Integrated Narrow Band (NB) and UWB MIMO Antenna for IoT Applications

Abstract

In this work, we have integrated narrow band (NB) and Ultra-Wide Band (UWB) four-port MIMO antennas designed and implemented in IoT applications. The designed antenna consists of two quarter-wavelength asymmetrical NB radiators and a reverse P-shaped UWB radiator. The two NBs are generated by two quarter-wavelength non-identical radiators, and the UWB is generated by a semi-circle-shaped monopole radiator. Further, the NB radiators and UWB radiators are connected in a 3-mm-wide feed line. The antenna is designed to operate at 1.8 GHz (3G), 2.4 GHz (WLAN), and 3.1–12 GHz (UWB) for IoT applications. In this designed four-port MIMO antenna, two proposed NB and UWB radiators are mounted on the front side of the FR4 substrate and the other two on the rear side of the FR4 substrate. The proposed MIMO antenna has a dimension of 65×65×1.6mm3. The antenna performance and MIMO performance are analyzed. The diversity metrics such as ECC, DG, TARC, MEG, and CCL are computed, and their values are 0.26, 9.87 dB, −22 dB, −6 dB, and 0.27 bits/Hz/s, respectively, within the bounds. The real-time implementation of the designed antenna is demonstrated at 2.4 GHz for smart home applications.

Full text

Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=tijr20
IETE Journal of Research
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tijr20
Integrated Narrow Band (NB) and UWB MIMO
Antenna for IoT Applications
Saminathan Thiruvenkadam & Eswaran Parthasarathy
To cite this article: Saminathan Thiruvenkadam & Eswaran Parthasarathy (2023): Integrated
Narrow Band (NB) and UWB MIMO Antenna for IoT Applications, IETE Journal of Research, DOI:
10.1080/03772063.2023.2196260
To link to this article: https://doi.org/10.1080/03772063.2023.2196260
Published online: 09 Apr 2023.
Submit your article to this journal
View related articles
View Crossmark data

IETE JOURNAL OF RESEARCH
https://doi.org/10.1080/03772063.2023.2196260
Integrated Narrow Band (NB) and UWB MIMO Antenna for IoT Applications
Saminathan Thiruvenkadam and Eswaran Parthasarathy
Department of ECE, SRM Institute of Science and Technology, Kattankulathur, Chennai, India
ABSTRACT
In this work, we have integrated narrow band (NB) and Ultra-Wide Band (UWB) four-port MIMO
antennas designed and implemented in IoT applications. The designed antenna consists of two
quarter-wavelength asymmetrical NB radiators and a reverse P-shaped UWB radiator. The two NBs
are generated by two quarter-wavelength non-identical radiators, and the UWB is generated by a
semi-circle-shaped monopole radiator. Further, the NB radiators and UWB radiators are connected
in a 3-mm-wide feed line. The antenna is designed to operate at 1.8 GHz (3G), 2.4GHz (WLAN), and
3.1–12 GHz (UWB) for IoT applications. In this designed four-port MIMO antenna, two proposed NB
and UWB radiators are mounted on the front side of the FR4 substrate and the other two on the
rear side of the FR4 substrate. The proposed MIMO antenna has a dimension of 65 ×65 ×1.6 mm3.
The antenna performance and MIMO performance are analyzed. The diversity metrics such as
ECC, DG, TARC, MEG, and CCL are computed, and their values are 0.26, 9.87 dB, −22 dB, −6 dB,
and 0.27 bits/Hz/s, respectively, within the bounds. The real-time implementation of the designed
antenna is demonstrated at 2.4 GHz for smart home applications.
KEYWORDS
3G; IoT; MIMO; NB; UWB;
WLAN
1. INTRODUCTION
In recent days, there is a rapid development in modern
communication systems such as mobile phones, home
appliances, industrial equipment, and so on, due to
the incorporation of Internet of Things (IoT) technol-
ogy. Physical sensing equipment can now be controlled
remotely using this technology. These devices must be
portable, less expensive, and power-ecient to func-
tion on multi-band antenna systems for GSM, 3G, LTE,
WLAN, WiMax, 5G, and other wireless technologies.
This trend will improve with the growing demand for
portable devices and a better antenna unit. The miniatur-
ization of embedded systems allows many modules to be
assembled in dierent situations, such as environmental
monitoring, smart-city, intelligent medicine, smart-grid,
military applications, and so on, to improve eciency
and reliability [1,2]. The antenna module, which is the
front end of any portable communication device, cov-
ers most essential frequency bands, including 800 MHz
(GSM), 1.8 GHz (3G), 2.3 GHz (4G), 2.4 GHz (WLAN),
2.6 GHz (LTE), 3.3 GHz (5G), 3.5 GHz (WiMax), 5 GHz,
5.5 GHz, and 3–11 GHz (UWB) [3] with good radiation
characteristics for various applications. Furthermore,
current antenna design is expected to be versatile enough
to modulate impedance bandwidth autonomously for
multiple center frequencies [4]. In addition, MIMO
techniques are used to deliver high data rates and link
reliability for the antenna module of an IoT device
without requiring an increase in additional spectrum
orIII power [5].VariousNarrowBand(NB)[6–15], UWB
MIMO antenna [16–20], re-congurable NB, and UWB
MIMO antenna [21] are implemented and reported in
the literature survey. The NB-based antenna designs are
commonly used a miniature radiator in the shape of
aYwithatwinringresonator[6], a Y-shaped radia-
torwithagroundplaneslitcarvedoutforanL-shaped
slit [7], a step-shaped microstrip feed line used to
load a rectangular patch’s two asymmetrical folding slots
[8], a λ/4 wavelength of two non-identical L and T
shaped radiators placed with micro strip [9], the T-
shape has an etched open slot in the ground [10], two
C-slots and two symmetrical E-slots are removed from
the ground plane by a rectangular patch [11], Strips with
several branches [12], and two parallel stripes [13]
have been presented for LTE/WWAN/WiMAX/WLAN
applications. A printed two asymmetrical inverted L-
shaped loaded with micro strip fed patch antenna [14],
meander lines based monopole antenna [15]arepro-
posed for UMTS/GNSS/LTE/WLAN/WiMAX/INSAT-C
applications. A two-port UWB MIMO antenna is real-
ized to achieve 3–11 GHz bandwidth in [16]. Using
four UWB MIMO radiators, the impedance bandwidth is
2–12 GHz, and mutual coupling is less than −20 dB using
an orthogonal arrangement [17]. Four half-circle-shaped
UWB radiators were employed to produce 3–12 GHz
bandwidth and mutual coupling of less than −20 dB
© 2023 IETE

2 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
using orthogonal positioning [18]. In [19], impedance
bandwidth of 3–12 GHz realized using SIW method and
orthogonal placement approach is used to realize less
than −20 mutual coupling. In [20], impedance band-
widthof3–12GHzandNBisrealizedusingatriangular-
shaped radiator with a re-congurable mechanism and
an orthogonal placement approach is used to realize less
than −20 mutual coupling. A re-congurable antenna is
implemented for both UWB and NB applications with
metamaterial, Split Rings Resonator (SRR), and -shape
strip [21]. Furthermore, various techniques are used to
minimize mutual coupling between the radiators, includ-
ing orthogonal positioning, awed grounding, neutraliz-
ing, and metamaterials [16–21].
As reported in the literature survey dierent UWB
MIMIO antenna, recongurable antenna and NB MIMO
antennas were implemented for various applications, but
they are all either NB or UWB antenna. To achieve
both NB and UWB functions in single MIMO antenna,
there is a need for an integrated NB and UWB MIMO
antenna for IoT applications along with important design
parameters, i.e. compact size, better radiation charac-
teristics, etc. Hence, in this work an integrated NB and
UWB antenna is introduced in the proposed antenna
to reduce the mutual coupling between radiators using
double-sided placement techniques. The designed four-
port MIMO antenna, two proposed NB and UWB radia-
tors are mounted on the front side of the FR4 board and
the other two on the rear side of the board. The proposed
MIMO antenna has a size of 65 ×65 ×1.6 mm3.
SalientfeaturesofproposedDNBandUWBMIMO
antenna are:
•The designed MIMO antenna operates at 3G
(1.7–1.83 GHz), WLAN (2.3–2.44GHz), and it covers
UWB (3.1–12 GHz) for IoT applications.
•The mutual coupling among the ports of the designed
antenna is <−20 dB without a decoupling structure.
•The diversity metrics such as ECC, DG, TARC, MEG
and CCL of proposed antenna is analyzed through
experiments.
•The proposed antenna performance was analyzed for
smart home applications at 2.4 GHz.
Thispaperisorganizedasfollows.Theunitelementand
MIMO antenna design were analyzed in Section 2.The
experimental measurement and validation were carried
out in Section 3,followedbyconcludingremarks.
Figure 1: Development of the designed unit cell
Tab le 1: Dimension of the integrated NB and UWB radiators
Dimensions Value (mm) Dimensions Value (mm)
L32L
78
W15L
s5.5
Lf11 Lg8
L15.5 Wf3
L219 Ws3.5
L32.5 Wg15
L48W
11.5
L56G
10.5
L69.5 G22
2. DESIGN OF NB AND UWB RADIATORS
ThissectionhascoveredNBandUWBunitelement
designs, surface current distribution of NB and UWB
antennas at operating bands, and the four-port MIMO
antenna design.
2.1 NB Antenna Design
The dimension of the designed NB and UWB antenna
is presented in Figure 1. The front side of the substrate
seems to comprise two quarter-wavelength asymmetrical
NB radiators and a reverse P-shaped UWB radiator with
a 50-ohm microstrip feed. A slotted ground plane that
has been optimized is located on the substrate’s reverse.
The unit cell has a conductor that is 0.035mm thick and
is built on a FR4 substrate that is 1.6 mm thick. Table 1
shows the optimized dimensions for the designed unit
cell, which has a total size of 32 ×15 mm2.
The four-port integrated NB and UWB antenna design
processbeginswithanNBradiatordesign.Theproposed

S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS 3
Figure 2: Evolution of the designed unit cell (a) Antenna-1, (b) Antenna-2, (c) Antenna-3, (d) Antenna-4
dual narrow band (DNB) antenna comprised of two λ/4
wavelength NB radiating stubs and a rectangular ground
plane. The evolution of the NB antenna is illustrated in
Figure 2(a–b).
2.1.1 Antenna-1
Aλ/4 wavelength complementary L-shaped radiator-1, a
feed line 3 mm wide, and a partial ground plane comprise
the antenna-1 illustrated in Figure 2(a).
The length of the proposed complementary L-shaped
stub and resonant frequency (fr1)iscalculatedusing
Equations (1), (2) and (3).
fri =C
4Lsj√εe
i,j=1, 2 (1)
εe =εr+1
2(2)
where fri is ith resonance and εe istheeectivedielectric
constant.
LS1=L1+L2+W1=λg
4≈30 mm (3)
where LS1is the length of the complementary L-shaped
stub, L1,L
2and W1are parameters of the complementary
L-shaped stub. The length of the L-shaped stub (Ls1) is
Figure 3: Reflection coefficient of proposed NB antenna
determined by calculating the length and width of the Ls1
asdescribedinEquation(3),anditisabout30mm [22].
Theoretically, the operating frequency fr1 of antenna-
1 is 2.4 GHz, but the simulated resonating frequency is
2.5 GHz, as shown in Figure 3. This is a small dierence
of 4% from the theoretical value. It is perceived that the
Antenna-1 reection coecient is <−10 dB at 2.5 GHz.

4 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
Figure 4: Simulated electric field distribution of the designed NB
radiator and UWB radiator at (a) 1.8 GHz, (b) 2.4 GHz, (c) 3.4 GHz
Figure 5: Reflection coefficients of the proposed unit cell
2.1.2 Antenna-2
Similarly, antenna-1 is coupled to a second-quarter wave-
length seven-shaped radiator-2. As shown in Figure 2(b),
Figure 7: S-parameters (Simulated) of proposed MIMO antenna
Antenna-2 consists of a pair of L-shaped, seven-shaped
radiators coupled by a 3-mm-wide feed line and a par-
tial ground plane. The length of the proposed seven-
shaped stub and resonant frequency (fr2)iscalculated
using Equations (1), (2) and (4) at 1.8 GHz.
LS2=L2+L3+L4+L5+G2=λg
4≈40 mm (4)
where LS2is length of the seven-shaped stub, L2,L
3,L
4,
L5,andG
1are the parameters of the seven-shaped stub.
The length of the inverted 7-shaped stub (LS2) is approx-
imated at 40 mm using the length and width of the LS2 as
described in Equation (4) [22]. Further, the Antenna-2
distance between radiators is adjusted to ensure mini-
mal coupling between them, as shown in Figure 2(b).
Due to this loading of seven-shaped stub, along with
complementary L-shaped stub the Antenna-2 generates
the resonant frequencies at 1.85GHz and 2.4 GHz as
depicted in Figure 3.Itcanbeobservedthatdueto
Figure 6: Proposed double-sided integrated NB and UWB MIMO antenna

S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS 5
Figure 8: Simulated electric field distribution of designed at
1.8 GHz (Port 1–Port 4 excitation)
seven-shaped the new resonance frequency generate that
is slight variation of 2.7 % between theoretical resonant
frequency (1.8 GHz) and simulated resonant frequency
(1.85 GHz). The designed DNB radiator is suitable for
the 3G and WLAN applications. The current distribution
for the dual-band is presented in Figure 4(a–b) to eec-
tively depict the antenna’s resonance. Figure 4(a) depicts
the current distribution at the rst resonance (1.8 GHz).
Maximum current density is available in the radiator-2
at 1.8 GHz, as can be shown in Figure 4(a). Figure 4(b)
depicts the current distribution at the second resonance.
At 2.4 GHz, it can be seen that the radiator-1 has the high-
est current density. Hence, the current distribution shows
that the antenna functions independently.
2.2 Design of UWB Radiator
The proposed antenna has UWB characteristics along
with dual-band NB characteristics. To achieve both NB
and UWB characteristics in the proposed radiator, the
UWB radiator is connected with an Antenna-2. Initially,
acircularradiatorisusedintheantennadesigntoachieve
UWB characteristics, as shown in Figure 2(c). But the
size is of the circular radiator is not suitable to inte-
grate with the proposed dual-band NB radiator. Also, as
illustrated in Figure 5the Antenna-3 circular radiator is
not having impedance bandwidth from (3.1–10.6)GHz.
The Antenna-4 to integrate the UWB radiator with the
proposed DNB radiator and improve the impedance
bandwidth, the three quarters are removed from the full
circle among the four quarters of the circular radiator,
which generates the P-shaped UWB radiator (Radiator-
3) as depicted in Figure 2(d) and reection coecient
depicted Figure 5. Furthermore, as shown in Figure
2(d), a rectangular slit is cut out of the ground plane to
match impedance. In a P-shaped radiator, current ows
along the boundary, which helps to achieve impedance
matching after the circular radiator has been modied
as illustrated in Figure 4(c). As a result, the size reduc-
tion and integration are achieved without compromising
performance features such as UWB bandwidth and other
radiation characteristics. The following expression can be
used to estimate the circular radiator’s lowest resonant
frequency.
fr=c
λ=150
2×(π×b)g+w=3.1 GHz (5)
where g-distance from the base of the radiator to the
ground, b-P-shaped radiator radius, w is height of the
UWB radiator. The design of UWB radiator at lowest fre-
quency (3.1 GHz) calculated using Equation (5) while the
simulatedlowestfrequencystartat3GHzasillustrated
Figure 5, which is slight variation of 4% to theoretical
Figure 9: Photo of fabricated designed MIMO antenna and VNA measurement setup

6 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
value. Finally, after the integration of the proposed P-
shaped UWB radiator with dual-band NB radiators the
proposed integrated NB and UWB antenna resonates at
1.8 GHz, 2.4 GHz, and 3–11 GHz with less than −10 dB
reection coecient is presented in Figure 5.
2.3 Design Procedure of the Proposed Integrated
NB and UWB MIMO Antenna
The designed double-sided integrated NB and UWB
MIMOantennaisconstructedbyplacingfourintegrated
NB and UWB radiators on both sides of the substrate, as
shown in Figure 6. The front side of the substrate appears
to have two radiators printed on it, while the back side
appears to have two radiators printed with the appro-
priate ground plane positioned on the opposite side of
the substrate. The designed four-port MIMO antenna is
printed on a 1.6-mm-thick FR4 substrate and simulated
using a CST microwave studio. The double-sided orthog-
onal placement is used to provide an absorber that limits
thedistributionofcurrentontheradiatingelementand
the mutual coupling of the antennas at the operating fre-
quencies by rejecting the surface wave eld without a
decoupling mechanism [23]. In addition, the designed
antenna radiators are orthogonal placement provides
polarization diversity, which strengthens link reliabil-
ity. The size of the designed four-port MIMO antenna
is 65 ×65 mm2and the antenna is operating with <
−10 dB reection coecient at 1.8 (1.75–1.86 GHz), 2.4
(2.32–2.44 GHz), and 3.1–11 GHz (UWB) as depicted in
Figure 7. Besides, the proposed antenna has less than
−15 dB mutual coupling at 1.8 GHz, 2.4, and 3.1–11 GHz
(UWB) between the radiators as presented in Figure 7.
Thesurfacecurrentdistributionat1.8GHzisshownin
Figure 8(a–d) for a better understanding of mutual cou-
pling reduction due to the double side and orthogonal
placement in the proposed antenna while port-1 to port-
4areexcited.Itisperceivedthatwhenport-1toport-4is
activated, there is no coupling current at other ports.
3. RESULTS AND DISCUSSIONS OF PROPOSED
MIMO ANTENNA
This section deals with the measured S-parameters, radi-
ation pattern, gain, and eciency of proposed antenna.
Additionally, MIMO parametric analysis and real time
validation is discussed in this section.
3.1 Reflection Coefficient and Mutual Coupling
The designed four-port MIMO antenna is fabricated
using FR4 substrate and it is presented in Figure 9and
Figure 10: Measured reflection coefficients and mutual coupling
of proposed integrated NB and UWB MIMO antenna
Figure 11: The designed antenna unit under test in anechoic
chamber
the antenna is measured using Vector Network Ana-
lyzer after fabrication. The measured S-parameter (S11)
is depicted in Figure 10.Itisevidencethatthepro-
posed MIMO antenna has less than −10 dB reection
coecient at 1.8 (1.7–1.83 GHz), 2.4 (2.3–2.44 GHz), and
3.1–12 GHz. It is suitable for 3G, WLAN, and UWB
applications. Likewise, the measured mutual coupling
(S12,S
13,S
14)isdepictedinFigure10.Itisobservedthat

S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS 7
Figure 12: Radiation pattern of the designed MIMO antenna
the designed antenna has less than −20 dB mutual cou-
pling at 1.8, 2.4, and 3–12GHz. It is understood, from
the measured results, the proposed antenna performs
well after fabrication. Hence, the proposed integrated NB
and UWB MIMO antenna is suitable for NB and UWB
MIMO applications.
3.2 Radiation Characteristics
The proposed four-port MIMO antenna radiation char-
acteristics are measured using an anechoic chamber
as illustrated in Figure 11.Figure12 depicts simu-
lated and measured E-plane (X–Z) and H-plane (Y–Z)
co-polarization and cross-polarization radiation pat-
terns at 1.8, 2.4, 3.4, and 10.5 GHz. It is witnessed
of that the designed antenna exhibits a nearly omni-
directional radiation pattern at both the NB (1.8 and
2.4 GHz) and UWB (3.1–12 GHz) frequencies. Due to
these characteristics, the proposed antenna eectively
transmits and receives in all directions, which improves
the link reliability of the designed antenna [24]. Hence,
it is suitable for the NB and UWB MIMO antenna-based
IoT applications.
3.3 Gain and Efficiency
Figure 13 illustrates the simulated and measured gain and
total eciency of the designed antenna at port 1 from the
Figure 13: Gain and total efficiency of the proposed MIMO
antenna
far-eld distance[>2D2
λ]. It is observed that the designed
antenna has a gain of 1.25 dBi, 1.5 dBi, and 1.75–4.25 dBi
at 1.8 GHz, 2.4 GHz, and 3.1–12GHz respectively. The
proposed 4-port MIMO antenna has a total eciency of
72 %, 75%, and 72–85% at 1.8 GHz, 2.4 GHz, and 3.1-
12 GHz respectively. Therefore, the proposed antenna
achieves an overall peak gain >1.25 dbi and total e-
ciency >72% in the operating bands and it is presented
in Figure 13.

8 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
Figure 14: ECC of proposed MIMO antenna
3.4 Diversity Metrics of Designed Antenna
In this section, the S-parameters, and radiation pattern
are computed and measured values that are used to
analyze the important diversity metrics for the designed
MIMO antenna.
3.4.1 ECC
Envelope Correlation Coecient (ECC) is another essen-
tial indicator to assess MIMO performance because it
represents the amount of decoupling between radiators.
TheabsolutevalueofECCis0.Evenso,real-timeECC
should be less than 0.5 [22,25]. Equation (6) can be used
to assess ECC from the far eld.
ECC =[−→
Sa(θ,φ).−→
Sb(θ,φ)]d
2
[−→
Sa(θ,φ)]
2d−→
Sb(θ,φ)]
2d
(6)
where d,ϕ,andθare the respective beam area,
azimuthal and elevation, and S is radiated electric eld
pattern. The proposed antenna has an ECC of less than
0.26 at the resonating bands, as illustrated in Figure 14.
3.4.2 DG
Diversity techniques are adopted to create MIMO anten-
nas.Asaresult,whenmorethanoneradiatoris
employed, diversity gain (DG) is achieved. The proposed
antenna’s DG can be calculated from the Equation (7).
DG =101−ECC2(7)
Figure 15 shows the designed MIMO antenna character-
istics and the DG >9.87 dB obtained at the operating
bands.
Figure 15: DG of designed MIMO antenna
Figure 16: TARC of proposed MIMO antenna
3.4.3 TARC
The TARC is a key parameter for accurately estimat-
ing the mutual coupling among MIMO antenna ports.
Equation (8) can be used to estimate the TRAC value for
two-port MIMO antennas [26].InidealcaseTRACvalue
must be <0dB.
TARC =(S11 +S12 ejθ)2+(S21 +S22ejθ)2
2
Where, θliesfrom0to2π
(8)
The designed antenna has less than −22 dB TARC value
at the resonating bands, as illustrated in Figure 16.
3.4.4 CCL
The Channel Capacity Loss (CCL) determines the high-
est boundary beyond which information communication

S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS 9
Tab le 2: MEG of designed NB and UWB MIMO antenna
Frequency
(GHz) MEG-1 MEG-2 MEG-3 MEG-4
MEG-1/
MEG-2
MEG-3/
MEG-4
1.8 −8.44 −8.53 −8.42 −8.51 0.989 0.989
2.4 −6.76 −6.93 −6.86 −6.84 0.975 1.002
3.4 −6.73 −6.95 −6.85 −6.86 0.966 0.998
5.4 −6.37 −6.36 −6.35 −6.36 1.001 0.998
10.5 −6.19 −6.11 −6.12 −6.11 1.013 1.001
can occur without causing any loss in the transmission
channel. CCL ranges that are acceptable must be less
than 0.4 bits/sec/Hz [27,28]. Equations (9) and (10) can
be used to estimate the CCL value for two-port MIMO
antennas.
CCL =−log2det ψR(9)
ψR=
φ11 φ12
φ21 φ22
(10)
where ψRis the receiving antenna correlation. The
designed antenna has less than 0.27 bits/Hz/Sec CCL
value at the resonating bands, as illustrated in Figure 17.
3.4.5 MEG
Mean Eective Gain (MEG) is a signicant factor to
consider when analyzing the performance of a MIMO
antenna. In a fading environment, it is calculated by com-
paring the average energy received by the diverse antenna
to the average energy received by an isotropic antenna.
Equation (11) is used to obtain the MEG-1, MEG-2,
MEG-3, and MEG-4 values that are close to the standard
range (−3≤MEG (dB) <−12) as shown in Table 2[22].
Furthermore, the MEG1/MEG2 and MEG3/MEG4 ratios
areneartoone,whichisrequiredbyamultipathfading
standard.
MEGi=0.5 ⎛
⎝1−
N

j=1Sij
2⎞
⎠(11)
Figure 17: CCL of proposed MIMO antenna
3.4.6 Comparison of NB and UWB Antenna and MIMO
Antenna
The designed antenna parameters are compared with
existing antennas and are given in Table 3.
4. REAL-TIME IMPLEMENTATION OF DESIGNED
NB AND UWB MIMO ANTENNA
In this section we discuss the real-time validation of
proposed antenna NB- and UWB-based application.
4.1 NB- Based Smart Home Application at 2.4 GHz
The block diagram of real-time NB based home automa-
tion application implementation is carried out using the
proposed MIMO antenna, CC2538 kit (ZigBee Mod-
ule), dierent types of sensors, serial port monitor, and
IoT 2040 gateways as illustrated in Figure 18.Thepro-
posed antenna is used to for the transmission antenna
and for reception purpose. The LDR sensor, magnetic
Tab le 3: Comparison of proposed NB and UWB antenna and existing antennas MIMO
Refs.
Operating
bands
Antenna
size (L ×W
in mm2)
Operating
band (GHz)
Mutual
coupling
dB ECC
[6] Tri-band 30 ×24 2.5–2.7, 3.3–3.6, 5.2–5.8 – –
[7] Tri-band 75 ×120 0.9, 1.85, 2.4 – –
[9] Tri-band 45 ×10 2.3–2.69, 3.4–3.7, 5.15–5.85 – –
[11] Quad-band 70 ×50 1.43–1.6, 1.94–2.1, 2.42–2.57, 3.45–3.64 – –
[12] Quad-band 40 ×40 2.47–2.54, 4.14–4.23, 5.43–5.78, 6.71–7.42
[16] UWB 94.2 ×94.2 3–11 <−15 <0.005
[17] UWB 94 ×94 2–12 <−20 –
[18] UWB 40 ×40 3–14 <−17 <0.05
[19] UWB 40 ×40 2–14 <−19 –
[20] UWB 120 ×60 1–5 <−15 <0.5
[21] Single- band & UWB 40 ×40 3.1–10.6 – –
&1.7
Proposed Dual-band & UWB 65 ×65 3G (1.7–1.83 GHz), WLAN (2.3–2.44 GH z), <−20 <0.26
& UWB (3.1–12 GHz)

10 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
Figure 18: Block diagrams of the smarthome application using proposed antenna
Figure 19: Snapshot of real-time IoT-based home automation implementation using proposed antenna: (a) sensors, proposed antenna,
and IoT gate way; (b) received sensor data in serial port monitor, (c) stored in sensor data in Think speaker cloud
sensor, temperature sensor, and humidity sensor are con-
nected with CC2538 kit (Zigbee Module-1) as show
in Figure 19(a). It is observed that the four sensors
dataaretransmittedusingproposedantennawhichcon-
nected with CC2538 kit (Zigbee Module-1). Further, the
four sensor data are received using proposed antenna
which connected with CC2538 kit (Zigbee Module-2).
Additionally, the received sensor’s data are connected
with cloud through IoT 2040 gateway to access the data
remotely from multiple devices from anywhere. The
received sensor data is stored in the think speak cloud
through the IoT 2040 gateway and captured image shown
in Figure 19(c). In order to visualize the sensor’s data
locally the serial port monitor is connected to CC2538
kit (Zigbee Module-2) as depicted in Figure 19(b). The
realtimeserialportmonitorsnapshotforthereceived
sensor’s data is illustrated in Figure 19(b). Hence, the pro-
posed MIMO antenna implemented in NB based smart
home applications and the performance was analyzed at
2.4 GHz.
5. CONCLUSION
A four-port integrated NB and UWB MIMO antenna
is designed, fabricated, and tested for IoT applications.
The two NBs are generated by two quarter- wavelength
non- identical radiators and UWB is generated by a semi-
circle shaped monopole radiator. The designed antenna
operates at 1.8 GHz (3G), 2.4 GHz (WLAN), and it cov-
ers 3.1–12 GHz (UWB) for IoT applications. Impor-
tant antenna characteristics, including S11 of <−10 dB,

S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS 11
mutual coupling of <−20 dB between ports, peak gain
of >1.25 dBi, nearly omnidirectional radiation pattern,
and total eciency of >72%, are experimentally deter-
mined in the operating bands. The diversity metrics ECC,
DG, TARC, CCL, and MEG have been examined exper-
imentally and proven to be within acceptable parame-
ters. The performance of the developed MIMO antenna
isbettertoearlierstudies.Inaddition,wehaveshown
the antenna’s use in real-time applications. Hence, the
designed antenna can also connect sensor modules in an
IoT network.
DISCLOSURE STATEMENT
No potential conict of interest was reported by the author(s).
ORCID
Saminathan Thiruvenkadam http://orcid.org/0000-0002-
4733-0010
REFERENCES
1. D. P. Acharjya, and M. K. Geetha, “Internet of Things:
Novel Advances and Envisioned Applications,” in Inter-
net of Things: Novel Advances and Envisioned Applications,
2017.
2. S. C. Mukhopadhyay, and N. K. Suryadevara, “Internet of
things: Challenges and opportunities,” Smart Sensors,Vol.
9, pp. 1–17, 2014.
3. “RevisionofPart15oftheCommission’sRulesRegarding
UltraWide-Band Transmission Systems First Report and
Order, document,” in FCC 02.V48, 2002.
4. G. J. Jo, S. M. Mun, D. S. Im, G. R. Kim, Y. G. Choi,
andJ.H.Yoon,“NoveldesignofaCPW-FEDmonopole
Antenna with three arc-shaped strips for WLAN/WiMAX
operations,” Microw.Opt.Technol.Lett.,Vol.57,no.2,
pp. 268–273, 2015.DOI:10.1002/mop.28829
5. V. Kuhn, Wireless communications over MIMO channels:
applications to CDMA and multiple antenna systems.John
Wiley&Sons,2006.
6. G. Liu, Y. Liu, and S. Gong, “Compact tri-band wide-
slot monopole Antenna with dual-ring resonator for
WLAN/WiMAX applications,” Microw. Opt. Technol.
Lett., Vol. 58, no. 5, pp. 1097–1101, 2016.DOI:10.1002/
mop.v58.5
7.R.S.Brar,K.Saurav,D.Sarkar,andK.V.Srivastava,
“A triple band circular polarized monopole Antenna for
GNSS/UMTS/LTE,” Microw.Opt.Technol.Lett., Vol. 59,
no. 2, pp. 298–304, 2017.DOI:10.1002/mop.v59.2
8. A. R. Jalali, J. Ahamdi-Shokouh, and S. R. Emadian, “Com-
pact Multiband Monopole Antenna for UMTS, WiMAX,
and WLAN Applications,” 2016.
9. A. Kuma r, D. J hanwar, and M. M . Sha rma, “ A com -
pact printed multistubs loaded resonator rectangular
monopole Antenna design for multiband wireless sys-
tems,” Int. J. RF Microw. Comput. Aided Eng., Vol. 27, no.
9, pp. e21147–e21147, 2017.DOI:10.1002/mmce.v27.9
10. J.-Y. Deng, “Multiband Antenna for mobile terminals,” Int.
J. RF Microw. Comput. Aided Eng., Vol. 29,
pp. 21925–21925, 2019.
11. Chandan. M, “, “Truncated ground plane multiband
monopole antenna for WLAN and WiMAX applications,”
IETE.J.Res., Vol. 68, no. 4, pp. 1–6, 2020.
12. M.-A. Chung, “A miniaturized triple band monopole
Antennawithacoupledbranchstripforbandwidth
enhancement for IoT applications,” Microw. Opt. Tech-
nol. Lett., Vol. 60, no. 9, pp. 2336–2342, 2018.DOI:
10.1002/mop.v60.9
13. A. Chen, “Planar monopole antenna with a parasitic
shorted strip for multistandard handheld terminals,”
IEEE. Access., Vol. 8, pp. 51647–51652, 2020.DOI:
10.1109/Access.6287639
14. R. S. Brar, K. Saurav, D. Sarkar, and K. V. Srivas-
tava, “A quad-band dual-polarized monopole Antenna
for GNSS/UMTS/WLAN/WiMAX applications,” Microw.
Opt. Technol. Lett., Vol. 60, no. 3, pp. 538–545, 2018.DOI:
10.1002/mop.31008
15. R. Patel, T. Upadhyaya, A. Desai, and M. Palandoken, “Low
prole multiband meander antenna for LTE/WiMAX/
WLAN and INSAT-C application,” AEU – Int. J. Electron.
Commun., Vol. 102, pp. 90–98, 2019.DOI:10.1016/j.aeue.
2019.02.010
16. Y. Nie, X. Q. Lin, Z. Q. Yang, J. Zhang, and B. Wang,
“Structure-Shared planar UWB MIMO Antenna with high
isolation for mobile platform,” IEEE. Trans. Antennas.
Propag, Vol. 67, pp. 2735–2738, 2019.DOI:10.1109/
TAP.8
17.W.Youcheng,Y.Yanjiao,C.Qingxi,andP.Hucheng,
“Design of a compact ultra-wideband MIMO Antenna,”
J. Eng., Vol. 2019, no. 20, pp. 6487–6489, 2019.DOI:
10.1049/tje2.v2019.20
18. A. A. R. Saad, and H. A. Mohamed, “Conceptual design of
a compact four-element UWB MIMO slot Antenna array,”
IET Microw. Antennas Propag., Vol. 13, no. 2, pp. 208–215,
2019.DOI:10.1049/mia2.v13.2
19. A. A. R. Saad, “Approach for improving inter-element
isolation of orthogonally polarised MIMO slot Antenna
over ultra-wide bandwidth,” Electron. Lett, Vol. 54, no. 18,
pp. 1062–1064, 2018.DOI:10.1049/ell2.v54.18
20. X. Zhao, S. Riaz, and S. Geng, “A recongurable MIMO/
UWB MIMO antenna for cognitive radio applications,”
IEEE. Access., Vol. 7, pp. 46739–46747, 2019.DOI:
10.1109/Access.6287639

12 S. THIRUVENKADAM AND E. PARTHASARATHY: INTEGRATED NB AND UWB MIMO ANTENNA FOR IOT APPLICATIONS
21. S. Heydari, K. Pedram, Z. Ahmed, and F. B. Zarrabi, “Dual
band monopole Antenna based on metamaterial struc-
ture with narrowband and UWB resonances with recon-
gurable quality,” AEU Int. J. Electron. Commun., Vol. 81,
pp. 92–98, 2017.DOI:10.1016/j.aeue.2017.07.015
22. S. Thiruvenkadam, and E. Parthasarathy, “Design and
analysis of dual narrow band MIMO (DNB-MIMO)
antenna for IoT applications,” Appl. Comput. Electromag.
Soc. J. (ACES), Vol. 37, no. 8, pp. 901–911, 2022.
23. P. Palanisamy, and M. Subramani, “Closely mounted UWB
MIMO Antenna with notch characteristics for short-range
wireless video transmission application,” IETE.J.Res.,Vol.
68, no. 5, pp. 1–13, 2020.
24. S. K. Yadav, A. Kaur, and R . Khanna, “Cylindrical air spaced
high gain dielectric resonator Antenna for ultra-wideband
applications,” S¯
ahan¯
a, Vol. 45, no. 1, pp. 1–7, 2020.
25. A. K. Sohi, and A. Kaur, “UWB aperture coupled cir-
cular fractal MIMO Antenna with a complementary
rectangular spiral defected ground structure (DGS) for
4G/WLAN/radar/satellite/international space station (ISS)
communication systems,” J. Electromag. Waves Appl.,Vol.
34, no. 17, pp. 2317–2338, 2020.DOI:10.1080/09205071.
2020.1813638
26. M. Dadel, Z. Parveen, and S. Srivastava, “Compact UWB
MIMO antennas with high isolation,” IETE. J. Res.,,pp.
1–7, 2021.DOI:10.1080/03772063.2021.1942247.
27. L. Kannappan, et al. 3-D twelve-port multi-service diver-
sity Antenna for automotive communications,” Sci. Rep.,
Vol. 12, no. 1, pp. 1–22, 2022.DOI:10.1038/s41598-021-
04318-0
28. S. Thiruvenkadam, E. Parthasarathy, S. K. Palaniswamy,
S. Kumar, and L. Wang, “Design and performance anal-
ysis of a compact planar MIMO Antenna for IoT appli-
cations,” Sensors, Vol. 21, no. 23, pp. 7909, 2021.DOI:
10.3390/s21237909
AUTHORS
TSaminathanreceived his BE degree in
electronics and communication engineer-
ing from King College of Engg, Tamil
Nadu, India (aliated to Anna Univer-
sity, Chennai) in 2008 and M Tech degree
in embedded system and technology from
SRM University, Tamil Nadu, India, in
2012. Presently, he is working as an assis-
tant professor in SRMIST and pursuing PhD degree in the
Department of Electronics and Communication Engineering
atSRMIST,Chennai,India.Hisresearchinterestsinclude
monopole antenna design, multiband antenna, and MIMO
antenna design.
Email: saminatt@srmist.edu.in
P Eswaran was born in 1974, Chennai,
India. He received his bachelor degree in
electronics and telecommunication engi-
neering from the Institute of Engineers
(India) in 2000 and, the Masters in Mecha-
tronics in 2003 from Madras Institute of
Technology (India) and PhD in electron-
ics and communication engineering from
SRM University in 2014. After graduation, he joined the
as faculty in Electronics and Communication Engineering
at SRMIST (Formerly known as SRM University). His areas
ofinterestareMEMS,VLSI,DeviceModeling,EV,PVsys-
tems, embedded system, Industry 4.0. He has published over
30 reviewed international journal/conference papers, and two
Indianpatents.Hehasservedasareviewerforpeerreviewed
journals. He is also Fellow member of IE(India), Life member
of IETE, ISTE professional bodies.
Corresponding author. Email: eswaranp@srmist.edu.in