ANTENNA DESIGN
The configuration of the proposed
antenna is shown in Figure 1, with
dimensions of Wsub = 7 mm, Lsub =
0
S1=6mm S1=4mm S1=2mm
43. 96 mm and H = 0.8 mm. The proposed dual-band dipole antenna is
printed on an FR4 substrate with a
relative dielectric constant εr = 4. 4
and a thickness H = 0.8 mm. The proposed antenna is fed in the middle of
the structure and connected to a 50
V mini coaxial line. The basis of the
antenna structure is two rectangular
arms with dimensions of W1 = 5 mm
and L1 = 16. 53 mm. The horizontal
design, a T-shape slit, is embedded
in each arm of the rectangular dipole
antenna to generate a new resonant
mode at 5.2 GHz. Combining the 2.4
GHz band of the rectangular dipole
antenna and the 5.2 GHz band newly
generated meets the requirements of
WLAN systems.
RETURN LOSS (dB)
10
20
30
40
1
EXPERIMENTAL RESULTS AND
DISCUSSION
CO-POL CROSS-POL
54
FREQUENCY (GHz)
32
6
120
120
s Fig. 2 Measured return loss for different
S1.
150
180
180
90
0
30
60
– 10
– 20
– 30
– 40 – 10 – 20 – 30
150
0
S2=1mm S2=3mm S2=5mm
210
210 330
RETURN LOSS (dB)
10
20
30
40
21
240
300
240
Y-Z PLANE
270
X-Z PLANE
270
2.4 GHz
120
76
54
FREQUENCY (GHz)
3
150
s Fig. 3 Measured return loss for different
S2.
180
150
180
90
0
30
60
– 10
– 20
– 30
– 40 – 10 – 20 – 30
120
210
330
210
0
L3 = 7. 53 mm L3 = 5. 53 mm L3 = 3. 53 mm
240
300
240
RETURN LOSS (dB)
10
20
30
40
1
Y-Z PLANE
270
X-Z PLANE
270
5.2 GHz
In this section,
dipole antennas
with various parameters (S1, S2 and L3)
were constructed
and studied to demonstrate the performances of the proposed design. The
simulated results are
obtained with Ansoft High Frequency
Simulation Software
(HFSS). Figure 2
shows the measured
return losses of different slit lengths S1
with other dimensions: G = 0.9 mm,
L1 = 16. 53 mm,
L2 = 5 mm, L3 = 5
mm, L4 = 6 mm,
W1 = 5.mm, W2 =
2 mm, W3 = 2.mm
and S2 = 1 mm. The
resonance characteristics of these
antennas are listed
in Table 1. When
S1 decreases, the
300
330
300
330
90
0
30
60
– 10
– 20
– 30
– 40 – 10 – 20 – 30
90
0
30
60 – 10
– 20
– 30
– 40 – 10 – 20 – 30
s Fig. 6 Measured radiation patterns in the y-z and x-z planes for
the proposed antenna.
TABLE I
56
4
FREQUENCY (GHz)
32
7
s Fig. 4 Measured return loss for different L3.
MEASURED SIMULATED (HFSS)
0
RETURN LOSS (dB)
10
20
30
40
1
RESONANCE CHARACTERISTICS FOR DIFFERENT S1 LENGTHS
S1 (mm) 1st Resonant
Frequency (GHz)
1st Bandwidth
(%)
2nd Resonant
Frequency
(GHz)
2nd Bandwidth
(%)
6
5.05
4
5. 44
2 5. 41
2.41
2.49
2.55
16. 6
17. 27
16.08
11. 49
12. 5
5. 55
543
FREQUENCY (GHz)
2
6
s Fig. 5 Measured and simulated return
loss of the proposed antenna.
patch is combined with a triangular
patch and a rectangular patch (W2 =
2 mm, L2 = 5 mm), forming a rectangular dipole plate. The left and
right plates are symmetrically placed
on both sides of the feed point, with
a feed gap G fixed at 0.9 mm. The
dipole antenna1 can generate a frequency resonance at 2.4 GHz. In this
TABLE II
RESONANCE CHARACTERISTICS FOR DIFFERENT S2 LENGTHS
S2 (mm) 1st Resonant
Frequency (GHz)
1st Bandwidth
(%)
2nd Resonant
Frequency
(GHz)
2nd Bandwidth
(%)
1 2.41 16. 6 5.05
3 2.44 14. 75 5. 89
5 2.5 17. 6 6. 77
11. 49
9. 51
