Frequency GHz
2.30 2.35
2.40 2.45
2.50 2.55
2.60
M a
g n
it u
d e
d B
-0.6 -0.4
-0.2 0.0
10 20
30 40
50 60
Frequency GHz
2.0 2.2
2.4 2.6
2.8
R e
fl e
ct io
n P
h a
se d
e g
re e
-200 -100
100
10 20
30 40
50 60
a b
Frequency GHz
2.2 2.3
2.4 2.5
2.6 2.7
2.8
M a
g n
it u
d e
d B
-0.30 -0.25
-0.20 -0.15
-0.10 -0.05
0.00
10 20
30 40
50 60
Frequency GHz
2.0 2.2
2.4 2.6
2.8
R e
fl e
ct io
n P
h a
se d
e g
re e
-200 -100
100
10 20
30 40
50 60
c d
Frequency GHz
2.3 2.4
2.5 2.6
2.7
M a
g n
it u
d e
d B
-0.4 -0.3
-0.2 -0.1
0.0
0° 10°
20° 30°
40° 50°
60°
Frequency GHz
2.2 2.3
2.4 2.5
2.6 2.7
2.8
R e
fl e
c ti
o n
P h
a s
e d
e g
re e
-200 -100
100
0° 10°
20° 30°
40° 50°
60°
e f
Figure 8: Result of varying the incidence of angle to a and bSquare AMC c and d Rectangular AMC e and f Halfring AMC
IV. AMC
WITH
D
IPOLE
A
NTENNA
The purpose of designing an AMC is to increase the gain of antenna. However, the focus of designing AMC in this paper is to overcome the effect of metallic object on RFID tag. So, dipole antenna is designed at 2.45
GHz represented as the RFID tag that will be attached to the AMCs. In this part, each unit cell of AMCs is optimized into array arrangement. For Square AMC, two size of AMC with 2 x 2 and 4 x 1 arrangement is
presented. From the simulation graph in Figure 9a, the Square AMC with 2 x 2 arrangement give result return loss = -6.57 dB, gain = 5.94 dB and directivity = 7.82 dBi. For 4 x 1 square AMC arrangement, the value if gain
and directivity give not much different, but the return loss is increased in negative part to -8.48 dB. For rectangular AMC, the optimized AMC with 16 x 2 arrangement give much better result that the 8 x 1
arrangement with 68.42 of increment for return loss. The Halfring AMC also shows that the optimized AMC with bigger size 19 x 4 arrangements give better result that the 9 x 2 arrangement in term of return loss value
while the gain and directivity were increased too but just in small range. Maisarah Abu et al. International Journal of Engineering and Technology IJET
ISSN : 0975-4024 Vol 6 No 1 Feb-Mar 2014
432
Frequency GHz
1.8 2.0
2.2 2.4
2.6 2.8
3.0
R e
tu rn
L o
ss d
B
-12 -10
-8 -6
-4 -2
2
with Square AMC ground plane of 64 mm x 64 mm with Square AMC ground plane of 128 mm x 32 mm
with PEC ground plane
30 60
90 120
150 180
210 240
270 300
330
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
with Square AMC ground plane of 64 mm x 64 mm with Square AMC ground plane of 128 mm x 32 mm
with PEC ground plane
a b
Frequency GHz
2.0 2.2
2.4 2.6
2.8
R e
tu rn
L o
ss d
B
-25 -20
-15 -10
-5 5
with Rectangular AMC ground plane of 62 mm x 62 mm with Rectangular AMC ground plane of 32 mm x 32 mm
with PEC ground plane
30 60
90 120
150 180
210 240
270 300
330
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
with PEC ground plane with Rectangular AMC ground plane of 64 mm x 64 mm
with Rectangular AMC ground plane of 32 mm x 32 mm
c d
Frequency GHz
2.40 2.42
2.44 2.46
2.48 2.50
R e
tu rn
L o
ss d
B
-20 -15
-10 -5
with halfring AMC ground plane of 62.9 mm x 62.9 mm with halfring AMC ground plane of 130 mm X 130 mm
with PEC ground plane
30 60
90
120 150
180 210
240 270
300 330
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
-25 -20
-15 -10
-5 -25
-20 -15
-10 -5
with halfring AMC ground plane of 62.9 mm x 62.9 mm with halfring AMC ground plane of 130 mm X 130 mm
with PEC ground plane
e f
Figure 9: Return loss and radiation pattern for optimized AMCs
ISSN : 0975-4024 Vol 6 No 1 Feb-Mar 2014
433
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