),
radar
transponder,
The
antennas can
be supplied with
LHCP, RHCP,
or
linear
polarization
.
•
Some Of Application:
•
Why we
use
Microstrip
Patch
Antennas
?
Used
for
some
reasons:
Flat surface
makes
them ideal
for
mounting
on
airplane
Impedance
matching fairly
simple
Microstrip patch antennas
have
a
very high
antenna
quality
factor(Q
)
.
Radiation
patterns
of a
rectangular microstrip
patch
antenna
T
h
e
d
i
r
e
c
t
i
v
i
t
y
o
f
a
m
i
c
r
o
s
t
r
i
p
a
n
t
e
n
n
a
a
s
a
f
u
n
c
t
i
o
n
o
f
d
i
e
l
e
c
t
r
i
c
c
o
n
s
t
a
n
t
c
o
m
p
u
t
e
d
:
-
•
Radiation
patterns
of
MSAs
.
Figure shows
that
:A
microstrip
patch
that uses
a
thicker substrate
is
more
efficient
.
In
addition,
as the
substrate
thickness increases,
the
radiation
Q
of
the
antenna
decreases.
Thus, impedance bandwidth
increases
with
increasing
substrate
thickness.
Radiation
efficiency,
h, and
unloaded
radiation
Q,
Q
o,
as a
function
of
substrate
thickness
.
•
O
p
t
i
m
i
z
i
n
g
t
h
e
S
u
b
s
t
r
a
t
e
P
r
o
p
e
r
t
i
e
s
f
o
r
I
n
c
r
e
a
s
e
d
B
a
n
d
w
i
d
t
h
The easiest
way
to increase
the
bandwidth of
an
MSA is
to
:
1
)
the
antenna
on a
thicker
substrate
.
2
)
Decrease
the
dielectric
constant
of the
substrate.
3
)
Stack two
patches
on
top
of each other
separated
by
a
dielectric
substrate
or
spacers.
A
s
t
a
c
k
e
d
c
i
r
c
u
l
a
r
p
a
t
c
h
E
M
C
-
M
S
A
f
e
d
u
s
i
n
g
a
c
o
a
x
i
a
l
p
r
o
b
e
.
•
Comparing
the
different
feed
techniques
:-
•
Feeding
Techniques:
Coaxial
feed
Microstrip
feed
Proximity
coupled
microstrip
feed
Aperture coupled
microstrip
feed
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
.
P
r
o
b
e
f
e
d
R
e
c
t
a
n
g
u
l
a
r
M
i
c
r
o
s
t
r
i
p
P
a
t
c
h
A
n
t
e
n
n
a
f
r
o
m
t
o
p
-
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.
T
h
i
s
f
e
e
d
m
e
t
h
o
d
i
s
e
a
s
y
t
o
f
a
b
r
i
c
a
t
e
a
n
d
h
a
s
l
o
w
s
p
u
r
i
o
u
s
r
a
d
i
a
t
i
o
n
.
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
side
view
3-
-
Aperture Coupled
Feed
In
this
type
of
feed
technique,
the
radiating patch
and the
microstrip
feed
line
are
separated
by
the
ground
plane
.
Coupling between
the
patch
and the
feed
line
is made
through
a
slot or an
aperture
in
the
ground
plane.
A
p
e
r
t
u
r
e
-
c
o
u
p
l
e
d
f
e
e
d
The
coupling aperture
is usually
centered
under
the
patch
,
leading
to lower cross polarization
due
to symmetry
of
the
configuration.
The amount of
coupling from
the
feed
line
to
the
patch
is determined by
the
shape,
size
and
location
of the
aperture.
4-
-
Proximity
Coupled
Feed
This
type
of
feed
technique is also
called
as
“
the
electromagnetic coupling scheme
”
.
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
.
Design Of Microstrip :
W
h
e
r
e
:
Design Of Microstrip :
Design Of Microstrip :
Design Of Microstrip :
T
h
e
l
e
n
g
t
h
“
L
“
:
This article delves into the world of Microstrip Antennas, exploring various types, shapes, and substrates used. It covers the advantages, applications, and radiation patterns of Microstrip Antennas, as well as insights on optimizing substrate properties for increased bandwidth and comparing different feed techniques. The content also touches upon the fabrication ease, directivity, and characteristics of Microstrip Patch Antennas.
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Presentation Transcript
university 10/3/2024 Microstrip Antenna Supervised by : Dr. Sherif HEKAL Presented by: Eng. Ramez hosny 1/22 eng. fady emad
Micro-StripAntennas Outlines : Introduction . Microstrip Antennas Types . Microstrip Antennas Shapes . Types of Substrates(Dielectric Media). Comparison of various types of flat profile printed antennas . Advantages & DisAdvantages Applications of MSAs . Radiation patterns of MSAs . How to Optimizing the Substrate Properties for Increased Bandwidth ? Comparing the different feed techniques . Design Of Microstrip of MSAs .
Introduction In its most basic form, 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 For good antenna performance, a thick dielectric substrate having a low dielectric constant is desirable since this provides better efficiency, larger bandwidth and better radiation . In genaral Micro strip antennas are also known as PATCH ANTENNAS . These are mostly used at microwave frequencies. Because the size of the antenna is directly tied the wavelength frequency. Micro strip patch antenna or patch antenna is a narrowband width antenna. at the resonant Structure of a Microstrip PatchAntenna
Micro strip antennas are easy to fabricate and comfortable on curved surface. The directivity is fairly insensitive to the substratethickness. Micro strip patch antennas patches are in variety of shapes, such as rectangular , square , triangular and circulator etc. Patch antenna
Microstrip Antennas Shapes a) Single radiatingpatches b) Single slotradiator
Types of Substrates(Dielectric Media) Substratesare: The most commonly used substratesare, 1)Honey comb(dielectric constant=1.07) 2)Duroid(dielectric constant=2.32) 3)Quartz(dielectric constant=3.8) 4)Alumina(dielectricconstant=10) A thicker substrate will increase the radiationpower , reduce conductor loss and improve Bandwidth.
Comparisonof various types of flat profile antennas: Charaterstics Microstrippatch antenna Microstripslot antenna Profile Thin Thin Fabrication Very easy Easy Polarization Both linear& circular Both linear& circular Dual freq operation Possible Possible Shape Any shape Rec &circle
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.
Disadvantages Narrow bandwidth associated with tolerence problem Lower Gain(Nearly 6db( . Spurious feed radiation (surface waves, Feed strips, etc.) Most microstrip antennas radiate into half-space . Relatively low efficiency (due to dielectric and conductor losses) . low impedance bandwidth. Extraneous radiation from feeds and junctions . Low power handling capacity.
Solution : Low power and low gain can overcome by arraysconfiguration. Surface wave associated limitations such as poor efficiency,increased mutual coupling , reduced gain and radiation pattern can overcome. The band width can increase up to 60% by using some special techniques.
Applications Used in mobile satellite communication system. Direct broad cast television (DBS). Wire less LAN S. Feed elements in coaxial system GPS system. Missiles and telementry UHF Patch Antennas for Space
Some Of Application: UHF Patch Antennas for Space Antenna Development Corporation, Inc.(AntDevCo) employees have designed and manufactured spacecraft microstrip patch antennas for many small spacecraft programs. These antennas are capable of supporting high data rates to at least 10 Watts of transmitted power. Applications include GPS, NASA SN (Including TDRSS forward/return pairs), radar transponder, The antennas can be supplied with LHCP, RHCP, or linear polarization . UHF Patchantenna
Why we use Microstrip Patch Antennas? Used for some reasons: Flat surface makes them ideal for mounting on airplane Impedance matching fairly simple Microstrip patch antennas have a very high antenna quality factor(Q).
Radiation patterns of MSAs . Radiation patterns of a rectangular microstrip patchantenna The directivity of a microstrip antenna as a function of dielectric constant computed:-
Radiation efficiency, h, and unloaded radiation Q, Q o, as a function of substrate thickness . Figure shows that :A microstrip patch that uses a thicker substrate is more efficient. In addition, as the substrate thickness increases, the radiation Q of the antenna decreases. Thus, impedance bandwidth increases with increasing substrate thickness.
Optimizing the Substrate Properties for Increased Bandwidth The easiest way to increase the bandwidth of an MSA is to : 1) Print the antenna on a thickersubstrate. 2) Decrease the dielectric constant of thesubstrate. 3) Stack two patches on top of each other separated by a dielectric substrate orspacers. A stacked circular patch EMC-MSA fed usinga coaxialprobe.
Comparing the different feed techniques:-
FeedingTechniques: Coaxial feed Microstrip feed Proximity coupled microstrip feed Aperture coupled microstrip feed 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 sideview
3--Aperture CoupledFeed In this type of feed technique, the radiating patch and the microstrip feed line are separated by the ground plane. Coupling between the patch and the feed line is made through a slot or an aperture in the ground plane. Aperture-coupledfeed The coupling aperture is usually centered under the patch, leading to lower cross polarization due to symmetry of the configuration. The amount of coupling from the feed line to the patch is determined by the shape, size and location of theaperture.
4--Proximity CoupledFeed This type of feed technique is also called as the electromagnetic coupling scheme . Proximity-coupledFeed 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 properalignment. Also, there is an increase in the overall thickness of the antenna.
Design Of Microstrip : Where :
Design Of Microstrip : The length L :
