Manumula Srinubabu*
| Nuthakki Venkata Rajasekhar
© 2024 The authors. This article is published by IIETA and is licensed under the CC BY 4.0 license (http://creativecommons.org/licenses/by/4.0/).
OPEN ACCESS
This paper describes the compact design of a 4-port MIMO (multi-input, multi-output) antenna with enhanced diversity parameters for the n78/77/48 5G band. The proposed 4-port MIMO antenna design consists of a symmetrical two-pair monopole antenna placed closely (less than space diversity of λmax/2). The MIMO antenna design incorporates Rogers RO3003 substrates with a εr of 3.2. The antenna size is compact, with dimensions of 78×64.5×1.6 mm3 with enhanced isolation and diversity parameters. The T-shaped stub is etched from the ground and incorporated with grounding branching in the middle of the ground plane, which enhances the bandwidth, gain, and isolation. Moreover, placing a horizontal or vertical decoupling element between the two sets of antennas obstructs the reverse current path and reduces the S21. The proposed antenna has an envelope correlation coefficient (ECC) of 0.00789, a diversity gain (D.G.) of 9.96 dB, a total effective reflection coefficient (TARC) of < -10 dB, a mean effective gain (MEG) of 0.01 dB, a channel capacity loss (CCL) of 0.24 bps/Hz, a peak gain of 4.4 dBi, and a radiation efficiency of 98.85% across the specified range, respectively. In addition, S21 is -22 dB across the bands. Further, the suggested antenna also has the advantages of compact size and better diversity parameters, which ensure its compatibility with modern n78/77/48 band 5G systems, Wi-Max bands, and V2V applications.
MIMO antenna, modified ground, decoupling, Isolation, efficiency, diversity parameters, 5G-NR n78/n77/n48 bands
The progression of fifth-generation (5G) wireless technology is swift, providing enhanced data rates, minimal latency, enhanced bandwidth, and improved connectivity [1-4]. To support these advanced features, the 5G system employs a new radio spectrum, functioning within frequency range 1 (FR-1, sub-6 GHz) and frequency range 2 (FR-2, the mm-wave band). N78 is one of the many sub-bands in the FR-1 5G NR spectrum. It employs an orthogonal orientation in its construction and operates as a WiMax band from 3.3 to 3.8 GHz [5-8]. The N78 band is likely to have a significant impact on the rollout of 5G networks. Multiple-input, multiple-output (MIMO) antennas become very important in 5G communication design in cities, especially where the short range and poor coverage of high-frequency bands make real-time use cases difficult [3, 9-12]. MIMO antennas play a pivotal role in enhancing the data rates and signal quality for 5G networks. By employing multiple antennas on both the transmitter and receiver sides, MIMO technology enhances the spectrum efficiency of wireless systems. But mutual coupling between antenna elements are a big problem in MIMO systems [1, 2, 13]. The antennas need to be well separated from each other to prevent interference and cross-talk between channels. In the real world of microstrip antennas, there persists dissatisfaction within the electromagnetic community regarding size reduction and the need for bandwidth enhancement. Hence, the design of a compact MIMO antenna becomes imperative for achieving optimal system performance. This paper introduces a compact, four-port MIMO antenna tailored for improved diversity, performance, and effective isolation in the N78 5G bands. The antenna is specifically crafted to operate within the frequency range of 3.3 to 3.8 GHz [2, 4, 14-17]. which is a critical frequency band for 5G communication. The diversity approach [18-20] is one of several strategies used to increase isolation. Along with these, there are metamaterials, decoupling elements (DE), electromagnetic band gaps (EBG), defective ground structures (DGS) [21], and ways to separate MPS radiators. Defected or modified ground structure (MGS) [21-23], parasitic parts [2, 24], neutralization boundary [2, 25], electromagnetic band gap design [2, 26, 27] and decoupling structures (DS) [2, 7, 8, 27-32] are also imprinted in MIMO antennas for enhancing bandwidth and isolation.
The simulation results indicate the effectiveness of the proposed antenna design, showcasing favorable impedance matching, improved isolation, better diversity performance, and consistent radiation patterns for the n78/77/48 5G band. The following sections provide a detailed exploration of the antenna design, methodology, simulated and experimental outcomes, and concluding remarks on the proposed antenna.
This section examines the complete evolution of the finalized antenna's design and performance in various scenarios. The following segments offer a thorough and systematic explanation of the design approach employed for the antenna. A single-monopole antenna is designed with DGS techniques for enhancing bandwidth and good impedance matching. 2-port MIMO antennas implemented different techniques (mirroring techniques, decoupling elements, and grounding branches) for isolation enhancement to reduce mutual coupling between the antennas for better antenna design. The proposed 4-port MIMO antenna incorporated another decoupling element between the 2×1 configuration for enhanced isolation for the required operating band (n77, 78, and 48 bands).
2.1 Single monopole antenna design evolution
This section describes the evolution of antennas over time and their performance in different situations. The following segments offer a thorough and systematic explanation of the design approach employed for the antenna. Figure 1 depicts the single monopole antenna step-by-step evolution with microstrip feeding, which is formed by a triangular cut etched from a rectangular patch antenna having dimensions of 34×35×1.6mm3 and a loss tangent factor of 0.0013, which is referred to as Ant._1.
Figure 1. Single antenna evolution and geometry of optimized single monopole antenna [l1=27, l2=6, l3=22, l4=8.6, l5=16, fl=5, s1=35, s2=34, g1=6, g2=8.5, g3=20, g4=2, g5=2.5] (All values are in mm.)
The antenna is affixed to a substrate of Rogers R03003 with a dielectric constant value (εr) of 3.2. Here is a rectangular slot etched from the ground planes, which is shown as Ant._2, which notably improves the antenna's bandwidth, gain, and performance, and a refined single monopole antenna featuring a T-slot etched into the ground plane, referred to as the modified ground of the optimized antenna (Ant._3), as depicted in Figure 1.
2.2 2-Port MIMO antenna configuration
Figure 2 depicts the progression of the incremental evolution of the 2-element MIMO antenna. The overall dimension of this antenna is 34×64.5×1.6 mm3. The symmetrical antennas are printed vertically and share a common ground, as shown in Figure 2(a). The conventional space between the antennas indicates the space diversity of the side-by-side antennas (G=43 mm) at 3.52 GHz, which is calculated by using Eq. (1) [7, 8, 31]. The center-to-center distance is adjusted from 31.5 mm to 33.5 mm, showcasing space diversity. To boost the antenna performance, a parametric study optimizes 'G' to 32.5 mm for a more compact design with enhanced diversity parameters.
$\begin{gathered}G=\frac{\lambda_{\max }}{2} \\ \lambda_{\max }=\frac{c}{f}=300 / 3.52=85.2271 \mathrm{~mm} \\ \frac{\lambda_{\max }}{2}=\frac{85.2271}{2}=42.61 \mathrm{~mm}\end{gathered}$ (1)
Eq. (2) [7, 8, 30] is used to calculate the isolation between two antennas. The isolation determines the degree of interference between the antennas and can affect the overall system's performance levels. For instance, the coupling coefficient (Sij) is a measure of the coupling between two antennas (i & j).
$\begin{gathered} { Isolation }=20 \log _{10}\left(\frac{1}{\sqrt{\left(1-\left|S_{i j}\right|^2\right)}}\right) \\ { Isolation }=-20 \log _{10}\left(S_{i j}\right) \\ { Isolation }=-20 \log _{10}(0.0794)=22 \mathrm{~dB}\end{gathered}$ (2)
Figure 2. Geometry of the two-port MIMO antenna (a),(b),(c) evolutions of Ant.-a, Ant.-b, and Ant.-c [s3=64.5, d1=17, d2=1, d3=23, d4=0.5, a=4.75, b=4.5, c=3] (All values are in mm.)
In addition, the T-shaped slot etching from the ground plane modifies the current distribution in the antennas and mitigates coupling. Figure 2(b) depicts the second element's mirrored image of the first element, which diminishes the antenna's. The dimensions remain the same, and a centre slot is incorporated in the middle of the common ground. Furthermore, by including a vertical grounding branch element connected to the ground, it can generate a new coupling current and further mitigate the coupling of the Ant._c. Strategically, the optimized decoupling element has a length (d1) of 17mm (ranging from 15 to 21 mm) and a width (d2) of 1mm (ranging from 0.5 to 2.5 mm). In the rear view, the Ant._c grounding branch length (d3) is optimized at 23mm (ranging from 21 to 25 mm) with a width (d4) of 0.5mm. This design alters the current pathway within the ground plane and the patch, which mitigates the interference between the antennas and enhances the isolation compared to the previous design.
2.3 The proposed 4-port MIMO (2×2 configuration) antenna design
The proposed design is illustrated in Figure 3. In this method, two 2-element MIMO antennas are placed orthogonally and extended. Another decoupling stub is then placed strategically between the two 2-element MIMO antennas, as shown in Figure 3(a). The optimized width (d5) is 1mm (ranging from 0.25 to 1.25mm) and length 64mm, which reduces the S21 and enhances the planned antenna performance for real-time scenarios. The final optimized dimension of the suggested 4-port MIMO antenna for this design is 78×64.5×1.6 mm3 and adds the substrate between two antenna pairs with another decoupling element. As a result, the suggested modified ground and stub can efficiently reduce S21 between the antenna ports to achieve the desired diversity performance in the 5G MIMO antenna design.
Figure 4 depicts the fabricated prototypes of the proposed antennas with 50Ω SMA connectors.
Figure 3. The suggested 4-port (2×2) MIMO antenna showcases (a) the front view and (b) the rear view. The provided parameters consist of [d5=1, S3=64.5, S4=78], with all measurements in mm
Figure 4. The fabricated snapshots of a 4-port MIMO antenna with SMA connectors are presented in (a) the top view and (b) the rear view
Figure 5 depicts the testing setup of the designed MIMO antenna using an Anritsu VNA MS2037C/2 vector network analyzer utilized to validate the operational capabilities. In this setup, Port 1 is excited while the other ports are set with 50-ohm matching. Figure 5(a) shows the measuring setup of Sxx in dB and Figure 5(b) shows the measurement of Sxy in dB.
Figure 5. Anritsu VNA MS2037C/2 setup for testing a proposed 4-port MIMO antenna (a) measuring Sxx in dB and (b) measuring Sxy in dB
In Figure 6(a), the results of S11 illustrate the step-by-step evolution of single monopole antennas (Ant.-1,2, and 3). Ant.-3 changes its frequency response as it evolves and gets better, which leads to better power transfer at the receiver end and greater impedance matching with S11<-10 dB. This optimization achieves a bandwidth of 2.8–4.2 GHz, reaching -28.5 dB at 3.6 GHz. Figure 6(b), on the other hand, shows a separate parametric analysis of a single antenna that has been optimized and has a ground plane length of g2=g4=8.5mm (between 8 and 9mm). It covers the same required band with superior impedance matching, with S11 measuring -41.5 dB at 3.6 GHz.
The simulation results of the 2-identical element arranged in a linear manner (MIMO configuration) with varying gap lengths (G) are depicted in Figure 7(a). The observed S-parameters show G ranging from 31.5 to 35mm, with the maximum gap at 35 mm, indicating increased signal reflection. A notable improvement is achieved at 32.5 mm; it achieves 1.39 GHz in the frequency spectrum of 2.81–4.2 GHz. Figure 7(b) visually presents the S21values corresponding to various isolation techniques explored in this study, encompassing symmetry, mirroring techniques (-12.3 dB to -15.7 dB), and optimized decoupling employing grounding branch elements of modified ground (-15.7 dB to -22 dB).
Figure 6. Simulated monopole antenna results of S11(dB). (a) Evolution of antenna corresponding results. (b) various g2 values with and without triangle cut
Figure 7. Simulation outcomes of a 2×1 MIMO antenna. (a) Simulated results Sxx of the gap (G) between the antennas. (b) Evolution S21 results of the 2-port MIMO configuration
Figure 8. Simulated parameterized S21 outcomes for a 2×1 MIMO antenna. (a) Different lengths (d1). (b) Different widths (d2). (c) Various lengths (d3). (d) Different positions of the decoupling element (XPos. and YPos.)
Figure 9. The simulation results for a 2×1 MIMO antenna. (a) Results depicting varied positions of the grounding branch. (b) S-parameter outcomes for the optimized 2×1 MIMO antenna
Figure 10. The Sxy (dB) characteristics of the suggested four-port MIMO antenna based on a simulated d5 parametric analysis
Figure 8 shows a different set of parametric analyses that focus on the isolation techniques that were used, with a focus on the decoupling stubs (DS) and grounding branch with modified ground. The length of the DS, denoted as d1, varies from 15mm to 21mm, leading to S21 values ranging from -17 dB to -22.5 dB. Following optimization, d1 is set at 17mm, achieving S21 of -17 dB, as depicted in Figure 8(a). The width of the DS, labeled by d2 , ranges from 0.5 to 2.5mm, resulting in S21 values from -16.5 dB to -22 dB. After optimization, d2 is determined to be 1mm, resulting in an S21 of -22 dB, as depicted in Figure 8(b).
In Figure 8(c), the width (d4) of the grounding branch is fixed at 0.5mm. Meanwhile, the length, denoted as d3, varies from 21mm to 25mm, yielding S21 values ranging from -16.5 dB to -22.5 dB. Following optimization, d3 is set at 23mm, achieving an S21 of -22.5 dB. The effectiveness of isolation depends not only on the dimensions but also on the positioning of the DS and the modified ground. Figure 8(d) displays the varying positions of the DS, ranging from 8.5mm to 17.75mm, resulting in S21 values from -11 to -22 dB. The fixed coordinates for XPos. and YPos. are set at -8.5mm and -16.75mm, respectively, measured from the center of the ground plane. Figure 9(a) illustrates the positioning of the grounding branch in the middle of the modified ground, adjusting XPos. and YPos. in a range from 16.25mm to 18.5mm. After optimization, the ideal XPos. and YPos. are determined to be 16.25mm each, achieving superior performance with low coupling and a remarkable S21 of below -22 dB.
The optimization of the feed ground cut (c) at 3mm is based on the simulation results from the grounding branch, as depicted in Figure 9(b). Based on these findings, the best MIMO antenna (2×1) with a 2 GHz bandwidth can get an impedance value of -54.5 dB at 3.52 GHz and an S21 value below -23.25 dB.
The suggested four-port MIMO configuration incorporates an additional decoupling element (DE) positioned in the middle of the straight lines connecting the two-element MIMO pairs. The optimized DE length is 64mm, and the width d5 varies from 0.5 to 1.25mm. The simulated Sxy results are depicted in Figure 10, showcasing different Sxy levels below -15 dB from one antenna to the rest of the antennas. After optimization, d5 is set at 1mm, achieving improved S21 of -22 dB, S31 of -26 dB, and S41 of -31 dB.
Figure 11. Distribution of simulated electric field at the front-line antenna of a 2×1 MIM0 antenna at 3.52 GHz. (a) Port 1 excited with and without coupling element. (b) Port 2 excited with and without coupling element
The progressive use of all isolation techniques and strategic placement (XPos., YPos.) of the decoupling element dimensions (d1, d2, d3, d4, and d5) in the design reduces the electric field that gets coupled from one element to another, resulting in an enhancement of the isolation (S21). Figure 11 depicts the distribution of the electric field within the 2-element configuration at 3.52 GHz. It showcases the impact of a decoupling element on the enhancement of the isolation techniques. As depicted in these results, more electric fields get coupled to the neighbouring element when no decoupling elements are present. A reduction in the electric field that gets correlated from one element to another is achieved by strategically placing the decoupling elements in the design, which mitigates the coupling (S21) of one antenna to another.
Furthermore, the isolation varies when decoupling elements are introduced between the antennas of the four-port MIMO configuration. In this examination, one port (the antenna source) is excited while the remaining ports are terminated with 50 ohms. In Figure 12, when the first port is activated without the decoupling elements, the antenna elements 2-4 exhibit higher coupling. Upon the incorporation of the decoupling elements, the coupling is diminished as these elements block the coupling current between the antennas. Similar scenarios unfold when the remaining ports are activated.
A similar improvement in the coupled electric field is achieved over the complete N77, N78, and N48 frequency bands with the use of the decoupling elements. The experimental results are examined and contrasted with the actual simulation results of the suggested four-port MIMO (2×2) configuration. The next sections provide a detailed study of the comparison between the experimental and generated results. For brevity, this paper the discusses results based on the 2-way antenna, and the remaining antennas are symmetrically matched. The simulation and measurement parameter values for reflection coefficient, transmission coefficient, TARC, ECC, DG, CCL, gain and radiation pattern, multiplexing efficiency, and MEG for different configurations can be observed in Figures 13-20. The comprehensive outcomes of the final designed four-port MIMO configuration antenna are elaborated as follows.
Figure 12. Simulated surface current density distribution at the front line antenna of a 4-element with and without decoupling element (DE)3 MIM0 antenna at 3.52GHz
3.1 S-parameters (Sii and Sij)
A comparison plot of the simulation and measurement Sii-parameters results for the four-port MIMO design is shown in Figure 13(a).
This plot facilitates a visual assessment of the agreement or variance between the simulated and experimentally measured values of the S-parameters of the system. Sii is at -35 dB at 3.52 GHZ; it indicates a low level of reflection, which is desirable for efficient signal transmissions and suitable impedance matching across the bandwidth. The Sii curve of the suggested 4-port MIMO antenna achieved a bandwidth (Sii <-10 dB) of 1.50 GHz (ranging from 2.7 GHz–4.2 GHz). The observed variation could be the result of fabrication tolerance. It is suitable for the FR-1 sub-bands denoted as n77 (TDD 3.300–4.200 GHz), n78 (TDD 3.300–3.800 GHz), and n48 (TDD 3.550–3.700 GHz) bands of 5G-NR applications. In Figure 13(b), the transmission coefficient measures the amount of energy transmitted by the antenna to the receiver. Figure 13(b) compares the actual results with the expected ones. At the lower band, S21 is -21 dB; at the upper band, it is -25 dB; and the overall band attains -22 dB. The recommended 4-port MIMO antenna achieves higher isolation.
Figure 13. Comparison of the 4-port MIMO antenna simulation and experiment results. (a) Sxx parameters. (B) Sxy parameters
3.2 Diversity parameters
3.2.1 Total active reflection coefficient (TARC)
The measure of the TARC between two ports is calculated by Eq. (3) [22, 30-32]. For brevity, this paper considers a 2-way TARC and the other two ports to be matched in a 4-port MIMO antenna due to its identical structure.
${TARC}(\Gamma)=\sqrt{\frac{\left|S_{i i}+S_{i j}\right|^2+\left|S_{j i}+S_{j j}\right|^2}{2}}$ (3)
The actual and determined TARC results, shown in Figure 14, are both <-10 dB of the targeted band. The TARC parameter is evaluated using the relation, which indicates a good reflection and signal low loss level, ideal for efficient signal transfers.
Figure 14. Simulated and measured TARC (dB) results vs. frequency (GHz)
3.2.2 Envelope correlation coefficient (ECC)
Eq. (4) [22, 31] calculates the ECC according to scattering parameter values across various ports, and Eq. (5) [22, 31, 32]. computes the radiation pattern. The ECC24 value is 0.001, indicating a relatively lower value. Similarly, the ECC12 value is measured to be 0.015. When considering the overall average ECC for all ports, it amounts to 0.0078. On the other hand, a contrast of the observed and modeled results is shown in Figure 15(a), explicitly highlighting the ECC values. In this case, the ECC13 value is 0.001, indicating a low value. The ECC34 value is 0.35. This is significantly elevated and quantifies the degree of correlation between the signal envelopes acquired by the system's several antenna ports.
$E C C=\frac{\left|S_{i i}^* S_{i j}+S_{j i}^* S_{j i}\right|^2}{\left(1-\left|S_{i i}\right|^2-\left|S_{j i}\right|^2\right)\left(1-\left|S_{j j}\right|^2-\left|S_{i j}\right|^2\right)}$ (4)
$E C C=\frac{\mid \iint_{4 \pi}^{\cdot}\left[\left.E_i(\theta, \emptyset) * E_j(\theta, \emptyset) d \Omega\right|^2\right.}{\left.\left|\iint_{4 \pi}^{\cdot}\right| E_i(\theta, \emptyset)\right|^2|d \Omega *| \iint_{4 \pi}^{\cdot}\left|E_j(\theta, \emptyset)\right|^2 \mid d \Omega}$ (5)
A lower ECC value indicates better diversity performance. In the mentioned work, an ECC value of 0.0078 is achieved, significantly below the acceptable threshold of 0.5. The ECC values obtained from the S-parameters and the far-field radiation patterns are displayed in Figure 15 (b). ECC pertains to comparing the radiation patterns and scattering properties between each pair of the suggested antenna ports.
Figure 15. Comparative ECC results. (a) simulation vs. measurement results based on S-parameters. (b) simulation results based on far-field and S-parameters
3.2.3 Diversity gain (DG)
Eq. (6) [22, 31, 32] determines the DG based on ECC characteristics between different ports. Figure 16 shows the diversity gain of the final-designed antenna. The obtained values indicate a significant improvement in signal quality and performance.
$D G=10 * \sqrt{\left(1-E C C^2\right)}$ (6)
Figure 16. Simulated and measured results of the DG (dB)
For this scenario, the minimum D.G. value is 9.94 dB, while the higher value is 9.98 dB. Furthermore, the overall DG is 9.96 dB. These values indicate that the system is capable of significantly enhancing signal quality through the use of multiple antennas.
3.2.4 Channel capacity loss (CCL)
Figure 17 shows the simulated CCl results for the suggested four-port MIMO configuration based on the s-parameters set to different ports. With ports 3-4, it attains a data rate of 0.24 bits/s/Hz, while the remaining ports reach a rate of 0.05 bps/Hz. Eq. (7) [22, 33] determines the CCL based on radiation and S-parameter characteristics between different ports. CCL indicates a relatively low level of correlation, which means that the system can achieve good diversity and minimize interference from other signals.
$C C L=-\log _2 \operatorname{det}(A)$ (7)
where, $A=\left[\begin{array}{ll}a_{11} & a_{12} \\ a_{21} & a_{22}\end{array}\right], a_{i i}=1-\left(\left|S_{i i}\right|^2+\left|S_{i j}\right|^2\right), a_{i j}=\left(S_{i j}^* S_{i j}+S_{j i} S_{j j}^*\right)$, for I, j=1 or 2 .
Figure 17. Results of measurements and simulations for the CCL (bps/Hz)
3.2.5 Mean effective gain (MEG)
MEG is calculated using Eq. (8) [34]. The channel is assumed to be Rayleigh with identical polarization densities for improved channel characteristics and diversity performance. The criteria of K= MEGi.-MEGj. less than 3 dB are considered, and Figure 18 illustrates that the MEG is less than 0.01 dB, indicating a favorable outcome.
$M E G_{i .}=0.50 \eta_{i .,} r a d=0.50\left[1-\sum_{j.=1}^N\left|S_{i, j}\right|^2\right]$ (8)
Figure 18. Comparative results of measurements and simulations for the MEG (dB)
3.2.6 Gain and radiation efficiency, radiation pattern
Figure 19 shows the suggested four-port MIMO antenna's measurement and simulation results for the gain, as well as a plot of the radiation efficiency against frequency. The results indicate a consistent variation, showcasing stable gain within the range of approximately 3.5 to 4.7 dBi and radiation efficiency spanning from 97% to 98.85%. Notably, these observed values are slightly lower than those predicted by the simulation. It is better for MIMO antennas to work in certain 5G frequency bands because they can send and receive more information without any problems. The suggested antenna design achieved a high radiating efficiency of over 98.85%.
Figure 19. Simulated versus measured results. (a) peak gain (dBi) versus frequency. (b) simulated radiation efficiency vs. frequency results
The radiation patterns of a two-dimensional (2D) MIMO antenna are shown in Figure 20. It shows both cross-polarization and co-polarization effects. The radiation characteristics are evaluated at 3.52 GHz and analyzed in both the YZ-plane (φ=0°) and the XY-plane (φ=90°) as the E and H-planes. Noteworthy enhancements were detected at these resonant frequencies, indicating reduced cross-polarizatio thereby positively influencing the overall antenna performance. While monitoring the pattern of power radiated from one port, the rest of the ports are matched. Table 1 presents the state-of-the-art advancements in the proposed antenna. It has conducted a comparative analysis to evaluate the proposed antenna against existing research. The proposed MIMO antenna achieves high isolation (S21), 98% efficiency, and demonstrates good diversity performance.
Figure 20. Evaluating and contrasting the radiation patterns for antenna 1 across the YOZ and XOZ planes
Table 1. State-of-the-art analysis to compare the suggested antenna with the existing research
|
Ref. |
Size (mm2) |
S21 (dB) |
ECC |
D.G. (dB) |
TARC (dB) |
M.E.G (dB) |
CCL (bps/Hz) |
Efficiency (%) |
Gain (dBi) |
No. of Ports |
Year |
|
[31] |
133 × 133 |
16.5 |
0.001 |
- |
- |
- |
- |
84 |
5.2-6.8 |
4 |
2020 |
|
[35] |
60 × 60 |
19 |
0.12 |
- |
- |
- |
0.349 |
- |
- |
4 |
2020 |
|
[1] |
180 × 180 |
14 |
0.01 |
- |
- |
-7.96 |
- |
70 |
0.05, 4.4, 6.9, 5 |
4 |
2021 |
|
[36] |
70 × 145 |
20 |
0.5 |
- |
- |
- |
- |
70 |
4-5.5 |
4 |
2021 |
|
[37] |
100 × 100 |
15 |
0.03 |
- |
- |
-5 |
- |
80 |
6.1-7.5 |
4 |
2021 |
|
[38] |
90 × 90 |
25 |
0.5 |
9.8 |
- |
- |
21 |
74 |
4 |
4 |
2022 |
|
[39] |
55 × 55 |
15 |
0.017 |
- |
- |
- |
- |
68 |
4 |
4 |
2022 |
|
[40] |
120 × 60 |
15 |
0.12 |
9.9 |
- |
- |
- |
76-91 |
- |
4 |
2022 |
|
[41] |
65 × 60 |
15 |
0.13 |
9 |
-12.5 |
1.0057 |
- |
- |
- |
4 |
2022 |
|
[42] |
72 × 72 |
15 |
0.005 |
10 |
-10 |
-3 |
0.05 |
72 |
2.5 |
4 & 8 |
2023 |
|
P.A. |
64.5 × 78 |
22 |
0.00789 |
9.96 |
-15 |
0.05 |
0.08 |
98 |
4.4 |
4 |
present |
The two-element antenna and four-element (2×2 configuration) MIMO antennas in this work are designed to make 5G-NR (n77/n78/n48 bands) communication systems more efficient, improve diversity, and improve isolation. The suggested 4-port MIMO antenna has an S11 of -35 dB (2.7–4.2 GHz), an isolation s21 of -22 dB, a TARC of -10 dB, an ECC level of 0.0078, and a DG of 9.96 dB. These results show that the system can achieve good diversity performance and better performance levels. Its low CCL level of 0.05 bps/Hz shows that it can handle other signals without much trouble and has a good radiation pattern in the co- and cross-polarization, giving it a gain of about 4.4 dBi. One potential area of future development is using advanced materials and fabrication techniques to further optimize these antenna configurations' performance. For example, using metamaterials or other novel materials can help improve the antenna diversity parameters. Another area of future development is the integration of these antenna configurations with other wireless technologies such as 5G, IoT, and satellite communication systems. Furthermore, there is a prospect for additional optimization of the antenna configurations using machine learning (ML) and artificial intelligence (AI) methodologies.
I wish to extend my sincere appreciation to Dr. N. V. Rajasekhar, my mentor, for his invaluable guidance, expertise, and unwavering support during the entire duration of this research. The direction and quality of this essay were greatly influenced by Dr. Rajasekhar's vast expertise, smart inputs, and persistent support. Additionally, I express my gratitude to VIT-AP University for the comprehensive provision of resources and facilities throughout the course of my work.
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