View
0
Download
0
Category
Preview:
Citation preview
Compact Omnidirectional 28 GHz 22 MIMO
Antenna Array for 5G Communications
Md Nazmul Hasan, and Munkyo Seo School of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
Email: nazmul@skku.edu, mkseo@skku.edu
Abstract - A compact 28 GHz planar monopole antenna is
presented. The proposed antenna consists of a triangular shape
radiator having exponentially tapered edges. The antenna exhibits a measured impedance bandwidth from 28.2 to 30.7 GHz. Measured radiation pattern confirms its omnidirectional
nature with linear polarization. Being compact, with an area of 1012 mm2, the proposed antenna can easily be integrated in handheld devices for 5G communications. Moreover, a 22
MIMO antenna array is presented, yielding a measured envelope correlation coefficient less than 0.001.
Index Terms — Millimeter-wave antenna, 28 GHz antenna,
monopole antenna, MIMO array, 5G antenna.
1. Introduction
With a hoard of new promising features, the realization of
fifth generation (5G) mobile communication is expected very
soon [1]. The 28 GHz band has the advantage of the least
path loss due to its relatively small atmospheric absorption,
compared to higher mm-wave 5G bands, such as 38 GHz, 60
GHz and 73 GHz [2]. Low profile, small antennas are the
best candidates for the integration in host devices. Besides,
in order to achieve higher data rate by virtue of spatial
multiplexing, the use of MIMO antenna array is fundamental.
A 28 GHz combined beam antenna having two main
radiators is reported in [3]. Another 28 GHz miniaturized
antenna (441.34 mm3) is reported in [4]. An inkjet-printed
antenna operating at 27.75 GHz is reported in [5].
This work presents a compact planar omnidirectional 5G
antenna operating over 28.2−30.7 GHz, with an area of
10×12 mm2. Moreover, a 2×2 MIMO antenna array has been
designed, fabricated and tested, yielding a measured
envelope correlation coefficient (ECC) less than 0.001 which
signifies very low mutual coupling between the two antenna
elements. The proposed antenna is small enough for
integration in hand-held devices and Internet of Things (IoT)
targeting 28 GHz 5G communications.
Detailed design of the proposed antenna is discussed in
section 2, followed by section 3 providing the results.
Section 4 elaborates MIMO antenna array design and
measurement results.
2. Antenna Design
The proposed antenna consists of a triangular shape
radiator with exponentially tapered edges as shown in Fig.
1(a). Partial ground plane, as shown in Fig. 1(b), is used to
achieve wide band impedance matching. Rogers RT/Duroid
5880 substrate having a thickness of 0.38 mm, relative
permittivity of 2.2, and loss tangent of 0.0009 is used to
fabricate the antenna. Fig. 1(c) illustrates the 3D model of
the proposed antenna with connector. The fabricated antenna
is shown in Fig. 1(d). Table I lists the dimensional
parameters of the antenna.
Fig. 1. (a) Top view, (b) bottom view, (c) 3D Model and (d)
photo of the proposed antenna.
TABLE I
Dimensional Parameters of the Proposed Antenna
Parameter Value
(mm)
Parameter Value
(mm)
Parameter Value
(mm)
W 12 i 0.5 j 0.25
L 10 n 3.88 v 0.86
m 1.52 Mw 0.66 G 6.66
3. Results
The proposed antenna was designed in HFSS, and
measurements were performed in anechoic chamber with
Agilent E8364B network analyzer. The measured impedance
bandwidth is from 28.2 to 30.7 GHz, as shown in Fig. 2. The
measured return loss has a slight shift, which is attributed to
fabrication tolerance and soldering. Fig. 3 shows the
radiation patterns in E-plane and H-plane at 28 GHz. Table II
compares the proposed antenna with other works. The
[WeD1-4] 2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
39
proposed antenna is more compact than [5], while offering
wider impedance bandwidth than [3] and [4].
Fig. 2. Reflection coefficient of the proposed antenna.
(a) (b)
Fig. 3. Radiation patterns (a) E-plane and (b) H-plane.
TABLE II
Comparison of the Proposed Antenna with Other Works
Reference Operating frequency (GHz) Size (mm3)
This work 28.2−30.70 10120.38
[3]a 27.47−28.45 441.34
[4]a 27.75 15.53.50.0685
[5]b 26.8−29 19.9300.79 a Simulation based work; b Waveguide size not included
4. 22 MIMO Antenna Array
Fig. 4. (a) Top view, (b) bottom view and (c) photo of the
proposed 2×2 MIMO antenna array.
Based on the proposed antenna, a 2×2 MIMO antenna
array has been designed, fabricated and tested. Fig. 4(a)
shows the top view, and Fig. 4(b) shows the bottom view of
the MIMO array, where Wx and Wy are 12 mm and 24 mm,
respectively. The fabricated MIMO array is shown in Fig.
4(c). The measured ECC is less than 0.001 as shown in Fig.
5, which indicates negligible mutual coupling between the
antennas. The calculation of ECC was performed using (1)
formulated by Blanch et al [6].
Fig. 5. Envelope correlation coefficient (ECC) plot.
|S*11S12+S*21S22|2
ECC = ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ (1)
(1−(|S11|2+|S21|2)) (1− (|S22|2+|S12|2))
5. Conclusion
A planar omnidirectional miniaturized antenna operating
from 28.2 to 30.7 GHz is proposed. Additionally, a 2×2
MIMO antenna array with a measured ECC less than 0.001
is presented. The proposed antenna is suitable for 28 GHz
5G hand-held devices.
Acknowledgment
This research was supported by Basic Science Research
Program through the National Research Foundation (NRF)
of South Korea funded by the Ministry of Education (NRF-
2016R1D1A1B03934114).
References
[1] W. Hong, K.H. Baek, and S. Ko, “Millimeter-Wave 5G Antennas for
Smartphones: Overview and Experimental Demonstration”, IEEE
Trans. Antennas Propag., vol. 65, no. 12, pp. 6250−6261, Dec. 2017.
[2] J. Lee et al., “Spectrum for 5G: Global Status, Challenges, and
Enabling Technologies”, IEEE Commun. Mag., vol. 56, no. 3, pp.
12−18, Mar. 2017.
[3] K.M. Morshed, K.P. Esselle, and M. Heimlich, “Dielectric Loaded
Planar Inverted-F Antenna for Millimeter Wave 5G Hand Held Devices”, in Proc. European Conference on Antennas and
Propagation (EuCAP)., Davos, Switzerland, 2016 [4] W. Ahmed, and D. Budimir, “Inkjet-Printed Antennas for 28 GHz 5G
Applications”, in Proc. Asia-Pacific Microwave Conference (APMC),
2016, New Delhi, India. [5] J.S. Park, J.B. Ko, H.K. Kwon, B.S. Kang, B. Park, and D. Kim, “A
Tilted Combined Beam Antenna for 5G Communications using a 28
GHz Band”, IEEE Antennas Wireless Propag. Lett., vol. 15, pp.
1685−1688, Jan. 2016.
[6] S. Blanch, J. Romeau, and L. Corbella, “Exact Representation of Antenna System Diversity Performance from Input Parameter
Description”, Electron. Lett., vol. 39, no. 9, pp. 705−707, May 2003.
2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
40
Recommended