Design of 4-element Slot Loaded Patch Antenna Array for 5G Devices
1st Ganimidi Veerendra Nath Department of Electrical Engineering
National Institute of Technology Rourkela, India
2nd Bandhakavi. S Deepak Department of Electrical Engineering
National Institute of Technology Rourkela, India
3rd Konidala R. Subhashini Department of Electrical Engineering
National Institute of Technology Rourkela, India
Abstract—This paper presents a slot loaded patch antenna ar- ray for 5G devices. The 4-element antenna array has dimensions of 19.42×21.7×0.254mm3. The simulations are performed with CST Studio Suite. After simulations, the proposed antenna array has shown good results in the form of return loss, radiation pattern, and realizable gain in dBs. The proposed antenna array achieved a realized gain of 11.42 dBi with satisfactory return loss
S11<-10 dB in the targeted frequency range of 27.52-28.4 GHz.
Index Terms—Patch antenna, Slot loaded, Antenna array, 5G devices.
I. INTRODUCTION
Modern day 5G communication applications cannot com- promise either gain or bandwidth to a significant extent due to the constraints of 5G w.r.t to accuracy and speed. For this very purpose, many researchers have explored the right frequency bands of operation that offer sufficient bandwidths.
However, the designed microstrip patch antennas are to be taken care of the realizable gains, without putting the required operational bandwidths at stake. This is a challenge and most of the researchers admit the fact that, the patch antenna arrays could provide that breather to the antennas designed for 5G applications. Many such possible cases of enhancing gains to the necessary extents to meet the constraints of 5G applications can be found in the literature. Here are a few contributions in the antenna designs of 5G applications. Abdalnaser F. Kaeib [1] proposed a compact slotted microstrip antenna “Design and analysis of a slotted microstrip antenna for 5g communication networks, which covers 26.81–29.29 GHz frequency band with a peak gain of 6.37 dB.
M. B. EL Mashade [2] proposed a rectangular microstrip patch array antenna and has achieved a realized peak gain of 11.23 dB at 28 GHz. Tiago Varum [3] proposed a compact slot antenna array of 2 x 2 elements for 5G communications and has achieved a peak gain of 9.6 dB at 28 GHz. Saifur Rahman [4] described a nature inspired flower-shaped four port MIMO antenna system for Fifth Generation (5G) communication systems and has achieved a peak gain of 7.8 dB at 28 GHz frequency. Hidayat Ullah [5] proposed a novel snowflake fractal antenna for dual-beam applications in 10.15 dB at 28 GHz with a bandwidth of 2.9 GHz. Mian Muhammad Kamal [6] proposed a 4- port Multiple Input–Multiple Output
(MIMO) antenna fifth-generation (5G) 28 GHz frequency band applications and has achieved a realized gain of 5.5 dB. M U Tahir [7] proposed rhombus inscribed circular ring fractal antenna array design for mm wave 5G applications with 4 elements achieving a gain of 10.7 dB at 28 GHz. A high gain 4-element slot loaded patch antenna is designed in this paper.
Because of its high gain at 28 GHz, the designed antenna array is suitable for 5G devices.
(a) (b)
Fig. 1: Geomentry of patch antenna (a) without slots (b) with slots
II. ANTENNADESIGN
A. Slot Loaded Patch Antenna
Rogers 5880 substrate of dimensions11×5.5×0.254mm3 is used for designing the proposed slot loaded patch antenna.
“Fig. 1” displays the geomentry of proposed antenna. The con- ventional rectangular patch antenna dimensions are retrieved from the mathematical equations (1-4) by considering the free
space light velocity (c), substrate height (h) of 0.254 mm, and relative permittivity (εr) of 2.3.
1) Patch width at resonant frequency fr is calculated by using [8]
W = c 2fr
r 2
εr+ 1 (1)
2) Effective dielectric constant (εef f) is determined by using
εef f = εr+ 1
2 +εr−1 2
1 q
1 + 12Wh
(2)
3) Effective length (∆L) is determined by using
∆L= 0.412h(εef f + 0.3)(Wh + 0.264) (εef f −0.258)(Wh + 0.8) (3) 4) Actual patch length is determined by using
L=Lef f −2∆L= c 2fr
√εef f
−2∆L (4) The calculated patch dimensions are noted in Table I. The optimized dimensions of slots that are incorporated into the patch are also listed in Table I.
TABLE I: Dimensions of slot loaded patch antenna
Parameter Dimension (mm)
Ws 5.5
Ls 11
W 4.2
L 3.5
Wa 0.75
La 6
Wb 0.3
Lb 1
Wc 0.3
Lc 0.3
Wd 1.37
Ld 0.6
Le 2
B. 4-element Slot Loaded Patch Antenna Array
Rogers 5880 substrate of dimensions 19.42 × 21.7 × 0.254 mm3 is accommodated with four elements of slot loaded patch antenna along with the feed network on top and the full ground plane of dimensions19.42×21.7mm2at the bottom. In the first stage, the feed network consists of 50Ω line. A 70Ω quarter wave transformer has been utilized for matching the impedance between100Ωline and50Ωjunction point. The same procedure is reused in the next (second) stage. The arrangement of patch antenna elements with the feed network is displayed in “Fig. 2”. Each patch element in the array is separated by a distance of λ0/2. The optimized spacing between the antenna elements is 5.4 mm and the lengths of 70Ωlines are considered as 2.15 mm.
Fig. 2: Geomentry of 4-element slot loaded patch antenna array
III. RESULTS ANDDISCUSSION
The simulations have been conducted to verify the per- formance of designed antennas. From the simulation results, the single element slot loaded patch antenna has operated at desired frequency of 28GHz and also shown good results in the form of return loss at 28 GHz, radiation pattern, and realizable gain in dBs. “Fig. 3” displayed the return loss (S11) plot between 26 GHz to 30 GHz. The return loss at 28 GHz has been recorded as -20 dB and -10 dB for 27.613 GHz and 28.395 GHz frequencies, leading to an operating bandwidth of 782 MHz.
Fig. 3: Return loss (S11) plot of the proposed slot loaded patch antenna
From the 3D radiation plot shown in “Fig. 4”, the proposed antenna element achieved the 6.4 dB realized gain. Also, registered radiation and total efficiencies as -0.4982 dB and -0.5631 dB respectively.
The 2-D far-field realized gain observed at the azimuth angle Phi=0◦ has been displayed in “Fig. 5”. Similarly, the 2-D far-field realized gain observed at the azimuth angle Phi=90◦ has been displayed in “Fig. 6”. At Phi = 0◦, the main lobe
Fig. 4: 3-D Radiation pattern at 28 GHz for the proposed antenna
Fig. 5: 2-D Radiation pattern at Phi = 0◦ for the proposed antenna
Fig. 6: 2-D Radiation pattern at Phi = 90◦ for the proposed antenna
magnitude and sidelobe level are witnessed as 5.8 dB and - 17.4 dB respectively. Similarly, the direction of main lobe
and half power beam width (HPBW) are observed as 0◦ and 81◦ respectively. At Phi=90◦, the main lobe magnitude and sidelobe level are registered as 6.4 dB and -14.5 dB respectively. Similarly, the direction of main lobe and HPBW are seen as21◦ and94.8◦ respectively.
The 4-element slot loaded patch antenna array has shown some good results in the form of return loss at 28 GHz, radiation pattern, and realizable gain in dBs. The return loss plot for 4-element antenna array is shown in “Fig. 7” and is very similar to that of the return loss plot of a slot loaded patch antenna as displayed in “Fig. 3”. In the radiation pattern, the main lobe achieved a realized gain of 11.42 dB, while the radiation and total efficiencies are seen as -0.4651 dB and -0.4659 dB respectively, as presented in “Fig. 8”.
Fig. 7: Return loss plot for 4-element antenna array
Fig. 8: 3-D Radiation pattern at 28 GHz for 4-element antenna array
The 2-D radiation pattern for the antenna array at Phi=0◦ has been displayed in “Fig. 9”. Similarly, the 2-D radiation pattern for the antenna array at Phi=90◦has been displayed in
“Fig. 10”. The main lobe magnitude and side lobe level for the antenna array at Phi =0◦ have been realized as 10.3 dB and -12.6 dB respectively. The direction of main lobe and HPBW of the antenna array are spotted as 0◦ and 24.5◦ respectively.
Fig. 9: 2-D Radiation pattern at Phi =0◦for 4-element antenna array
Fig. 10: 2-D Radiation pattern at Phi = 90◦ for 4-element antenna array
Similarly, the main lobe magnitude and side lobe level for the antenna array at Phi = 90◦ are witnessed as 11.5 dB and -13.7 dB respectively. The main lobe direction and HPBW of the antenna array have been registered as 23◦ and 106.6◦ respectively. The comparison results of the single element slot loaded patch antenna and the four element antenna array are mentioned in Table II.
IV. CONCLUSION
In this paper as a first step, a single element slot loaded patch antenna is designed. This antenna element covers the 27.6-28.4 GHz frequency band with a realized peak gain of 6.4 dB. Because of better gain requirement, the proposed antenna element is being considered for creating the 4-element antenna array. The proposed antenna array offers impedance bandwidth of 27.52-28.4 GHz with resonant frequency at 28 GHz. The simulated radiation pattern shown the good value
TABLE II: Literature Comparison with the proposed antenna array
Ref Antenna Bandwidth Size in mm2 Efficiency Gain
elements (GHz) (L×W) (%) (dB)
[2] 1×4 1.2 7.07×31.677 79 11.23
[3] 2×2 1.6 36.5×32 84 9.6
[4] 2×2 2.5 25×15 95 7.8
[5] 1×4 2.9 32×12 83 10.15
[6] 2×2 3 30×30 75 5.5
[7] 1×4 6.4 28×17.75 95 10.7
proposed 1×4 0.9 19.42×21.7 90 11.42
array
of realized gain of 11.42 dB which fulfills the requirements of 5G applications.
REFERENCES
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[2] M. B. EL Mashade and E. Hegazy, “Design and analysis of 28ghz rectangular microstrip patch array antenna,” WSEAS Transactions on Communications, vol. 17, pp. 1–9, 2018.
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