Eight Element Wideband Antenna with Improved Isolation for 5G Mid Band Applications

Abstract

Modern wireless communication systems have undergone a radical change with the introduction of multiple-input multiple-output (MIMO) antennas, which provide increased channel capacity, fast data rates, and secure connections. To achieve real-time requirements, such antenna technology needs to have good gains, wider bandwidths, satisfactory radiation characteristics, and high isolation. This article presents an eight-element CPW-fed antenna for the 5G mid-band. The proposed antenna consists of eight symmetrical, modified circular monopole antennas with a connected CPW-fed ground plane that offers 24 dB isolation over the operating range. The antenna is further investigated in terms of the scattering parameters, and radiation characteristics under both the x and y-axis bending scenarios. The antenna holds a volume of 83 × 129 × 0.1 mm³ and covers a measured impedance bandwidth of 4.5–5.5 GHz (20%) with an average gain of 4 dBi throughout the operating band. MIMO diversity performance of the antenna is performed, and the antenna exhibits good performance suitable for MIMO applications. Furthermore, the channel capacity (CC) is estimated, and the antenna gives a value of 41.8–42.6 bps/Hz within the operating bandwidth, which is very close to an ideal 8 × 8 MIMO system. The antenna shows an excellent match between the simulated and measured findings.

1. Introduction

The Sub-6 GHz 5G technology has become a critical component in 5G deployment due to several merits other than the higher frequency (mm-Wave), like wider coverage in rural areas, lower power consumption, higher penetration, higher data rate, and mobility [1,2]. The growing demand for such a high data rate communication system seeks a technology where multiple antennas are utilized at the transmitter as well as receiver to enhance the channel capacity of the communication link without increasing the transmission power and the bandwidth [3,4,5]. MIMO technology continues to serve as the foundation for 5G wireless communication networks. In addition to the multipath characteristics of the communication channels, the performance of such a system relies on the meticulous design of the MIMO systems. Nowadays, low-profile wideband antennas are gaining popularity due to their ease of fabrication and cost-effectiveness as well as compact sizes. In this context, the design of flexible antennas needs greater attention, especially in compact devices with space constraints where the antennas are placed closer to each other leading to strong mutual coupling between them. The extensive coupling between the inter-elements leads to low efficiency. In MIMO systems, successful communication requires isolation among elements of more than 12 dB [5]. There have been several methodologies implemented recently to reduce the coupling and thereby increase the isolation like the use of parasitic elements [6], defective ground structures [7], stubs [8], self-isolating decoupling structures [9,10], lozenge structures [11], artificial intelligence approaches [12] and so on.

In recent years, numerous flexible antennas using two ports [8,13,14] and four ports [11,15,16] have been modeled for the 5G mid-band. In [8], a compact and more isolated dual-port antenna is presented. The antenna offers good impedance matching and satisfactory omnidirectional patterns with co-cross coupling, but the bandwidth is low. A wideband wearable antenna with a neutralization line (NL) between the radiators is presented in [14]. The NL provides remarkable isolation of 32 dB for the working bands. However, the antenna is vulnerable to antenna performance degradation due to the use of textile substrates prone to absorbing moisture. A transparent and flexible two-element antenna that utilizes the wired metallic mesh is proposed in [13] for 5G internet-of-things (IoT) applications. The antenna is compact, but the gain and efficiency of the antenna are low. In [11], a four-port multiband antenna with a modified decagon substrate is examined for wireless applications. The antenna provides satisfactory gain and multiband operation. Another quad-element antenna is proposed in [16]. In the primary planes (E and H), the antenna displays good omnidirectional and bidirectional patterns, respectively. The antenna bandwidth and efficiency are good and are appropriate for the intended applications. However, the number of users that [11,16] can support is still quite small.

An increase in the number of ports can accommodate more users with enhanced channel capacity as well as higher data rates [17]. In this regard, researchers have been focusing on the development of several eight-element antennas for various 5G applications [1,18,19,20,21,22,23,24]. However, all the above-specified literature lacks antenna flexibility and therefore the development of a flexible eight-element antenna for 5G mid-band needs attention.

Recently, a flexible eight-element antenna for this specific band has been designed on a flexible polyimide substrate [2]. The antenna has good radiation properties and a small footprint. However, the antenna’s low simulated bandwidth and gain limits its use in real-time MIMO applications. It is evident that there is a technical requirement for a low-profile multi-port flexible antenna that can accommodate a greater number of users and at the same time, exhibits a wider bandwidth, high efficiency, gain, and excellent MIMO diversity metrics.

Addressing the above-mentioned limitations, a flexible, eight-element antenna is proposed for the 5G mid-band. The antenna is fabricated on a PET substrate which makes the antenna highly flexible. To the authors’ best knowledge, an article that communicates the development and detailed study of a fabricated flexible eight-element antenna for the specific band is lacking in the literature. Being a part of the C-band spectrum, this band finds application in several communication infrastructures that includes the development of RF devices [25], resonators and filters [26], smartphone applications [27,28], and so on. The antenna has a footprint of 83 × 129 × 0.1 mm³ and a 4.5–5.5 GHz bandwidth with an average 4 dBi gain and 90% radiation efficiency throughout the operating range.

Novelty and Contributions:

• The proposed CPW-fed eight-element antenna consists of a self-isolating structure with a connected ground plane that offers isolation of 24 dB across the operating band.
• The antenna has a great bending profile with minimal influence on antenna properties, and it is validated using conformal analysis in both the x and y planes along a radius of 50 mm.
• Diversity performance of the proposed eight-element antenna is examined, and the results show good diversity values with ECC < 0.07, DG~10, MEG ratio~0, TARC < −10 dB, and ME < −0.5 that proves the appropriateness of the antenna for real-time diversity environments.
• Additionally, the proposed antenna’s ergodic channel capacity is investigated and compared with the ideal 8 × 8 MIMO antenna. The suggested antenna has a channel capacity ranging from 41.8 to 42.6 bps/Hz across its operational range. This is close to the optimum value, demonstrating the antenna’s benefits for high-quality MIMO performance.

The overall framework of this paper is as follows: A summary of the single-element design is given in Section 2. The dual and quad-element antenna are explained in Section 3. The proposed eight-element antenna and the associated analysis are elaborated on in Section 4. Section 5 and Section 6 include the results and discussion of the antenna and a conclusion, respectively.

2. Single-Element Antenna

2.1. Design Methodology

Figure 1 depicts the proposed single-element monopole antenna with a slotted CPW ground plane and a semi-arc stub integrated modified circular radiator. A flexible PET substrate with a dielectric constant of 3.4, thickness of 0.1 mm, and a loss tangent of 0.022 was utilized for this work. Copper was utilized in this study as the conducting material for the radiating parts. The antenna’s physical dimension was 40 × 30 × 0.1 mm³ (0.609λ × 0.457λ × 0.0015λ), with the wavelength λ calculated at 4.57 GHz. The optimal dimensions of the single-element antenna are given in

Table 1. Dimensions of the antenna parameters (in mm).

Ws	Ls	a	b	c	d	e	f	g	L	R1	R2	H
30	40	10	0.6	14	0.45	9.02	8	3	20	11	12	0.1

.

The antenna has evolved through a sequence of evolution stages. A slotted CPW ground plane and a circular monopole antenna make up the first stage. The antenna had a low impedance matching with an operating frequency from 4.3 to 5.1 GHz as in Figure 2. To increase the impedance matching and to further widen the bandwidth, modifications were made in the radiator by etching copper from it. This stage enhances the antenna’s impedance matching; however, the frequency of the antenna was shifted to a higher frequency as depicted in Figure 2. A semi-arc-shaped stub was engineered to the radiator to shift the frequency to a lower range with good impedance matching. With a bandwidth of 4.57–5.50 GHz, this stage offers the desired band of interest. For comparison, the gain over frequency of all the evolution stages as well as the radiation pattern of all stages calculated at the center frequency of 5 GHz is given in Figure 2b,c. From the figure, it is evident that the proposed single-element antenna offers wide bandwidth, good gain and radiation characteristics.

2.2. Parametric Analysis

Various parameters, like the feedline gap, width of the feedline, radius of the ground plane, and length of the stub, that help in achieving the desired wider bandwidth and good impedance matching were optimized using parametric analysis. However, the ground plane radius (R2) and the length of the stub are the critical parameters that help in achieving the desired bandwidth and therefore are the only ones highlighted in Figure 3. Increasing the ground plane’s radius alters the current direction, which lowers the antenna’s quality factor and boosts the operational bandwidth. The band of interest is achieved with the help of the stub’s length optimization. By increasing the stub length, the antenna’s effective length is changed, which moves the frequency to the lower range.

3. Dual and Quad-Element Antenna

The designed antenna is duplicated along the y-axis with an inter-element spacing of 3 mm to make a two-port antenna. To connect the ground, a rectangular stub is connected from edge to edge as shown in Figure 4. Figure 4b displays the dual-port antenna’s S-parameters. The antenna gives an isolation of 20 dB as shown in the figure.

The two-port antenna is further copied along the y-axis and duplicated with a spacing of 3 mm to form a quad-port antenna. As seen in Figure 5a, the antenna’s ground plane is connected through a stub. The antenna’s scattering parameters are depicted in Figure 5b,c. Over its operational range, the antenna displays a minimum average isolation of 20 dB.

4. Proposed Eight-Element Antenna

4.1. Antenna Design and Decoupling Mechanism

As seen in Figure 6, the proposed eight-element antenna with an overall dimension of 83 × 129 × 0.1 mm³ (1.245λ × 1.94λ × 0.0015λ) was created by mirroring the four-element antenna at a distance of 3 mm (0.045λ) along the x-axis. The antenna was initially connected with horizontal stubs as shown in Figure 6. This stage (antenna 1) gave an isolation of more than 16 dB throughout the bandwidth as displayed in the scattering parameters plot in Figure 7. To further improve the isolation between the antenna elements, three vertical stubs were connected to the ground plane in the second stage as shown in Figure 6. The scattering parameters of the proposed eight-element antenna are displayed in Figure 8. Incorporating these stubs altered the current path and improved the isolation to more than 24 dB throughout the bandwidth, which is better than that of stage 1.

The isolation enhancement of the antenna can be further investigated by examining the vector current distribution of the evolution stages. The vector current distribution of the antenna with horizontal stubs (antenna 1) as well as the proposed decoupling structure with vertical stubs is displayed in Figure 9a,b. The current distribution was examined by stimulating the first port (P1) and terminating all the other ports (P2–P8) as given in the figure. From Figure 9a, it is evident that when P1 is stimulated, the current is concentrated on the induced element and a portion of the current is seen on the adjacent elements, indicating mutual coupling between them. However, in Figure 9b, when P1 is excited and all the other ports are terminated, a negligible current appears in the adjacent element indicating better isolation among the antenna elements. The current is intense towards the feedline, radiator edges, and slotted ground plane of the excited element, as well as in the vertical stubs in the ground plane. Incorporating the proposed decoupling structure reduces the coupling current and enhances isolation by creating an out-of-phase current as indicated in Figure 9b. The vector current distribution indicated was calculated at a resonant frequency of 5.03 GHz. The configuration of the proposed eight-element antenna is given in Figure 10.

4.2. Equivalent Circuit Analysis

The lumped equivalent circuit model was used to study the simulated scattering properties of the antenna. Figure 11 provides the equivalent circuit representation of the antenna that was analyzed employing circuit theory and the impedance matching method [29,30]. The circuit model of the single antenna was first created and attached to the modeled lumped components of the decoupling structure using the coupling capacitors (CC1–CC8) to create the antenna’s whole equivalent circuit.

The parallel RLC component of each single element in the figure corresponds to the single resonance of the antenna which represents the real and imaginary part of the antenna impedance. The excitation of the circuit is given by 50 Ω ports as shown in the figure. The three LC combinations toward the center of the equivalent circuit represent the stub-integrated connected ground decoupling structure. The port-to-port coupling between the antenna elements was realized by tuning these combinations of inductance and capacitance (LC), which generate band stop characteristics across the entire operating range. The accurate tuning of these LC circuits accounts for the antenna’s input impedance, bandwidth, and isolation. The lumped parameters in the whole circuit were finally tuned using NI-AWR software to match the scattering parameters that were obtained from the HFSS software. Figure 11 gives the tuned values of lumped elements. The comparison of the reflection and transmission coefficients from HFSS and the equivalent circuitry is depicted in Figure 12a,b.

4.3. Conformal Analysis

Conformal analysis is one of the primary research areas related to the flexible MIMO antenna. The antenna characteristics tend to change when it is bent relative to different applications involving continuous bending and crumpling of the antenna [4]. As displayed in Figure 13, the suggested antenna is curved at a 50 mm radius over the x (vertical) and y (horizontal) axes. The antenna shows a slight deviation in its resonant frequency for both axis of the bend. It is important to note that the antenna still retained its bandwidth, proving that it offers a superior bending profile.

The CST Studio EM tool was used to model the bending of the antenna, and a 50 mm-radius cylindrical Styrofoam was used to validate the antenna results. The simulated bending results of the suggested antenna are displayed in Figure 14a–d. For brevity only, a few simulated scattering parameter results are shown. The antenna maintained both its transmission and reflection coefficients even after the bending circumstances, as seen in the picture. The measured scattering parameters of the proposed antenna under both bending scenarios are given in Figure 15a–d. The antenna gave a bandwidth of 4.48–5.6 GHz and 4.53–5.48 GHz for the x (vertical) and y (horizontal) axes, respectively, with a minimum isolation of 20 dB throughout the operational range as shown in Figure 15. Figure 16a,b analyses the proposed antenna’s co- and cross-polarization radiation characteristics in the principal planes (E and H) under both the x (vertical) and y (horizontal) axis bends calculated for the resonant frequency of 5.03 GHz. The figure indicates that the radiation characteristics remained excellent even after bending, hence validating the suggested eight-element antenna’s suitability for conformal applications.

The effect of antenna deformation on MIMO parameters such as ECC, DG, MEG, and ME due to both x-axis bending scenarios are displayed in Figure 17.

The effect of antenna deformation on MIMO parameters such as ECC, DG, MEG, and ME due to both y-axis bending scenarios is displayed in Figure 18.

5. Results and Discussion

Figure 19 illustrates the fabrication of the proposed eight-element antenna on a flexible PET substrate. Detailed analysis of the proposed antenna in terms of the S-parameters, radiation patterns, MIMO performances, and comparative analysis with existing works in the literature are discussed in the further section.

5.1. S-Parameters

The Anritsu S820E two-port VNA with a frequency range from I MHz to 40 GHz was used to validate the proposed antenna’s scattering properties as shown in Figure 20. Figure 21 shows the simulated and measured reflection coefficients and port isolation of the proposed antenna. The antenna covers the n79 band, as can be seen from the figure, with a measured −10 dB impedance bandwidth of 4.5–5.5 GHz. The port isolation of the antenna has a notable value of 24 dB throughout the operating bandwidth. The findings of the simulation and measurement agree with a small variation related to cable losses and fabrication tolerances.

5.2. Radiation Characteristics

The antenna’s radiation pattern measurements in an anechoic chamber are given in Figure 22a. The pattern was obtained by exciting one port and deactivating all the other ports with the matched condition for both the xz and yz planes. As shown in Figure 22b, the antenna had an average peak gain and radiation efficiency of 4 dBi and 90% within the working band of interest. Figure 23 displays the co- and cross-polar radiation characteristics of the principal planes at the 5.03 GHz resonance frequency. In the principal planes (E and H), the proposed antenna provided bidirectional as well as omnidirectional characteristics, respectively. A dual-ridge horn antenna that operates between 1–18 GHz was utilized in this study as the reference antenna. Figure 23 reveals that the proposed antenna exhibited cross polarization values of −22 dB in the E plane and −23 dB in the H plane, indicating the effective and desired antenna radiation.

5.3. MIMO Performance

The antenna was analyzed using MIMO metrics like envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), and multiplexing efficiency (ME) to examine MIMO diversity. Furthermore, the proposed eight-element antenna’s ergodic channel capacity was estimated and compared with the ideal 8×8 MIMO antenna, taking into consideration an SNR value of 20 dB. The above-mentioned investigations and the corresponding results are given in the upcoming sections.

ECC is a parameter that explains how well the individual elements are isolated within the MIMO system. This can be computed using the radiation pattern and Equation (1) [29].

$${\mathrm{E}\mathrm{C}\mathrm{C}}_{\mathsf{\rho }}={\displaystyle \frac{{\left|{\iint }_{4\mathsf{\pi }}\left[{\mathrm{E}}_1\left(\mathsf{\theta },\mathsf{\varphi }\right).{\mathrm{E}}_2\left(\mathsf{\theta },\mathsf{\varphi }\right)\mathrm{d}\mathsf{\Omega }\right]\right|}^2}{{\iint }_{4\mathsf{\pi }}{\left|{{\mathrm{E}}_1\left(\mathsf{\theta },\mathsf{\varphi }\right)|}^2\mathrm{d}\mathsf{\Omega }{\iint }_{4\mathsf{\pi }}\right|{\mathrm{E}}_2\left(\mathsf{\theta },\mathsf{\varphi }\right)|}^2\mathrm{d}\mathsf{\Omega }}}$$

(1)

Here, representation of the electric field product is

$${\mathrm{E}}_1\left(\mathsf{\theta },\mathsf{\varphi }\right).{\mathrm{E}}_2\left(\mathsf{\theta },\mathsf{\varphi }\right)={\mathrm{E}}_{\mathsf{\theta }1}\left(\mathsf{\theta },\mathsf{\varphi }\right){\mathrm{E}}_{\mathsf{\theta }2}^{\mathrm{*}}\left(\mathsf{\theta },\mathsf{\varphi }\right)+{\mathrm{E}}_{\mathsf{\varphi }1}\left(\mathsf{\theta },\mathsf{\varphi }\right){\mathrm{E}}_{\mathsf{\varphi }2}^{\mathrm{*}}\left(\mathsf{\theta },\mathsf{\varphi }\right)$$

The value of ECC should be smaller than 0.5 to provide an efficient MIMO environment. Figure 24a shows the ECC computed using the 3D radiation pattern and the value falls to 0.07 for the operating frequency range which ensures the effectiveness of the MIMO. DG, on the other hand, is the metric that evaluates how desirable the diversity is, shown in Figure 24b, and can be computed using the correlation coefficient and Equation (2) [31].

$$\mathrm{D}\mathrm{G}=10\sqrt{1-{\mathrm{E}\mathrm{C}\mathrm{C}}^2}$$

(2)

MEG is the ratio between the accepted and incident power of the MIMO elements concerning the isotropic antenna and is shown in Figure 24c. ME is the parameter that describes the relationship between each component of the MIMO system and the same has been shown in Figure 24d. Conversely, TARC explains the MIMO antenna performance and is depicted in Figure 24e. It provides information about the power levels of the incident and reflected waves. These parameters can be computed using Equations (3)–(5) [31].

$${\mathrm{M}\mathrm{E}\mathrm{G}}_{\mathrm{i}}=0.5\left(1-{\mathsf{\Sigma }}_{\mathrm{j}=1}^{\mathrm{M}}\left|{\mathrm{S}}_{\mathrm{i}\mathrm{j}}\right|\right)$$

(3)

$$\mathrm{T}\mathrm{A}\mathrm{R}\mathrm{C}=\sqrt{{\displaystyle \frac{\left(\right|{\mathrm{S}}_{\mathrm{i}\mathrm{i}}+{\mathrm{S}}_{\mathrm{i}\mathrm{j}}{\mathrm{e}}^{\mathrm{j}\mathsf{\theta }}{|}^2)+(|{\mathrm{S}}_{\mathrm{j}\mathrm{i}}+{\mathrm{S}}_{\mathrm{j}\mathrm{j}}{\mathrm{e}}^{\mathrm{j}\mathsf{\theta }}{|}^2)}{2}}}$$

(4)

$$\mathrm{M}\mathrm{E}=\sqrt{{{\mathsf{\eta }}_1\mathsf{\eta }}_2(1-|{\mathsf{\rho }}_{\mathrm{i}\mathrm{j}}\left|\right)}$$

(5)

Figure 24a–e displays the diversity performance of the proposed eight-element antenna. From the figure, it can be inferred that the proposed antenna provides good diversity values with ECC < 0.07, DG ~ 10, MEG ratio ~ 0, TARC < −10 dB, and ME < −0.5 throughout the operating bandwidth which implies that the antenna is appropriate for MIMO scenarios.

5.4. Channel Capacity

The proposed eight-element MIMO system’s channel capacity (CC) is calculated using the Shannon formula given in Equation (6) [4,32].

$$\mathrm{C}=\mathrm{k}{\mathrm{l}\mathrm{o}\mathrm{g}}_2\left[\mathrm{d}\mathrm{e}\mathrm{t}\left(\left[\mathrm{I}\right]+\mathsf{\eta }{\displaystyle \frac{\mathrm{S}\mathrm{N}\mathrm{R}}{\mathrm{k}}}\left[\mathrm{H}\right]\left[{\mathrm{H}}^{\mathrm{*}}\right]\right)\right]$$

(6)

Here, SNR represents the mean signal-to-noise ratio, $I$ denotes the identity matrix, $\left[H\right]$ is the channel matrix, $\left[H^{\mathrm{*}}\right]$ is the Hermitian transpose matrix, and k is the rank of the $\left[H\right]\left[H^{\mathrm{*}}\right]$ matrix.

MIMO channel models utilizing ray tracing and their associated channel models are normally used for calculating channel capacity [4]. The correlation matrix and the simulated efficiency of the modeled MIMO system were therefore utilized to calculate the channel capacity. Figure 25 shows that the estimated capacity of the eight-element MIMO antenna lies between 41.8 and 42.6 bps/Hz throughout the frequency of operation, which was estimated by norming over 10,000 distinct Rayleigh fading realizations concerning 20 dB SNR in an identically distributed propagation scenario [1,4]. The optimal channel capacity of 8 × 8 MIMO and single-input single-output (SISO) systems is provided for easier comparison. The estimated CC of 41.8–42.6 bps/Hz of the eight-element antenna is very close to the optimal capacity of 46 bps/Hz of 8 × 8 MIMO systems, indicating that the performance is sufficient for satisfactory performance in real-time scenarios.

5.5. Comparative Analysis

The following section compares the proposed eight-element antenna performance with other Sub-6 GHz eight-element antennas in the literature. Compared to the presented antenna, the bandwidth of the antenna in [19] is wider. However, the overall size of the antenna is very large, with a lower isolation. The antenna proposed in [20] provides a very low isolation than the proposed antenna even while having a comparatively low profile. The overall antenna size of the antennas presented in [24,31] is large with a low isolation value even though the bandwidth of the antenna is satisfactory. References [20,31] discuss the channel capacity of the corresponding antennas, but it is evident that the CC of the proposed antenna is better than both of them. All these above-mentioned antennas are non-flexible in nature. Recently, a flexible eight-element antenna has been proposed in [2] for the specific band. However, the antenna has a lower bandwidth and lower isolation values than the proposed eight-element antenna.

Table 2. Comparative analysis of the proposed antenna with other eight-element antennas in the literature.

Ref.	Antenna Size (mm3)	Antenna Size (λ 3)	Element Spacing(λ)	No. of Ports	Bandwidth (GHz)	Isolation (dB)	ECC	Flexible	CC (bps/Hz)
[2]	95 × 65 × 0.2	0.996λ × 0.660λ × 0.002λ	0.06λ	8	3.05–3.74	15	<0.1	Yes	-
[19]	150 × 75 × 7	1.650λ × 0.825λ × 0.077λ	0.208λ	8	3.3–6	18	<0.05	No	-
[20]	103.8 × 68 × 7	1.124λ × 0.736λ × 0.0076λ	0.180λ	8	3.25–5.93	10	<0.1	No	39
[24]	150 × 75 × 7.8	1.650λ × 0.825λ × 0.086λ	0.328λ	8	3.3–6	12.6	<0.31	No	-
[31]	150 × 75 × 7	1.55λ × 0.775λ × 0.072λ	0.196λ	8	3.1–6	16	<0.02	No	41.1
Prop	83 × 129 × 0.1	1.245λ × 1.94λ × 0.0015λ	0.045λ	8	4.5–5.5	24	<0.07	Yes	42.6

indicates that the proposed antenna outperforms the existing eight-element antenna in the specific band in terms of flexibility, satisfactory bandwidth, improved isolation, good MIMO diversity metrics, and enhanced channel capacity values.

6. Conclusions

This article presents a novel eight-element antenna for the Sub-6 GHz band. With an average peak gain of 4 dBi and efficiency of 90% across the operational spectrum, the antenna has a measured impedance bandwidth of 20% (4.5–5.5 GHz). The proposed antenna offers notable isolation of 24 dB throughout the operating range. The MIMO performance is satisfactory with good MIMO diversity values of ECC < 0.07, MEG ratio ~ 0, TARC < −10 dB, DG ~ 10, and ME < −0.5. The calculated peak channel capacity over bandwidth value of 42.6 bps/Hz is very close to the ideal 8 × 8 MIMO system. Further, the conformal analysis of the proposed antenna was investigated and the effect of antenna deformation on the performance characteristics of the antenna was investigated. The proposed antenna shows very good performance that extends the application possibility of the proposed antenna for wearable applications in the specific band. Through the performance evaluation and the corresponding results obtained, it can be concluded that the presented antenna is a suitable candidate for Sub-6 GHz MIMO scenarios. As a future direction, different decoupling structures and gain enhancement techniques can be investigated to further improve the performance of the proposed MIMO antenna.