Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas with Slot and Defected Ground Structure \\\\\\\\ Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal* Departement Electrical Engineering.
Universitas Indonesia.
Kampus Baru UI Depok 16424.
Indonesia Corresponding author: muhamad.
wahyu@ui.
Abstract This paper discusses the design, simulation, and realization of a leaky-wave microstrip antenna with multiple slots and defected ground structure (DGS).
The leaky-wave microstrip antenna with multiple slots and DGS was designed to operate 925-6,425 GHz for wireless local area network applications (WLAN.
, with a gain of Ou4dBi.
The antenna uses FR-4 epoxy as the substrate with a dielectric constant of 4.
6 and a thickness of 1.
6 mm.
The leaky-wave microstrip antenna has dimensions of 45.
1 mm y 24.
8 mm y 1.
6 mm, while the leaky-wave microstrip antenna with multiple slots and DGS has dimensions of 40.
6 mm y 25 mm y 1.
6 mm.
The simulation results showed that adding multiple slots and DGS to the leakywave microstrip antenna increased the bandwidth from 280 MHz .
859Ae6.
139 GH.
to 691 MHz .
854Ae6.
545 GH.
while the gain increased from 4.
47 to 5.
04 dBi.
Meanwhile, the measurement results showed that the bandwidth parameter increased from 273 MHz .
877Ae6.
150 GH.
to 684 MHz .
845Ae6.
529 GH.
and the gain parameter from 4.
53 to 5.
06 dBi at 6 GHz.
Keywords: defected ground structure.
double u-slot.
e-slot.
leaky-wave antenna.
leaky-wave microstrip antenna.
Introduction Wireless local area network (WLAN) technology is evolving rapidly.
One of the WLAN technologies is Wi-Fi.
According to a 2018 CISCO report.
Wi-Fi technology has reached 169 million hotspots and is expected to reach 628 million hotspots by 2023 .
Wi-Fi technology has considerable economic value.
It was $2 trillion in 2018 and is expected to be worth $3.
5 trillion by 2023 .
It contributes to global IP traffic, accounting for 43% of global IP traffic in 2017, which is expected to increase to 51% by 2022 .
It has been widely used to aid daily activities especially during the pandemic, such as improving connectivity, high-quality video streaming, virtual reality devices, and connectivity between modern household equipment.
Examples of Wi-Fi technology for daily activities are wireless connectivity for video meeting applications, game consoles and mobile phones, remote office cloud computing, and home automation.
It must have high reliability, high throughput, and low latency because the use of Wi-Fi continues to grow and become more popular, as it is increasingly required .
,4-.
WiFi technology based on the Ie 802.
11 standard has the following parameters: bandwidths of 40, 80, 160, and 320 MHz, an impedance of 50 E, a gain of Ou4 dBi, and operating frequencies of 2.
4 GHz, 5 GHz .
725Ae5.
GH.
, and 6 GHz .
925Ae6.
425, 5.
940Ae6.
425, 6.
425Ae6.
525, 6.
525Ae6.
875, and 6.
875Ae7.
125 GH.
The antenna is one of the technological devices used to facilitate Wi-Fi technology.
A microstrip antenna is commonly used in Wi-Fi technology.
Microstrip antennas are extensively utilized in the telecommunications industry, including for Wi-Fi technology, due to their small dimensions, inexpensiveness, and easy fabrication.
Microstrip antennas also have disadvantages, namely, gain limitations, low power, and narrow bandwidth .
The problem of narrow bandwidth can be overcome by using slots, notches, or more than one antenna element, an electromagnetic band gap (EGB), a leaky-wave antenna .
, or modifying the antennaAos shape.
One method to increase the bandwidth is using a leaky-wave antenna.
A leaky-wave antenna is part of the travelling wave antenna.
The primary mechanism of leaky-wave antennas is the antenna part.
Leaky-wave antennas are classified into four types based on their structure: simple, microstrip, uniform, and periodic leakywave antennas (P-LWA).
P-LWA leak waves travel through a uniform structure, while constant-type leaky-wave antennas leak waves through structures with nonperiodic modulation.
P-LWAs are easy to fabricate and analyze Copyright A2023 Published by IRCS - ITB
ISSN: 2337-5779
Eng.
Technol.
Sci.
Vol.
No.
3, 2023, 289-299
DOI: 10.
5614/j.
Research Paper Journal of Engineering and Technological Sciences Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal compared with uniform leaky-wave antennas.
Microstrip leaky-wave antennas can enhance bandwidth parameters, are easy to design, and can have a beam scanning frequency and narrow beam.
however, they reduce the parameter gain of conventional microstrip antennas .
Microstrip leaky-wave antennas are used for 5G communication system applications, low-cost radars, human tracking, and WLAN .
In References .
, increased gains and bandwidths were achieved.
In .
, a leaky-wave microstrip antenna with a periodic type was created with a binomial array.
In .
, the antenna used an H-slot and array technique with a size of 2 y 1.
In .
, a leaky-wave microstrip antenna of the periodic type was created using a quadrangle as a patch with the array technique and with a size of 1 y 5.
In .
, microstrip antennas were created using vertex-fed antennas with E slot.
In .
, microstrip antennas with hexagon-shaped slots modified the rectangular ground plane.
In .
, a leaky-wave microstrip antenna with a period of 24 used slots was used on the patch.
, the leaky-wave microstrip antenna used a circle slot on the edge of the patch.
In .
, the leaky-wave microstrip antenna combined a double U slot with an E slot.
Previous research using slots and a defected ground structure (DGS) succeeded in increasing the bandwidth and gain.
This study proposes using E and U slots or multiple slots on the patch, as well as a DGS at a frequency of 6 GHz, to enhance the bandwidth and gain of a conventional leaky-wave microstrip antenna.
Designing and Method In this study, the leaky-wave microstrip antenna with multiple slots and DGS had the following specifications: an operating frequency of 5.
925Ae6.
425 GHz, an impedance of 50 and a gain of Ou4 dBi.
This study used FR-4 as the substrate containing a dielectric constant of 4.
6 mm and a thickness of 1.
6 mm.
The antennaAos dimensions were calculated using Eqs.
ycO= yca uA yc.
2yceyc Oo yc The length (L) of the patch was calculated using Eqs.
yuA 1 yuAyc Oe1 yuAyceyceyce = yc Oo1 12ycO ya Leff = .
2xFr OoAeff OIL = 0.
412 x h (Aff 0.
( 0.
(Aff Oe0.
( Oe0.
Lp = Leff Oe OIL The dimensions of the ground plane and substrate were calculated using Eqs .
yaycI Ou ya 6Ea ycOycI Ou ycO 6Ea The slots were calculated using Eqs.
ya=ya= ya ycO Ou 0,3 ya= .
ya ya Oe 2.
a 2OIya Oe ycOya ) ycoycuycOoyuAyceyceyce Figure 1 illustrates the dimensions of the U-slot.
Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas DOI: 10.
5614/j.
Figure 1 Dimensions of the U-slot.
The dimensions size of the patch, the leaky-wave microstrip antenna, the substrate, and the ground were determined using Eqs.
Figure 2 shows the design of the plane of the leaky-wave microstrip antenna based on the calculation.
Table 1 shows the dimensions of each dimension parameter according to the Figure 2 Design of the conventional leaky-wave microstrip antenna as per calculation.
Table 1 Antenna dimensions as per calculation.
Parameters Dimensions .
Parameters Plk = lj Llk Dimensions .
The simulation employed CST Suite Studio.
Iteration 0 used the leaky-wave microstrip antenna as per calculation.
Iteration 1 increases the dimension of the width of the distance between the patch (Pl.
and the width of the leaky wave .
83 to 1 mm.
Finally, iteration 2 changed the dimensions of the distance between the patch (J) from 11.
6 to 10.
3 mm, the dimensions of the width of the distance between the patch (Pl.
and the width of the leaky wave .
from 1 to 1.
4 mm, the length of the leaky-wave (Ll.
76 to 10.
2 mm, the dimensions of the substrate antenna from 47 mm y 24.
5 mm to 45.
1 mm y 24.
8 mm, and the dimensions of the patch antenna from 10.
6 mm y 14.
9 mm to 12.
4 mm y 15.
5 mm.
Figure 3 shows the final design of the leaky-wave microstrip antenna, and Table 2 shows the dimensions of the leaky-wave microstrip antenna.
The simulation results are categorized into the S11, bandwidth, and gain parameters.
In iterations 0 to 2, the values of S11 at 6 GHz were Oe4.
Oe23.
39, and Oe21.
74 dB, respectively.
the bandwidth results showed operating frequencies ranging from 6.
167 to 6.
426 GHz .
MH.
, 5.
863 to 6.
087 GHz .
MH.
, and 5.
859 to 6.
139 GHz .
MH.
, respectively.
the gain result at 6 GHz is 4.
46, 4.
53, and 4.
47 dBi, respectively.
Figure 4 shows the comparison result of the S11 simulation for iterations 0 to 2.
Figure 5 shows the comparison results of the gain simulation for iterations 0 to 2.
Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal Figure 3 Table 2 Final design of conventional leaky-wave microstrip antenna.
Final design of conventional leaky-wave microstrip antenna dimensions.
Parameter Dimensions .
Parameter Plk = lj Llk Dimensions .
S11 .
B) Iteration 0 Iteration 1 Iteration 2 Frequency (GH.
Figure 4 Comparison of S11 simulation results for the conventional leaky-wave microstrip antenna.
Gain .
Iteration 0
Iteration 1
Iteration 2
5,95 5,96 5,97 5,98 5,99 6 6,01 6,02 6,03 6,04 6,05
Frequency (GH.
Figure 5 Comparison of gain simulation results for conventional microstrip leaky-wave antenna.
Eqs.
were used to increase the bandwidth and gain parameters when designing the slots and the DGS.
Figures 6.
show the design of the leaky-wave microstrip antenna design with multiple slots and DGS.
Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas DOI: 10.
5614/j.
Table 3 shows the dimensions of the leaky-wave microstrip antenna with multiple slots and DGS as per calculation.
Figure 6 Design of the modified leaky-wave microstrip antenna with .
multiple slots and .
DGS, as per Dimensions of modified leaky-wave microstrip antenna with multiple slots and DGS as per Table 3 Parameter Plk=lj Llk Dimensions .
Parameter E=E1 Lus
Pu1
Pu2
LD1
PD1=LD2
PD2
Dimensions .
Based on calculations, iteration 0 was a leaky-wave antenna with multiple slots and DGS.
In iteration 1, the widths of the E slot (E) and double U slot (E.
on the front of the antenna were changed from 0.
83 to 1 mm, and the widths of the DGS (PD.
and (LD.
were changed from 0.
83 to 1 mm.
In iteration 2, the dimensions of the patch were changed from 10.
8 mm y 14.
9 mm to 10.
7 mm x 15.
8 mm, the lower and upper outer length of the U slot on both sides (Lu.
3 to 8.
6 mm, the length of side 1 of the U (Pu.
slot from 1.
67 to 2.
7 mm, the length of side 2 of the U (Pu.
slot from 4.
4 to 5 mm, the dimensions of the distance between the patch (J) from 9 to 7.
2 mm, the dimensions of the width of the E slot (E) and double U slot (E.
on the front of the antenna from 1 to 0.
8 mm, the length of the leaky-wave (Ll.
9 to 10.
1 mm, the dimension of the width of the distance between the patch (Pl.
from 1 to 1.
3 mm, the width of the leaky wave .
from 1 to 1.
4 mm, the dimensions of the substrate antenna from 42 mm y 25 mm to 40.
6 mm y 25 mm, the dimensions of the patch antenna from 11.
6 mm y 15 mm to 10.
7 mm y 15.
8 mm, the width of DGS (PD.
from 1 to 0.
8 mm, the width of DGS (LD.
from 1 to 0.
8 mm, the length of DGS (LD.
4 to 4.
8 mm, and the length of DGS (PD.
3 mm.
Figure 7 shows the final design of the leaky-wave microstrip antenna with multiple slots and DGS, and Table 4 shows the dimensions.
Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal .
Figure 7 Final design of the modified leaky-wave microstrip antenna with .
multiple slots and .
DGS, as per Table 4 Final dimensions of modified leaky-wave microstrip antenna with multiple slots and DGS.
Parameters Plk Llk Dimensions .
Parameters E=E1 Lus
Pu1
Pu2
LD1
PD1
LD2
PD2
Dimensions .
The simulation results obtained were of the S11, bandwidth, and gain parameters.
In iterations 0 to 2, the value of S11 at 6 GHz was obtained at Oe18.
Oe5.
47, and Oe25.
49 dB, respectively.
the bandwidth showed operating frequencies of 5.
877Ae6.
1301 GHz .
MH.
, 5.
52Ae5.
702 GHz .
MH.
, and 5.
854Ae6.
529 GHz .
MH.
, the gain result was obtained at 5.
3, 5.
12, and 5.
04 dBi.
Figure 8 shows the comparison result of the S11 simulation for iterations 0 to 2.
Figure 9 shows the comparison result of the gain simulation for iterations 0 S11 .
B) Iteration 0 Iteration 1 Iteration 2 Frequency (GH.
Figure 8 and DGS.
Comparison of S11 simulation result for the modified leaky-wave microstrip antenna with multiple slots Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas DOI: 10.
5614/j.
Iteration 0
Iteration 1
Iteration 2
5,95 5,96 5,97 5,98 5,99
6,01 6,02 6,03 6,04 6,05
Frequency (GH.
Figure 9 and DGS.
Comparison of gain simulation result for the modified leaky-wave microstrip antenna with multiple slots Results and Discussion Figures 10.
show fabrication images of the conventional leaky-wave microstrip antenna, top and bottom view respectively.
Figures 11.
show fabrication images of the modified leaky-wave microstrip antennas with multiple slots and DGS, top and bottom views, respectively.
Figure 10 Fabrication images of the conventional leaky-wave microstrip antenna: .
top view, .
bottom view.
Figure 11 Fabrication images of the modified leaky-wave microstrip antenna with multiple slots and DGS: .
top view, .
bottom view.
Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal The following process was the measurement of the fabricated antennas using a vector network analyzer (VNA).
The parameters measured were S11, bandwidth, and gain.
Figures 12 and 13 show a comparison between the simulation and measurement results for S11 and gain of the conventional leaky-wave microstrip antenna.
Figures 13 and 14 show a comparison between the simulation and measurement results for S 11 and gain from the modified leaky-wave microstrip antenna with multiple slots and DGS, respectively.
In Figure 12, the dotted black line represents the simulation result of the leaky-wave microstrip antenna, with an S11 value of Oe22.
2 dB, an operating frequency ranging from 5.
845 to 6.
529 GHz, and a bandwidth of 280 MHz.
The thick line represents the measurement results of the leaky-wave microstrip antenna.
the antenna had an S11 value of Ae23.
21 dB at 6 GHz, an operating frequency ranging from 5.
877 to 6.
150 GHz, and a bandwidth of 273 MHz.
S1,1 .
B) Measurement Simulation Frequency (GH.
Figure 12 The Comparison of simulation and measuremet result of s11 conventional microstrip leaky-wave In Figure 13, the dotted black line represents the simulation results for the antenna.
The gain obtained during the simulation was 4.
47 dBi at 6 GHz.
The thick black line represents the measurement results of the antenna, showing a gain of 4.
38 dBi at 6 GHz.
Gain .
Measurement Simulation 5,95 5,96 5,97 5,98 5,99 6,01 6,02 6,03 6,04 6,05 Frequency (GHz Figure 13 Comparison between simulation and measurement result of gain for conventional leaky wave microstrip In Figure 14, the dotted black line represents the results of the antenna simulation.
it had an operating frequency ranging from 5.
854 to 6.
545 GHz, a bandwidth of 691 MHz, and an S 11 value of Oe22.
06 dB at 6 GHz.
The thick black line represents the results of the antenna measurements.
it had an operating frequency ranging from 845 to 6.
529 GHz, a bandwidth of 684 MHz, and an S11 value of Oe21.
36 dB at 6 GHz.
Bandwidth and Gain Enhancement of Microstrip Leaky-Wave Antennas DOI: 10.
5614/j.
S 1,1 .
B) Measurement Simulation Frequency (GH.
Figure 14 Comparison between the simulation and measurement results of parameter S11 for the modified leakywave microstrip antenna with multiple slots and DGS.
In Figure 15, the dotted black line represents the result of the antenna simulation.
The antenna gain obtained during the simulation was 5.
04 dBi at 6 GHz.
The thick black line represents the result of the antenna The antenna gain obtained during measurement was 5.
06 dBi at 6 Ghz.
Gain Measurement 5,95 5,96 5,97 5,98 5,99 Simulation 6,01 6,02 6,03 6,04 6,05 Frequency (GH.
Figure 15 Comparison of the simulation and measurement results of gain for the modified leaky-wave microstrip antenna with multiple slots and DGS.
From the simulation results, the bandwidth and gain parameters of the leaky-wave microstrip antenna with multiple slots and DGS increased from 280 to 691 MHz or 411 MHz and from 4.
47 to 5.
04 dBi or 0.
57 dBi at 6 GHz, respectively, while the measurement results showed an increase in the bandwidth and gain from 273 to 684 MHz or 411 MHz and from 4.
38 to 5.
06 dBi or 0.
68 dBi at 6 GHz, respectively.
Table 5 shows a comparison between the simulation and measurement results of the bandwidth and gain enhancement for the conventional and modified leaky-wave microstrip antennas with multiple slots and DGS.
Table 6 shows a comparison of the proposed antenna and previous antennas.
In this research, the antenna was smaller than those used in .
and had a wider bandwidth than those in .
In .
, the antenna had a working frequency of 64.
2 GHz and 91.
5 GH, which makes it unsuitable for Wi-Fi application.
Table 5 Comparison of simulation and measurement of bandwidth and gain enhancement.
Parameter Bandwidth Simulation Gain Bandwidth Measurement Gain Enhancement 280 MHz .
859Ae6.
139 GH.
to 691 MHz .
854Ae6.
545 GH.
47 dBi to 5.
04 dBi 273 MHz .
877Ae6.
150 GH.
to 684 MHz .
845Ae6.
529 GH.
38 dBi to 5.
06 dBi Fitri Yuli Zulkifli & Muhamad Wahyu Iqbal Comparison between proposed antenna and previous antennas.
Table 6 Ref Frequency (GH.
Bandwidth 28 Ae7.
8 GHz 2 and 91.
3Ae6.
18Ae5.
17, 4.
95Ae5.
35, and 76 Ae6.
16Ae7.
4Ae6 28Ae6.
843Ae6.
33 GHz and 15.
GHz 2 GHz 430, 400, and 250 MHz 3691 GHz 2 GHz 22 GHz 615 MHz 845Ae6.
685 MHz This Works Gain .
5 at 6 GHz and peiak gain is 31 at 5 GHz Dimensions .
33 and 12.
14 y 14 y 0.
10 at 5 GHz 250 y 100 y 1.
25, 3.
01, and 4.
50 y 50 y 1.
10 at 4.
3 GHz 31 at 5 GHz 34 y 20 y 0.
250 y 100 y 1.
180 y 40 y 1.
9 y 23.
90 y 1.
6 y 25 y 1.
180 y 40 y 1.
Conclusion This study investigated the design, simulation, fabrication, and measurement of a conventional leaky-wave microstrip antenna and a modified leaky-wave microstrip antenna with multiple slots and DGS.
The latter was successfully designed for WLAN applications at 6 GHz.
The dimensions for fabrication of the conventional leakywave microstrip antenna were 45.
1 mm y 24.
8 mm y 1.
6 mm, and 40.
6 mm y 25 mm y 1.
6 mm for the leakywave microstrip antenna with multiple slots and DGS.
The simulation and measurement results showed that adding multiple slots and a DGS increased the bandwidth and gain parameters of the leaky-wave microstrip The simulation results showed that the bandwidth increased from 280 MHz .
859Ae6.
139 GH.
to 691 MHz .
854Ae6.
545 GH.
and the gain increased from 4.
47 to 5.
04 dBi, while the measurement results showed that the bandwidth increased from 273 MHz .
877Ae6.
150 GH.
to 684 MHz .
845Ae6.
529 GH.
and the gain increased from 4.
38 to 5.
06 dBi.
Acknowledgement This work was supported by Postgraduate Research - Master's Thesis Research (Penelitian PascasarjanaPenelitian Tesis Magister/PPS-PTM) from the Ministry of Education.
Cultural Research, and Technology (Kemendikbu.
Republic of Indonesia, under contract number NKB-1033/UN.
RST/HKP.
00/2022.
Nomenclature free-space velocity of light .
y 108 M/S) resonant frequency (H.
substrate thickness Ar
dielectric constant of the dielectric substrate (F/M) Aeff
the effective dielectric constant of the substrate (F/M) element edge field effect
References