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1Date of publication xxxx 00, 0000, date of current version xxxx 00, 0000.
Digital Object Identifier 10.1109/ACCESS.2017.Doi Number
Wideband Monopole Eight-Element MIMO
Antenna for 5G Mobile Terminal
Anju Kumari Rai1, Member, IEEE, Rahul Kumar Jaiswal1, Member, IEEE, Kahani Kumari1,
Member, IEEE, Kumar Vaibhav Srivastava1, Senior Member, IEEE, Chow-Yen-Desmond
Sim2, Senior Member, IEEE
1
Electrical Engineering Department, Indian Institute of Technology, Kanpur, 208016, India
Electrical Engineering Department, Feng Chia University, Taichung, 407, Taiwan
2
Corresponding author: Anju Kumari Rai (e-mail: anjukumarirai@gmail.com), Chow-Yen-Desmond Sim (e-mail: cysim@fcu.edu.tw).
This work was supported in part by the Ministry of Science and Technology (MOST), Taiwan, under project no. MOST 111-2221-E-035-022. It
was also partly supported by Science and Engineering Research Board, India, under project no. CRG/2021/000376.
ABSTRACT An eight-element wideband multiple-input multiple-output (MIMO) antenna for the fifthgeneration (5G) mobile terminal is proposed. The antenna elements are placed along both long side edges of
the mobile terminal with a profile of 6 mm. The proposed monopole-inspired antenna element shows a good
impedance match, isolation, and diversity parameter across a very wide bandwidth of 78 % (3.2-7.3 GHz),
and it can cover the 5G NR n77/n78/n79/n96, LTE 46, and WLAN 5 GHz bands. The result shows that the
MIMO antenna can offer inter-element isolation better than 12 dB, envelope correlation coefficient (ECC)
below 0.069, and a peak channel capacity of 42.7 bps/Hz across the desired 5G bands. The specific absorption
rate (SAR) analysis of the proposed MIMO antenna with a human head has exhibited SAR levels (0.41 W/Kg
and 0.33 W/Kg at two resonating frequencies 3.9 GHz and 5.8 GHz, respectively) much lower than the
Federal Communications Commission (FCC) permissible limit (1.6 W/Kg over 1 gram tissue).
INDEX TERMS 5G mobile , MIMO antenna, specific absorption rate (SAR), sub-6 GHz, wideband.
I. INTRODUCTION
In the course of development in wireless cellular
technology, fifth-generation (5G) communication systems
are adopted to provide low latency and high data rate
experience for network users [1]. Antennas are an essential
component of wireless technology. Their application in 5G
communication is highly dynamic depending upon different
specific requirements such as broad bandwidth [2-3],
polarization agility, reconfigurability [4], etc., along with
common basic parameters. To satisfy the large throughput
requirement for a 5G mobile terminal, a multiple antennaelement based MIMO antenna array is employed in the
mobile terminal, which leads to the three main aspects of the
5G mobile terminal MIMO antenna, namely, antenna
placement, bandwidth, and compatibility for users. In the
existing literature [5]-[7], the earlier generation antennas are
generally placed at the two extremes (top and bottom section)
of the mobile terminal. To further integrate the 5G antenna
array into the mobile terminal, the prospective 5G array is
generally collocated along the longer edges of the
smartphone frame to be compatible with pre-existing
antennas [8]-[20].
As the 5G spectrum has stretched from its initial New
Radio (NR) bands n77/n78/n79 (3.3-5.0 GHz) to the wireless
local-area network (WLAN) 5GHz (5.15-5.825 GHz) bands
[21], it is noteworthy that the NR-unlicensed (NR-U) bands
of up to sub-7 GHz, known as n96 (5.925-7.125 GHz) have
also been introduced recently [22]. Therefore, it is vital to
satisfy the global 5G NR spectrums requirement by
designing a wideband antenna array. In [8]-[13], MIMO
antennas (with four- or eight-elements) have been
investigated to support a fraction of sub-6 5G NR bands. To
further cover the entire 5G sub-6 GHz, dual-band operating
eight-element MIMO antenna arrays have also been studied
[14]-[18]. Maintaining good isolation is an implicit term in
MIMO antenna system. To achieve desirable isolation
between the adjacent array elements of the MIMO antenna,
connecting lines or slot etching techniques have been
introduced [11]-[15]. However, the works above have
VOLUME XX, 2017
1
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indicated that it is difficult to realize a good isolation level
without using any extra decoupling structure.
To cover the entire 5G NR band n77/n78/n79, LTE band
46, WLAN 5G band, and 5G NR-U band n96, now referred
to as the bands of interest (3.3-7.125 GHz), [19] has
introduced an open slot-loaded metal rim 8-antenna MIMO
array that can cover the bands of interest with isolation >11
dB. Subsequently, a 4-antenna MIMO array comprised of 2
PIFA pairs has also been developed with a wide bandwidth
of 78% (3.3-7.5 GHz), but it has an isolation of >10 dB [20].
Notably, the profile of antenna configuration for mobile
terminal discussed in [8]-[10], [16], [17], [18] is in order of
7 mm or more. As the average thickness of a flagship
smartphone is about 0.35 inches (8.93 mm), its designated
array antennas should have a profile (antenna height) of no
more than 6 mm. To achieve such a profile, [12]-[15] have
applied the technique of using either surface mount devices
(SMDs) or defected ground structure method, but at the cost
of design complexity. Nevertheless, achieving wide
bandwidth, good isolation, and diversity performance
parameters with low-profile characteristics for a large
MIMO array is challenging. Therefore, the design of the
proposed MIMO antenna array that is simple in structure and
presents no fabrication complexity for the upcoming 5G
environments without compromising the antenna array
performances is imperative to the antenna industry.
This paper proposes an eight-element MIMO antenna
array with wide 6-dB impedance bandwidth of 78% (3.2-7.3
GHz) across the bands of interest, and it has exhibited good
isolation of >12 dB without introducing the extra decoupling
structure. Besides showing a low profile of only 6 mm, the
proposed antenna array has also demonstrated good MIMO
performance with desirable radiation patterns. Finally, the
SAR analysis considering a mobile terminal with a human
head to guarantee the user compatibility of the proposed
antenna array is conducted.
This manuscript is organized as follows. Firstly, the
geometrical configuration of the proposed wideband eightelement MIMO antenna, along with its design evolution
steps and working principle of operation, are discussed in
section II, followed by simulated and experimental results in
section III. Finally, section IV concludes the paper.
II. ANTENNA DESIGN AND WORKING PRINCIPLE
A. ANTENNA GEOMETRY
Figures 1(a) and 1(b) depict the detailed geometry of the
single antenna element and the layout of the proposed MIMO
antenna, respectively. The proposed MIMO antenna is
designed on FR4 substrates having a thickness of 0.8 mm,
dielectric constant of 4.4, and loss tangent of 0.02. The antenna
element is a rectangular monopole-inspired antenna; its
feeding structure is a microstrip line of width 2.2 mm fed with
an SMA connector. The overall dimension of each antenna
element is 21.5 mm × 5.2 mm. The system ground plane has a
FIGURE 1. (a) Detailed geometry of single antenna element with the design
parameters (unit: mm): l1 = 21.5, l2 = 9.5, l3 = 0.9, w1 = 5.2, w2 = 4, w3 = 1 (b)
layout of the proposed eight-element MIMO antenna.
dimension of 150 mm × 72.6 mm printed on an FR4 substrate
(150 mm × 75 mm). The clearance between the outer edges of
the ground plane and substrate is 1.2 mm on each side. The
two-reserved regions (#A and #B) of dimensions 15 mm × 75
mm are for the placement of main and diversity antennas
(3G/4G/WLAN/WiFi etc.). The proposed antenna elements
are printed on the inner surface of two standing FR4 substrates
(150 mm × 5.2 mm) along the longer side edges of the ground,
which can be considered as the smartphone frame. Therefore,
the proposed MIMO antenna is compatible with a 6 mm sleek
mobile terminal. Here, the proposed eight-element MIMO
antenna is subdivided into two 1 × 4 arrays (ANT 1-ANT 4
and ANT 5-ANT 8), which are symmetric along the center of
the system ground. The gap between ANT 1 and ANT 2 is d1
= 11.2 mm, and the gap between ANT 2 and ANT 3 is d2 =
11.6 mm.
B. DESIGN EVOLUTION OF PROPOSED ANTENNA
ELEMENT AND ITS WORKING PRINCIPLE
The proposed MIMO antenna design is inspired by a
rectangular monopole antenna to achieve wide impedance
bandwidth. The impedance bandwidth can be significantly
increased by reducing the width of the square monopole
antenna [23]. The design evolution phases of the single
element (ANT) and their reflection coefficients are shown in
Fig. 2. Section 1 is a conventional rectangular monopole
antenna of a length slightly greater than a quarter-guided
wavelength corresponding to its resonance frequency (5.8
GHz). To excite a lower resonance frequency of the 5G NR
bands, a rectangular monopole antenna with an L-shaped
open slot is designed at 3.9 GHz resonance, which is now
denoted as Section 2. Here, one can see that Section 1 is
designed to cover NR n79/n96, LTE 46, and WLAN 5 GHz
2
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bands, while Section 2 covers NR band n78. Therefore, to
achieve a very wide bandwidth of 78% (3.2-7.3 GHz), it is
realized that these two Sections (1 and 2) designed at two
different resonance frequencies can be merged, which is
denoted as the proposed Ant element. Notably, the
impedance bandwidth at the lower band is further improved
by optimizing the feedline length. Finally, the proposed ANT
element can cover the entire 5G NR n77/n78/n79/n96, LTE
46, and WLAN 5 GHz bands.
FIGURE 4. Transmission coefficients of (a) configuration A. (b) configuration A’
FIGURE 2. Design evolutionary phases of single element with design
parameters (unit: mm): l1 = 21.5, l2 = 9.5, l3 = 0.9, l4 = 14.5, l5 = 11.1, w1 = 5.2,
w2 = 4 and their reflection coefficient.
To validate the performances of the proposed MIMO
antenna, the current distribution across the ANT 1 element at
two resonance frequencies, namely, f1 (3.9 GHz) and f2 (5.8
GHz), are depicted in Figs. 3(a) and 3(b), respectively. As
depicted in Fig. 3(a), it can be inferred that Section 2, along
with a portion of Section 1, is responsible for exciting the first
resonance at 3.9 GHz. Similarly, from Fig. 3(b), the
rectangular monopole portion of Section 1 is responsible for
the excitation of the 5.8 GHz resonance.
III. RESULT AND DISCUSSION
A prototype of the proposed MIMO antenna was
fabricated, and it is shown in Fig. 4. Measured results validate
the simulated results. The S-parameter is measured using the
N5222A PNA network analyzer (Agilent Technologies), and
the far-field parameters are measured in a standard anechoic
chamber.
FIGURE 3. Current distributions along ANT 1 (a) 3.9 GHz (b) 5.8 GHz.
The orientation of elements and spatial diversity technique are
simultaneously used to maintain isolation among antenna
elements. The antenna element is a combination of two
sections resonating at different frequencies; thus, adjacent
antenna elements (except ANT 2 - ANT 3 and ANT 6 - ANT
7 pairs to maintain symmetry) are placed in back-to-face
orientation to suppress the coupling. The two possible
configurations and their simulated transmission coefficients
response are shown in Fig. 4. It is observed that configuration
A exhibits better isolation level with respect to configuration
A’. Thus, the antenna elements are placed in accordance with
configuration A.
FIGURE 5. The fabricated prototype (a) top view (b) bottom view (c) side view.
3
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A. MATCHING AND ISOLATION
FIGURE 6. Reflection coefficients of ANT 1-4 (a) simulated (b) measured.
To verify that the proposed smartphone antenna has good
MIMO performances, the diversity parameter (ECC) of ANT
1-4 is calculated from the far field three-dimensional (3-D) Efield patterns, considering the uniform multipath environment
of balanced polarization. Fig. 7(a) shows the calculated ECC
values across the desired bands of interest, which are well
below 0.069. This result satisfies the acceptable ECC
threshold (< 0.3) for the MIMO antenna [24]. The channel
capacity of the eight-element MIMO antenna is also calculated
and plotted in Fig. 7(a). It is obtained from the simulated
results by averaging 1,00,000 independent identically
distributed (IID) Rayleigh fading channel realization with a
20dB signal-to-noise ratio (SNR) [25]. Here, a channel
capacity of > 39.5 bps/Hz (with a peak value of 42.72 bps/Hz)
is observed, and it is comparable to the channel capacity of an
ideal 8 × 8 MIMO antenna (46 bps/Hz).
FIGURE 7. Transmission coefficients of ANT 1-4 (a) simulated (b) measured.
The simulated and measured reflection coefficients of
ANT 1-4 are plotted in Figs. 5(a) and 5(b), respectively. The
results for ANT 5-8 are not shown for brevity. Here, the
simulated 6-dB stacked impedance bandwidth was 77% (3.2 7.2 GHz), and the measured one was 78% (3.2-7.3 GHz), and
they can well cover the 5G NR n77/n78/n79/n96, LTE 46, and
WLAN 5G bands. The simulated and measured isolation
levels between antenna elements (ANT 1-4) printed on the
same side edge are shown in Figs. 6(a) and (b), respectively.
Here, a desirable isolation level of better than 12 dB is
achieved. The worst isolation is among ANT 2 and ANT 3 at
the lower desired frequency range due to the Face-to-Face
configuration to maintain structural symmetry as per practical
requirements. In contrast, isolation of better than 12 dB is
achieved.
FIGURE 9. Simulated and measured radiation patterns of ANT 1 at 3.9 GHz and
B. MIMO PERFORMANCE, EFFICIENCY AND
RADIATION PATTERNS
FIGURE 8. (a) Calculated ECC and channel capacity (b) simulated and measured
total efficiency.
5.8 GHz across the xz and yz planes.
Fig. 7(b) shows the simulated and measured total
efficiency by exciting only antenna element ANT 1 (while the
others were terminated to 50Ω loads) of the proposed MIMO
antenna. Across the bands of interest, the simulated
efficiencies ranged from 61% to 77%, whereas the measured
ones were slightly lower, between 51% and 70%. The
differences between the two results could be due to slight
fabrication errors and tolerances
Figs. 8 and 9 depict the simulated and measured radiation
patterns of ANT 1 and ANT 2, respectively, at both resonance
frequencies (3.9 GHz and 5.8 GHz), while all the other
antenna elements are terminated to 50Ω loads. By observing
these two figures, one can see that majority of Eθ radiation is
4
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inclined towards the negative x direction. Thus, the direction
of the main beam radiation of ANT elements is pointing away
from the system, allowing good MIMO performance.
FIGURE 12. (a) Reflection Coefficient and (b) Transmission Coefficient in
single hand operation.
FIGURE 10. Simulated and measured radiation patterns of ANT 2 at 3.9 GHz and
FIGURE 13. (a) Reflection Coefficient and (b) Transmission Coefficient in two
5.8 GHz across the xz and yz planes.
hand operation.
C. USER’S HAND EFFECT AND SAR ANALYSIS
In this case, the commercial software HFSS (high frequency
structure simulator) are used to analyse the proposed antenna
system with inclusion of human hand phantom in two different
hand held situations, namely, single hand operation (SHO,
data mode) and two hand operation (THO, read mode), as
depicted in Figs. 11(a) and (b), respectively. The simulated Sparameters in single hand operation (SHO, data mode) and
two hand operation (THO, read mode) are depicted in Fig. 12
and Fig. 13, respectively. Transmission coefficients of S21S81 (port 1 with other ports) and S23 are evaluated because of
symmetry.
FIGURE 11. Simulated model of proposed antenna with a user’s hand in (a)
single hand operation and (b) two hand operation.
FIGURE 14. Simulated total efficiency of antenna system in single hand and
two hand operations.
In SHO and THO condition, the impedance matching of
ANT 6 and (ANTs 5 and 8), respectively, are highly affected,
in spite that each antenna elements are able to cover the
desired 5G bands with isolation level greater than 11 dB and
10 dB in the SHO and THO, respectively.
The simulated total efficiency of the antenna system in both
hand held situations are shown in Fig. 14. The total efficiency
under SHO and THO are greater than 58% and 32%,
respectively, whereas the simulated total efficiency of
proposed antenna system is greater than 61%. This is because
the hand tissues can absorb electromagnetic radiation energy,
causing the deterioration of antenna efficiencies. However, the
5
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simulated total efficiencies are still higher than 20%, which
are acceptable for 5G smartphone MIMO system with the
hand presence.
Along with the effects of user’s hand on antenna
performance, the biological implication on the users are also
indispensable. The specific absorption rate (SAR) can be
related to the electric field at a point in the human body, as
denoted in (1) [26],
2
SAR = σ E field ρ
(1)
where σ is the conductivity of the tissue (S/m), ρ is the density
of the tissue (kg/m3), and Efield is the root mean square value of
the electric field strength in tissue (V/m).
To validate the deplorability of the proposed MIMO
antenna in a 5G user terminal (smartphone), the SAR
analysis of the MIMO antenna while held against the ear is
investigated. The main reason for such evaluation is that the
human ear/brain could be affected (by high radiation) when
the mobile terminal is in a talk position. Here, the MIMO
antenna array is kept 2 mm away from the human head voxel,
while each antenna element is excited with 25 mW. Figs.
10(a) and 10(b) depict the front, and side views of the SAR
field values averaged over the simulated-tissue human head
model at 3.9 GHz and 5.8 GHz, respectively. As the peak
SAR values are 0.41 w/kg and 0.33 w/kg at f1 (3.9 GHz) and
f2 (5.8 GHz), respectively, they are significantly lower than
the FCC permissible SAR limit (1.6 W/kg over 1 gram tissue)
[27].
wideband (covering up to 6 GHz and 7.125 GHz) designs for
5G mobile applications.
TABLE 1. PERFORMANCE COMPARISON WITH EXISTING DESIGNS
THAT COVER UP TO 6 GH Z AND 7.125 GH Z
Ref.
Profile
Profile
Isolation
ECC
PCCMIMO
(GHz)
(mm)
[16]
3.1-6*
7
10
0.1
398
[17]
3.27-5.92#
7
12
0.1
43.938
[18]
3.3-6*
6
11
0.12
408
[19]
3.3-7.1*
7
11
0.09
39.88
[20]
3.3-7.5*
7
11
0.05
NA
This
work
3.2-7.3*
6
12
0.069
42.78
Ref.: Reference, ECC: Envelope correlation coefficient, Pcc: Peak channel
capacity, *: 6 dB impedance bandwidth, #: 10 dB impedance bandwidth, Na:
Not available.
By observing the table, it is evident that the proposed MIMO
antenna covers the required 5G NR bands of interest (3.37.125 GHz) while maintaining good isolation levels of > 12
dB, ECC values of < 0.069, and peak channel capacity of up
to 42.7 bps/Hz. By observing [16]-[18], they have a profile of
7 mm and cannot cover the 5G NR band n96. Even though [19]
has realized the desired 5G NR bands of interest, it was
achieved by loading large dimension slots into the system
ground plane, which is not encouraged for practical mobile
applications. As for the one reported in [20], it is suitable only
for a 4 × 4 MIMO antenna array arrangement, thus failing to
fulfill the promise of high channel capacity requirement for
5G applications. In contrast, the proposed eight-element
MIMO antenna can cover from 3.2 to 7.3 GHz without
compromising another performance parameter. It also fulfills
sleek mobile phone demand with a profile of only 6 mm.
Furthermore, it has exhibited desirable isolation without
loading any additional decoupling element.
IV. CONCLUSION
FIGURE 15. SAR field at resonance frequencies (a) at 3.9 GHz (b) at 5.8 GHz.
An eight-element MIMO antenna has been successfully
verified. The proposed wideband MIMO antenna can cover
the entire 5G NR n77/n78/n79/n96, LTE 46, and WLAN 5
GHz bands with isolation greater than 12 dB. Besides
exhibiting a desirable ECC of less than 0.069, it has also
achieved a peak channel capacity of 42.7 bps/Hz. The SAR
study of the proposed MIMO antenna was carried out to
examine the interaction between the human head and the
designed MIMO array. The results have shown acceptable
average SAR values within the FCC permissible limit.
Therefore, the proposed MIMO antenna array is a good
candidate for a future slim 5G mobile terminal.
D. COMPARISON
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This article has been accepted for publication in IEEE Access. This is the author's version which has not been fully edited and
content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2022.3232698
ANJU KUMARI RAI received the B. Tech
degree in Electronics and Communication
Engineering from
University College of
Technology, Jharkhand, India, in 2016, and the M.
E. degree in Microwave Communication in the
year 2018 from the Birla Institute of Technology,
Mesra, India. Her thesis was on Filter design over
Folded Substrate Integrated
Waveguide.
Currently, she is pursuing a Doctor of Philosophy
(PhD) in RF & Microwaves discipline in the
Electrical Engineering department of the Indian
Institute of Technology (IIT) Kanpur, India. Her research interests include
MIMO antennas, 5G and beyond antennas.
RAHUL KUMAR JAISWAL received the B.
Tech degree in Electronics and Communication
Engineering from Uttar-Pradesh Technical
University, Lucknow, India, in the year 2012. He
worked as a Project Trainee in Society for
Applied Microwave Electronics Engineering and
Research (SAMEER) Kolkata in 2015-16. He has
completed his M. Tech degree in Microwave
Electronics in the year 2016 from the University
of Delhi South Campus, Delhi, India. He also
worked as a Scientist in Institute for Plasma
Research (IPR) Gandhinagar, India, in 2016-17.
Presently, he is pursuing a Doctor of Philosophy (PhD) in RF & Microwaves
discipline under the supervision of Prof. Kumar Vaibhav Srivastava in the
Electrical Engineering Department at the Indian Institute of Technology
Kanpur, India. Currently, he is serving as a Chair of IEEE APS-SBC at IIT
Kanpur, India. He has published several journal/conference papers on
various aspects of antennas and RF waveguides. He received IEEE
Antennas and Propagation Society Doctoral Research Grant in 2021. His
research interests include MIMO antennas, circularly polarized antennas,
unidirectional and bidirectional endfire CP antennas, base station antennas,
and full-duplex antennas.
KAHANI KUMARI received the B. Tech degree
in Electronics and Communication Engineering
from West Bengal University of Technology,
Kolkata, India, in 2012, and the M. E. degree in
Microwave Communication in the year 2015 from
the Indian Institute of Engineering Science and
Technology, Shibpur, India. Currently, she is
pursuing a Doctor of Philosophy (PhD) in RF &
Microwaves discipline in the Electrical Engineering
department of the Indian Institute of Technology
(IIT) Kanpur, India. She has published several journal/conference papers on
various aspects of full-duplex antennas and circularly polarized antennas.
Her research interests include full-duplex antennas, MIMO antennas,
circularly polarized antennas, unidirectional and bidirectional endfire CP
antennas and base station antennas.
KUMAR VAIBHAV SRIVASTAVA
received the B.Tech. degree in
Electronics Engineering from Kamla
Nehru Institute of Technology, Sultanpur,
India, in 2002, and the M.Tech. and Ph.D.
degrees both in Electrical Engineering
from Indian Institute of Technology
Kanpur, Kanpur, India, in 2004 and 2008,
respectively. He was with the GE Global
Research Centre, Bangalore, India, for
one year in 2008. In 2009, he joined as an
Assistant Professor with the Department of Electrical Engineering, IIT
Kanpur, where he is currently serving as a Professor since November 2018.
His extensive research interests are microwave antennas, metamaterials,
metamaterial absorbers and cloaking, FDTD technique, and MIMO
Antennas. He has published more than 115 international journal papers, two
international patents and 150 conference papers in the last fifteen years. Dr.
Srivastava received various national and best paper awards. He was
Chairperson of IEEE UP Section in 2018 and founding Chair of IEEE
Antenna and Propagation Society Chapter in UP Section.
CHOW-YEN-DESMOND SIM (M’07–
SM’13) was born in Singapore in 1971. He
received the B.Sc. degree from the Engineering
Department, University of Leicester, U.K., in
1998, and the Ph.D. degree from the Radio
System Group, Engineering Department,
University of Leicester, in 2003. From 2003 to
2007, he was an Assistant Professor with the
Department of Computer and Communication
Engineering, Chienkuo Technology University,
Changhua, Taiwan. In 2007, he joined the
Department of Electrical Engineering, Feng
Chia University (FCU), Taichung, Taiwan, as an Associate Professor, where
he became a Full Professor in 2012 and as a Distinguish Professor in 2017.
He has served as the Executive Officer of Master’s Program with the
College of Information and Electrical Engineering (Industrial Research and
Development), the Director of Intelligent IoT Industrial Ph.D. Program
between August 2015 and July 2018. He co-founded the Antennas and
Microwave Circuits Innovation Research Center in Feng Chia University
and served as the Director between 2016 and 2019. He has served as the
Head of Department of Electrical Engineering in Feng Chia University
between 08/2018 and 07/2021. He has authored or coauthored over 170 SCI
papers. His current research interests include antenna design, VHF/UHF
tropospheric propagation, and RFID applications. He is a Fellow of the
Institute of Engineering and Technology (FIET), a Senior Member of the
IEEE Antennas and Propagation Society, and a Life Member of the IAET.
He has served as the TPC Member of many international conferences, and
has also served as the TPC Sub-Committee Chair (Antenna) of the ISAP
2014 and PIERS 2017/2019. He was invited as the Workshop/Tutorial
Speaker in APEMC 2015, iAIM 2017, InCAP 2018, and the Invited Speaker
of TDAT 2015, iWAT 2018, APCAP 2018, ISAP 2019, InCAP 2019,
ISRAST 2020, and URSI GASS 2021. He was the Keynote Speaker of SOLI
2018, ISRAST 2020, and NEAST 2020. He has served as the Advisory
Committee of InCAP 2018/2019 and ICoICCS 2021, and has also served as
the TPC Chair of the APCAP 2016, iWEM 2019/2020. He is now serving
as the General Co-Chair of ISAP 2021. He has served as the Chapter Chair
of the IEEE AP-Society, Taipei Chapter (from 01/2016 to 12/2017), and he
is the founding Chapter Chair of the IEEE Council of RFID, Taipei Chapter
(from 10/2017 to 12/2020). He has served as the AE of IEEE Access
between 08/2016 and 01/2021. He is now serving as the Associate Editor of
IEEE AWPL, IEEE Journal of RFID, and (Wiley) International Journal of
RF and Microwave Computer-Aided Engineering. Since October 2016, he
has been serving as the technical consultant of SAG (Securitag Assembly
Group), which is one of the largest RFID tag manufacturers in Taiwan. He
is also serving as the consultant of Avary (the largest PCB manufacturer in
mainland China) since August 2018. He was the recipient of the IEEE
Antennas and Propagation Society Outstanding Reviewer Award (IEEE
Transaction Antennas and Propagation) for seven consecutive years
between 2014 and 2020. He has also received the Outstanding Associate
Editor Award from the IEEE Antennas Wireless and Propagation Letters in
July 2018.
8
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