Internati
o
nal
Journal of Ele
c
trical
and Computer
Engineering
(IJE
CE)
V
o
l.
3, N
o
. 4
,
A
ugu
st
2013
, pp
. 45
6
~
46
0
I
S
SN
: 208
8-8
7
0
8
4
56
Jo
urn
a
l
h
o
me
pa
ge
: h
ttp
://iaesjo
u
r
na
l.com/
o
n
lin
e/ind
e
x.ph
p
/
IJECE
Desi
gn and Analysis of
T
r
ipple B
a
nd Koch Fract
a
l Yagi Uda
Antenna
Satyandr
a Sin
g
h
l
o
dhi
1
, P
.
K.
S
i
ng
ha
l
2
, V
.
V. T
h
ak
are
3
Department o
f
Electronics Madh
av Institute of
Technolog
y
and
Scien
c
e Gwalior
(
M
.P.) 474005 In
dia
Email: Saty
andr
a.lodh
i1988@gmail.com
1
, pks_65@
y
a
hoo
.com
2
, Vand
anavt_19
@rediffm
ail
.
co
m
3
Article Info
A
B
STRAC
T
Article histo
r
y:
Received
Mar 31, 2013
Rev
i
sed
May 25
, 20
13
Accepted
Jun 27, 2013
The proposed
an
tenna is Koch
fr
actal
pr
inted Yagi-Uda antenn
a fed b
y
SMA
connector. Th
e radiation ch
ar
acteristics of
the antenna ar
e simulated b
y
CS
T
M
i
crowave S
t
u
d
io and
anal
ys
e
d
with
the
help
of sim
u
lated r
e
sults. T
h
e
antenn
a'
s curren
t
s distribution b
ecome
s more uniform after being fractal,
which is conducive to in
crease the an
tenna’s
radiation directivity
.
Th
e
proposed Koch
fractal Yagi-Ud
a
an
tenn
a reson
a
nce at fr
equen
c
y
of 7
.
81
GHz, 8.54 GHz and 9.42 GHz with gain
of 9.6
7
dB, 10.4 dB and 10.61d
B
respectively
.
Parameter of antenna such
as return loss, input impedance,
sm
ith chart, rad
i
ation pa
ttern is a
n
al
yz
ed for perf
ormance evaluation of Koch
fractal Yagi-Uda antenna.
Keyword:
Yagi-Uda anten
n
a,
Return loss,
Gain,
Direct
ivit
y,
Bandwidth,
S
m
ith Chart
,
CST simulator s
o
ftware.
Copyright ©
201
3 Institut
e
o
f
Ad
vanced
Engin
eer
ing and S
c
i
e
nce.
All rights re
se
rve
d
.
Co
rresp
ond
i
ng
Autho
r
:
Satyan
dr
a Si
n
g
h
lodh
i,
Department o
f
Electronics
Madhav Institute of Techno
log
y
and
Scien
c
e Gwalior (M.P.)
47400
5 India
Em
a
il:
Saty
andr
a.lodh
i1988@gmail.com
1.
INTRODUCTION
Yagi
-U
da a
n
t
e
nna i
s
a
ki
n
d
of
di
rect
i
o
nal
ant
e
n
n
a wi
t
h
s
i
m
p
l
e
st
ruct
ur
e. The
Ya
gi
-U
da ant
e
nna
s
have
bee
n
use
d
n
o
t
o
n
l
y
f
o
r
hom
e TV ap
p
l
i
cat
i
ons b
u
t
al
so f
o
r m
odern
wi
rel
e
ss c
o
m
m
uni
cat
i
ons [
1
-3]
.
A
co
nv
en
tio
n
a
l
Yag
i
-Ud
a
an
ten
n
a
con
s
ists
of driv
en
el
emen
t and
sev
e
ral p
a
rasitic elemen
ts (reflecto
r
s and
directors), ra
di
ates end
fire
beam
s [4-6].T
h
e a
n
tenna'
s ch
aracteristic is b
e
ing
d
i
fficult to
in
teg
r
ate with
com
m
uni
cat
i
on
ci
rcui
t
s
a
nd nar
r
o
w
ban
d
w
i
d
t
h
s have
l
i
m
i
t
ed i
t
s
appl
i
cat
i
on sc
o
p
e wi
t
h
t
h
e ra
pi
d
devel
opm
ent
o
f
co
mm
u
n
i
cat
io
n
s
tech
no
logy. Sev
e
r
a
l r
e
sear
ch
er
s
h
a
v
e
pu
t fo
rw
ard
a ser
i
es of
pr
in
ted
Y
a
g
i
-
U
d
a
an
ten
n
a
s,
whic
h can
be
easier to inte
grate for com
m
unication ci
rcui
t
s
. Thi
s
pa
per
pr
o
p
o
s
ed
a no
vel
K
o
c
h
fract
al
m
onopole Ya
gi-Uda a
n
tenna
and the m
o
nopoles'
ground
pl
ane acts a
s
the
ground
pl
ane
of the
ante
nna
,
whic
h
can
h
e
l
p
in
lower th
e
reson
a
n
t
freq
u
e
n
c
y
wh
ile th
e size in
th
e p
o
l
arizatio
n
d
i
rection stays th
e sa
me. Th
e
p
r
op
o
s
ed
an
tenn
a ach
i
ev
es t
h
e b
a
n
d
w
i
d
t
h
o
f
8
6
.2 MH
z, 119.3
M
H
z an
d 483
.9
MH
z at th
e r
e
so
n
a
n
t
fr
eq
uen
c
y
of
7.
8
1
G
H
z,
8.
54
G
H
z a
n
d 9
.
4
2
GHz
r
e
spect
i
v
el
y
.
Si
m
u
l
a
t
i
on o
f
a
n
t
e
n
n
a d
e
si
g
n
was car
ri
ed
out
by
C
o
m
put
er si
m
u
l
a
t
i
on t
e
c
h
ni
q
u
e
(C
ST)
M
W
st
udi
o s
o
ft
ware
[
7
]
.
2.
ANTE
N
N
A
S
T
RU
CTU
R
E
Th
e
d
e
si
g
n
of pr
opo
sed inno
v
a
tiv
e
K
o
ch
f
r
actal
Y
a
g
i
-Ud
a
an
tenn
a is show
n in f
i
gu
r
e
1. The
param
e
t
e
r use
d
f
o
r
desi
gni
n
g
t
h
e
pr
o
pos
ed
an
t
e
nna
i
s
defi
ne
d i
n
Ta
bl
e
1.
T
h
e FR
-4
l
o
s
s
y
resi
n
b
o
ar
d
wi
t
h
t
h
e
rel
a
t
i
v
e pe
rm
itt
i
v
i
t
y
4.4 i
s
u
s
ed wi
t
h
l
e
n
g
t
h
18
0 m
m
, wi
dt
h 7
0
m
m
and h
e
i
ght
o
f
2 m
m
. On
o
n
e si
de
o
f
resi
n
boa
r
d
t
h
e
ant
e
nna
i
s
pri
n
t
e
d
and
ot
her
si
de
i
s
gr
o
u
n
d
pl
an
e. I
n
t
h
e fi
gu
re
1,
t
h
e el
ect
ri
c
l
e
ngt
h
o
f
m
o
n
o
p
o
l
e
s'
refer to th
e leng
th
al
o
n
g
t
h
e +
y
di
rect
i
o
n a
n
d
t
h
e l
e
n
g
t
h
of
r
e
si
n
boa
rd
i
s
c
onsi
d
er
al
o
n
g
t
h
e +
x
di
rect
i
o
n
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE
Vo
l. 3
,
N
o
. 4
,
Aug
u
s
t 2
013
:
45
6
–
46
0
45
7
Fi
gu
re
1.
S
k
et
ch
of
K
o
c
h
f
r
act
al
y
a
gi
-u
da a
n
t
e
nna
. L=l
e
ngt
h
,
D=
wi
dt
h,
W=
t
h
i
c
kne
ss
B
y
di
vi
di
n
g
eq
ual
l
y
a li
ne segm
ent
i
n
t
o
t
h
ree part
s an
d re
pl
aci
ng t
h
e m
i
ddl
e pa
rt
wi
t
h
an i
s
oscel
es
triangle the
Koch fractal curve is obtai
ne
d [
8
]
.
I
n
t
h
i
s
pa
p
e
r a com
m
on case
is th
at th
e iso
s
celes triangle is an
eq
u
ilateral trian
g
l
e, wh
ich form
s th
e first-ord
e
r
Ko
ch
frac
t
al
, as sh
o
w
n
i
n
fi
g
u
r
e
1. B
y
di
vi
di
ng
t
h
e
t
h
ree
di
vi
de
d
pa
rt
s
as t
h
e
sam
e
st
eps a
b
o
v
e
,
hi
g
h
er
-o
r
d
er Koc
h
fractal curve
ca
n be
obtaine
d
. The
curve
th
eoretically c
a
n
ach
i
ev
e an
i
n
fi
n
ite len
g
t
h
wh
ile th
e
a
r
ea surrounded by the
curve
stays the sam
e
. The
r
efore
,
this practice ha
s rece
ntly been widely
a
ppl
i
e
d t
o
ac
hi
e
v
e an
t
e
nna m
i
ni
at
uri
zat
i
on [
9
-1
0]
.
The a
n
t
e
n
n
a c
o
nsi
s
t
s
of one
drive
n
ele
m
ent, one
reflector and t
h
ree
dir
ectors.
The a
n
tenna
is excited by
the SM
A c
o
nnector.
SMA c
o
nnect
ors
are
co
ax
ia
l
RF connectors
de
vel
o
ped i
n
t
h
e 19
6
0
s as
a
m
i
nim
a
l
connect
or
in
terface
fo
r
coaxial cable
with
a screw typ
e
coup
lin
g
m
echanism
.
The connector has a
50
Ω
i
m
peda
nce
.
It is place
d at the
one
en
d
o
f
t
h
e
dri
v
en
el
em
ent an
d ca
n
be see
n
i
n
re
d c
o
l
o
r i
n
t
h
e
fi
gu
re
1.
Tabl
e 1. Param
e
t
e
rs
f
o
r
t
h
e de
si
gn
o
f
pr
o
pos
ed
a
n
t
e
n
n
a.
Par
a
m
e
ter Dim
e
nsion
(m
m
)
Par
a
m
e
ter
Dim
e
nsion
(m
m
)
L
1
4.
5 L
14
17.
9
L
2
7.
7 L
15
16.
9
L
3
6.
7 W
1
2
L
4
7.
09
W
2
5.
1
L
5
9.
11
W
3
2
L
6
8.
7 D
1
105
L
7
24.
4
D
2
63
L
8
11.
7
D
3
.3
L
9
10.
7
D
4
1.
1
L
10
14.
7
D
5
15
L
11
14.
7
D
6
3
L
12
13.
7
D
7
26
L
13
17.
9
D
8
26
3.
SIMULATION RESULTS
The si
m
u
l
a
t
e
d resul
t
o
f
t
h
e
p
r
op
ose
d
a
n
t
e
n
n
a
i
s
sh
ow
n i
n
fi
gu
re
2, i
n
di
cat
i
ng t
h
e
gra
p
h
o
f
ret
u
r
n
l
o
ss
verse
f
r
eq
ue
nc
y
.
The
pr
o
p
o
s
e
d
a
n
t
e
n
n
a ha
s
ret
u
r
n
l
o
ss
of
-
1
9
.
5
dB
,
-
24
.
6
dB
an
d -
5
0.
8 dB
at
t
h
e re
s
ona
nt
Evaluation Warning : The document was created with Spire.PDF for Python.
I
J
ECE
I
S
SN
:
208
8-8
7
0
8
D
e
sign
an
d Ana
l
ysis o
f
Tripp
l
e Band
Ko
ch
Fra
c
ta
l
Yag
i
U
d
a
An
tenna
(Sa
t
ya
nd
ra
S
i
ngh
l
o
dh
i)
45
8
fre
que
nci
e
s
of
7.
8
1
G
H
z,
8
.
5
4
GHz
an
d
9.
45
G
H
z
res
p
ect
i
v
el
y
.
T
h
e
pr
o
p
o
s
ed
Ya
gi
-
U
da a
n
t
e
nn
a ha
s
achi
e
ve
d t
h
e
b
a
nd
wi
dt
h
of
8
6
.
2 M
H
z,
1
1
9
.
3
M
H
z an
d
4
8
3
.
9 M
H
z
at
res
p
ect
i
v
e res
ona
nt
fre
q
u
ency
as
s
h
o
w
n
i
n
fi
g
u
r
e
2.
Fi
gu
re
3 s
h
ows
t
h
e sm
i
t
h
chart
[1
1]
o
f
t
h
e
p
r
o
pos
ed
K
o
ch
f
r
act
al
Yagi
-
U
da
ant
e
n
n
a,
Im
pedance
match
i
n
g
is analyzed
b
y
inv
e
stig
atin
g
th
e Smith
ch
ar
t of
an
tenn
a
wh
ich sho
w
s th
at the im
pedance
of the
an
tenn
a is m
a
t
c
h
e
d with feed
i.e. 50
Ω
fo
r 9.4
2
GH
z.
Tabl
e
2. T
h
e
si
m
u
l
a
t
e
d res
u
l
t
s
o
f
pr
op
ose
d
K
o
ch
f
r
act
al
Ya
gi
-
U
da
ant
e
nna
.
Resonant fr
equenc
y
(GHz)
Retur
n
loss (
d
B)
Ba
ndwidth (MHz)
Gain (d
B) Directivit
y
(dBi)
7.
81
-
19.
5
86.
2
9.
67
10.
66
8.
54
-
24.
6
119.
3
10.
4
11.
03
9.
42
-
50.
8
483.
9
10.
6
11.
30
Fig
u
r
e
2
.
Retu
rn
loss
o
f
pr
oposed
K
o
ch fr
actal Y
a
g
i
-
U
d
a
anten
n
a
.
Fi
gu
re
3.
Sm
i
t
h C
h
art
of
p
r
o
p
o
se
d K
o
c
h
frac
t
al
Yagi
-
U
da a
n
t
e
n
n
a at
9.
4
2
GHz
.
The ra
di
at
i
on
pat
t
e
rn o
f
t
h
e pr
o
pose
d
ant
e
n
n
a i
s
sho
w
n i
n
fi
g
u
re 4
,
5 an
d
6. The ra
di
at
i
on
pat
t
e
rn o
f
fi
g
u
re
4
sh
o
w
s
t
h
e di
rect
i
v
i
t
y
of
1
0
.
6
6 dB
i
at
t
h
e res
ona
nt
fr
eque
ncy
7.
8
1
GHz
,
t
h
e
ra
di
a
t
i
on pat
t
e
rn
of
fi
g
u
re
5
sh
ows t
h
e d
i
rectiv
ity eq
u
a
l
to
11
.03
d
B
i at
th
e reson
a
nt
fr
eque
ncy
of
8.
5
4
G
H
z a
n
d t
h
e
radi
at
i
o
n
pat
t
e
rn
o
f
figu
re
6
sh
ows th
e d
i
rectiv
ity is 1
1
.30
d
B
i at th
e reson
a
nt
fr
eque
ncy
of 9.
4
2
G
H
z.
Tabl
e 2
i
s
i
n
di
cat
i
ng t
h
e
al
l
results o
b
taine
d
at diffe
re
nt
r
e
so
nant fre
q
u
e
n
cy
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
S
SN
:
2
088
-87
08
I
J
ECE
Vo
l. 3
,
N
o
. 4
,
Aug
u
s
t 2
013
:
45
6
–
46
0
45
9
Fi
gu
re
4.
R
a
di
at
i
on
pat
t
e
rn
o
f
p
r
o
p
o
sed
K
o
c
h
fract
al
Ya
gi
-
U
da
ant
e
nna
at
7.
8
1
GHz
.
Fi
gu
re
5.
R
a
di
at
i
on
pat
t
e
rn
o
f
p
r
o
p
o
sed
K
o
c
h
fract
al
Ya
gi
-
U
da
ant
e
nna
at
8.
5
4
G
H
z.
Fi
gu
re
6.
R
a
di
at
i
on
pat
t
e
rn
o
f
p
r
o
p
o
sed
K
o
c
h
fract
al
Ya
gi
-
U
da
ant
e
nna
at
9.
4
2
GHz
.
4.
CO
NCL
USI
O
N
A n
ovel
K
o
c
h
fract
al
Yagi
-U
da ant
e
n
n
a i
s
pr
o
pose
d
wi
t
h
hi
g
h
gai
n
, hi
g
h
di
rect
i
v
i
t
y
and
hi
g
h
b
a
n
d
wi
dt
h
.
T
h
e
fi
rs
t
-
or
de
r
Koc
h
f
r
act
al
m
onop
ol
es are
ap
pl
i
e
d
t
o
o
b
t
a
i
n
a m
o
re
uni
f
o
rm
cur
r
ent
di
st
ri
b
u
t
i
o
n
o
n
the dire
ctor, folde
d
active m
o
nopole
and
reflecto
r
, and
wh
ich
h
e
lp
s i
n
in
creasi
n
g th
e an
tenn
a's d
i
rectiv
ity.
The p
r
op
ose
d
ant
e
n
n
a ha
s si
gni
fi
cant
re
duc
t
i
on i
n
t
h
e
ret
u
rn l
o
ss an
d ac
hi
eves t
h
e gai
n
o
f
9
.
6
dB
,
1
0
.
4
dB
,
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I
J
ECE
I
S
SN
:
208
8-8
7
0
8
D
e
sign
an
d Ana
l
ysis o
f
Tripp
l
e Band
Ko
ch
Fra
c
ta
l
Yag
i
U
d
a
An
tenna
(Sa
t
ya
nd
ra
S
i
ngh
l
o
dh
i)
46
0
10
.6
dB
,
di
rec
t
i
v
i
t
y
10.6
6
d
B
i
,
11
.0
3
dB
i
,
11
.3
0
dB
i
an
d ba
n
d
wi
dt
h
o
f
8
6
.
2
M
H
z
,
1
1
9
.
3 M
H
z a
n
d
48
3
.
9
M
H
z. Fr
om
above
res
u
l
t
s
i
t
is obse
r
ved t
h
at
t
h
ere i
s
a si
gn
i
f
i
cant
im
pro
v
e
m
e
nt
i
n
Yagi
-
U
da a
n
t
e
n
n
a i
n
C
&
X ban
d
.
REFERE
NC
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