[FrP-02]

2018 International Symposium on Antennas and Propagation (ISAP 2018)
October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

MACKEY type T Covering WiFi 2 GHz / 5 GHz
Bands*Ken Hirano, *Shigeru Makino, *Keisuke Noguchi, *Tetsuo Hirota, *Kenji Itoh
*Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa, JapanIntroduction

An antenna model MACKEY (meta-surface inspired
antenna chip developed by KIT EOE laboratory), integratinga dipole antenna and an artificial magnetic conductor (AMC),
was developed [1]. It was shown that the MACKEY can matchthe impedance even when installed in free space or on a metalplate.
The proposed MACKEY satisfies each of WiFi 2 GHz andWiFi 5 GHz bands. However, one antenna cannot cover thesebands as the bandwidth of WiFi 5 GHz is too wide. In orderto obtain dual-band characteristics, a MACKEY parallel
arrangement model was proposed in which an original
MACKEY (WiFi 2 GHz band) and a MACKEY wide-band
type (WiFi 5 GHz band) are arranged in parallel [2]. In thispaper, a MACKEY type T model is proposed, where one ofthe two grids of an original Mackey and that of a wide-band
type are shared.

Analyzed Result of a Parallel Arrangement Model

The design parameters of the parallel arrangement model
are g = 26.8 mm, gg = 10 mm, ℓ = 27.9 mm, ℓℓ = 14.3 mm,
sp = 4 mm, and ww = 1.0 mm. Therefore, the size is 30 mm
× 79.5 mm × 4.0 mm. Fig. 2 shows the VSWR characteristicof the parallel arrangement model in free space and illustrates
that the parallel arrangement model covers the WiFi 2 GHz / 5GHz bands. Fig. 3 shows the radiation patterns of the parallel
arrangement model in free space at 2.45 GHz, 5.25 GHz and5.60 GHz, respectively. From Fig. 3, the analyzed gains are
6.1 dBi, 5.8 dBi, and 7.6 dBi, respectively. Therefore, theparallel arrangement model works for WiFi 2 GHz / 5 GHz
bands and the minimum sp is 4 mm to reduce the influence ofmutual coupling.

10987
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3
2
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10
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4
3
2
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VSWR

1.

3.

VSWR

Abstract — A meta-surface inspired antenna (MACKEY)
was proposed, which works not only in free space but also on ametal plate. A MACKEY parallel arrangement model wasproposed in which an original MACKEY (WiFi 2 GHz band) anda MACKEY wide-band type (WiFi 5 GHz band) are arranged inparallel. In this paper, a MACKEY type T is proposed, where
one of the two grids of an original Mackey and that of a wideband type are shared.
Index Terms — WiFi 2 GHz band, WiFi 5 GHz band

22.1

2.2

2.3

2.4

2.5

2.6

Frequency[GHz]

2.7

2.8

2.9

Theta(Analysis)Fig. 1 shows the structure of the parallel arrangement model.
It is composed of two dipole antenna, four grids and two metal
plates in order from the top, and dielectric substrate among
them. In WiFi 2 GHz band, impedance matching is possible bydetermining the optimum combination of ℓ and g. In WiFi 5
GHz band, impedance matching is possible by determining theoptimum combination of ℓℓ and gg. The slit width (sp) is adistinctive parameter for the parallel arrangement model, andis provided to reduce the influence of mutual coupling.
ℓW=30①

h=0.74②t=3.12③

Original MACKEY

Wide-band
typeSide viewMetal plate

Dielectricℓℓ

wws=0.5s=0.5①Antenna plateg s=0.5gsp gg s=0.5gg② Grid plate

L=2(g+gg+s)+sp③ Metal plate

Fig. 1. Structure of a parallel arrangement model.

5.1

5.2

5.3

5.4

5.5

5.6

Frequency[GHz]

5.7

5.8

5.9

6Fig. 2. VSWR characteristics of a parallel arrangement
model.

Structure of a Parallel Arrangement Model

Feedingpoint

5in free spce(5GHz～6GHz)

XY面

2.

3

in free spce(2GHz～3GHz)

20 X
100-10-20-30

XZ面

Y20 Z
100-10-20-30

X

in free space (2.45GHz)

XY面
20 X
100-10-20-30

XZ面
20 ZY

100-10-20-30

in free space (5.25GHz)

XY面

X2010 X
0-10-20-30

XZ面

Y2010 Z
0-10-20-30

X

in free space (5.60GHz)

Fig. 3. Radiation patterns of a parallel arrangement model.
4.

Idea to Minimize a Parallel Arrangement Model

A method for sharing the grids of the original MACKEY andthe wide-band type was proposed to reduce L of the parallel
arrangement model [2]. Fig. 4 shows the sharing model of thegrids. The green dotted line works in the WiFi 2 GHz band,and the blue dotted line works in the WiFi 5 GHz band.
Compared with the parallel arrangement model, theoverlapping part of the green and blue dotted lines works as a823

2018 International Symposium on Antennas and Propagation (ISAP 2018)
October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea

grid of different frequency bands. Therefore, the number ofgrids becomes triple, and L is small. A MACKEY type T (triplegrids type: type T) is proposed, where the number of grids istriple. The grid widths corresponding to one frequency areasymmetric on the left and right. A MACKEY type A(Asymmetry type: type A) was proposed as a model in which
the left and right grids are asymmetric [2]. In the figure, the slitof WiFi 2 GHz band acts as sp to reduce the influence ofmutual coupling. Therefore, the sp of the grid in WiFi 2 GHzband is set to 4 mm where the influence of mutual coupling issmall. Also, the slit of WiFi 5 GHz band is set to 0.5 mm.

10987654321MACKEY parallel arrangement typeAnalysisMeasure
2③

2.1

2.4

2.5

2.6

Frequency[GHz]

2.7

2.8

sp
MACKEY type T (Triple grids type)Fig. 4. Idea to reduce length of a parallel arrangement model.

55.1

5.2

5.3

5.4

5.5

5.6

Frequency[GHz]

5.7

5.8

sp=4

4
Side view

2.4

2.5

2.6

Frequency[GHz]

2.7

2.8

2.9

3

5.8

5.9

6

Analysis
Measure

65

5.1

5.2

5GHz～6GHz

5.3

5.4

5.5

5.6

Frequency[GHz]5.7

on metal (5GHz～6GHz)Y

g1=36.8

20
10 Z
0-10-20-30

X

Analysis
Measureww2=1
g2=12XZ面

Y2010 Z0-10-20-30

X

Fig. 5. Structure of a MACKEY type T.
Measured Result

XZ面

Y20Z
100-10-20-30

Xon metal (2.45GHz)
XZ面
XY面

XY面

20X
100-10-20-30

Y2010 Z
0-10-20-30

on metal (5.25GHz)

Fig. 6 shows the VSWR characteristics of type T in freespace and on a metal plate. The solid black and red lines
indicate the VSWR characteristics obtained from the analyzed
results and the measured results, respectively. From Fig. 6, theanalyzed results and the measured results coincide very well.
The measured bandwidth in free space is more than 6.5 % (2- 3 GHz) and 13.6 % (5 - 6 GHz) and covers the WiFi 2 GHz/ 5 GHz bands. The measured bandwidth on a metal plate ismore than 4.2 % (2 - 3 GHz) and 16.0 % (5 - 6 GHz) andcovers the WiFi 2 GHz / 5 GHz bands.
Fig. 7 shows the radiation patterns of type T model in freespace at 2.45 GHz, 5.25 GHz and 5.60 GHz, respectively. The
black and red lines indicate the radiation patterns obtained20X100-10-20-30in free space (5.60GHz)

XY面

20X
100-10-20-30

s=0.5

s=0.5
gg=8X

Fig. 7. Radiation patterns in free space.

ℓℓ2=12.7

ww1=8.3

XZ面

20Z
100-10-20-30

in free space (5.25GHz)

Top view

6.

2.3

in free space (2.45GHz)
XZ面
XY面

XY面

2010 X
0-10-20-30ℓℓ1=36.8

W

s=0.5

5.9Analysis
MeasureL=g+g1+g2+sp+s=56.8

s=0.5

2.2

on metal (2GHz～3GHz)

10987654321

XY面

Fig. 5 shows the design parameters of type T. As a result ofdesigning type A that covers the WiFi 2 GHz / 5 GHz bands,
the shared grid width (gg) is set to 8 mm. For type T in theWiFi 2 GHz band, impedance matching is possible bydetermining the optimum combination of ℓℓ1 and g1. For type
T in the WiFi 5 GHz band, impedance matching is possible bydetermining the optimum combination of ℓℓ2 and g2. The sizeof the designed type T is 30 mm × 56.8 mm × 4.0 mm, which
is downsized by about 30% compared with the parallel
arrangement model.

sp=42.1Fig. 6. Comparison of VSWR characteristics.

Structure of a MACKEY type T

s=0.5Analysis
Measure23Analysis
Measurein free space (5GHz～6GHz)

5.

2.9VSWR②③ Antenna for WiFi 5 GHz

2.3

in free space (2GHz～3GHz)

1098
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654
32
1①② Antenna for WiFi 2 GHz

2.2VSWR②VSWR

Antenna for WiFi 2 GHz
Antenna for WiFi 5 GHz

①1098
7
6
543
2
1VSWR

spfrom the analyzed results and measured results, respectively.
In the figure, the solid lines indicate the Eθ component. FromFig. 6, the measured gains are 5.5 dBi, 4.5 dBi, and 3.6 dBi,respectively. Fig. 8 shows the radiation patterns of type Tmodel on a metal plate at 2.45 GHz, 5.25 GHz, and 5.6 GHz,respectively. From Fig. 8, the measured gains are 8.5 dBi, 6.0dBi, and 6.3 dBi, respectively.
Therefore, type T model is shown to not only work in freespace but also on a metal plate over the WiFi 2 GHz / 5 GHz
bands.

X

2010 X
0-10-20-30

XZ面Y20Z
100-10-20-30

X

on metal (5.60GHz)

Fig. 8. Radiation patterns on a metal plate.
7.

Conclusion

The MACKEY type T was proposed, which works in theWiFi 2 GHz / 5 GHz bands; it works in free space as well as
on a metal plate. Also, type T was downsized by about 30%
compared with the parallel arrangement model.
References
[1]
[2]

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T. MOROYA et al, “AMC Inspired Small Antenna MACKEY,” IEICE.
Trans. Commun, vol. J99-B, no. 9, pp. 786–794, Sep. 2016.
K. HIRANO et al, “Feasibility Study of MACKEY type A,” IEICE. Tech.
Rep, AP2017-110, pp. 15-20, 2017.