Introduction

In the recent past, Intelligent Transport Systems (ITS) in vehicular communication have gained significant attention from researchers and academia. This interest is driven by the advancements in vehicular communication, which have improved traffic efficiency and road safety, as well as the emerging concepts of smart cities and Internet of things (IoT)1,2. Vehicular communications for future technologies are characterized by vehicular-to-vehicular (V2V), vehicular-to-interface (V2I), vehicular-to-network (V2N), and vehicular-to-everything (V2X) communication3,4. V2X is the most interesting and emerging technology that facilitates communication among vehicles and other entities in smart transportation system5. Federal Communication Commission (FCC) allocated the band spectrum of 5.9 GHz while IEEE standard 802.11p-2010 proposed the band spectrum ranging from 5.85 GHz to 5.925 GHz for V2X communication and Dedicated Short-Range Communication (DSRC)6.

Bendable and flexible electronic devices are gaining significant attention owing to their applications in wearable devices and conformal portable gadgets7,8. Moreover, for vehicular communication systems, flexible devices are advantageous over other devices due to the fact that they can place on any part of the vehicle. Furthermore, these devices are the perfect fit for V2X communication due to their ease of integration with the human body owing to the advantage of flexibility9,10. Additionally, these devices can be used for smart and compact short-range communication systems operating in the dedicated frequency spectrum11.

Antenna is one of the critically important components of electronic devices and communication systems12. A flexible and bendable antenna should be designed to operate over 5.9 GHz used for V2X communication11,13. For this purpose, many antennas are designed and proposed using various substrate materials, however, the traditional materials have limitations and can’t be bent to the full range. Thus, more efforts have been put into exploring new materials for this purpose. As a result, conformal antennas were designed using polymers such as PET, polyimide, and PDMS14,15,16,17. Additionally, these antennas must possess high gain and fast communication in addition to other parameters not limited to compact size and simplified structural configuration18,19,20,21.

For V2X communication systems, the MIMO antennas are widely used due to the advantages of high data rate, low latency rate, and diverse radiation pattern characteristics22,23,24. This cutting-edge technology has the potential to alter vehicular communication system with surrounding vehicles and environments25. Moreover, the diversity in radiation pattern improves spectral efficiency and addresses the challenges arising from highly dynamic and unpredictable nature of vehicular environments12,26,27. Thus, effective communication in V2X systems is possible by achieving a high-gain and beamforming antenna capable of pattern diversity28,29.

Considering the aforementioned challenges associated with V2X communication systems and wearable devices, a flexible and compact antenna is proposed in this article. The optimized antenna is further extended to a 2-Port MIMO antenna to achieve high data rates and fast communication. The detailed comparison of proposed MIMO antenna with state-of-the-art literature work is provided in “Comparison with Literature” section. The results from the comparison study with literature show that proposed antenna is novel in terms of the key features below.

  • The proposed antenna has a novel geometry with compact size using a novel material (MWCNT composite PDMS) for radiative portions.

  • The operational band covers three frequency spectrums, which have potential applications for WLAN, V2X and WiFi-6E.

  • The antenna offered acceptable values of various parameters, which make it suitable for both wearable and vehicular applications. `

The rest of the article is divided into five sections, where the single element of the antenna and its performance parameters are presented in “Single element of antenna” section. In “Two–Port MIMO configuration of the proposed antenna” section, MIMO characterization is explained along with simulated results and experimental findings. Moreover, for the targeted applications of the antenna, wearable and V2X communications are analyzed in “Antenna Applications” section. The performance parameters of proposed antenna are compared with recent published work in "Comparison with Literature" section. The proposed work is concluded accompanied by references in "Conclusion" section.

Single element of antenna

Antenna design

The single element of the proposed conformal antenna is depicted in Fig. 1. The structure of a single element of the proposed bendable antenna contains a microstrip feedline and a square-shaped patch loaded with two inverted L-shaped arms. The microstrip feedline technique is used as it is easy to handle during fabrication and is optimized for 50 Ω impedance matching. The two L-shaped arms are loaded to the square-shaped patch to improve impedance bandwidth as well as improved matching. The single element of the antenna has an overall size of TX × TY = 32 mm × 35 mm. Polydimethylsiloxane (PDMS) is used as a substrate material having relative permittivity, loss tangent, and thickness of 2.77, 0.012, and 2.5 mm, respectively. The selection of PDMS as a substrate material is due to its advantages of flexibility, lightweight, compatibility, chemical stability, and ease of fabrication30. The radiating element and ground planes are constructed by using the composite of MWCNT-PDMS, having a conductivity of 105 Siemens/m and a thickness of 1 mm. Moreover, an EM software tool, CST, is utilized to design and analyze various performance parameters of the proposed antenna. The optimized parameters of the proposed antenna are: TX = 32; TY = 35; P = 12; x1 = 12.5; y1 = 1; x2 = y2 = 10; x3 = y3 = 2. (All units are in mm).

Fig. 1
figure 1

The geometrical configuration of a single element of the proposed antenna (a) Front view (b) Perspective view.

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Antenna design stages

Figure 2 represents the design stages of the proposed antenna and its outcomes in terms of |S11|. It can be seen from the figure that a microstrip feedline antenna (step 1) is designed to have a square-shaped patch that operates at 6.02 GHz. The selection of material is based on the applications of the antenna, whereas the dimensions of the patch are obtained by using patch antenna equations provided in31. To improve the impedance bandwidth and matching of the proposed antenna, an L-shaped stub is loaded into the square-shaped stub. By loading the additional stub, additional reactive load is introduced which consequently reduces the return loss of the antenna. The antenna in step 2 offers the |S11|< − 10 dB impedance bandwidth of 5.95–6.20 GHz, having a resonance at 6.1 GHz. In step 3, another inverted L-shaped stub is loaded to the antenna, which further improves impedance matching together with a slight shift in resonant frequency. The proposed antenna is obtained after the third designing step having a broadband range 5.78–6.28 GHz that is 8.5% of the central frequency. The design evolution steps of the antenna along with its impact on the S-parameter is given in Fig. 2.

Fig. 2
figure 2

Design steps to construct the single element of the proposed antenna and its outcomes in terms of S-Parameter.

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Antenna results

Various performance parameters of the unit element antenna including S11, gain, radiation efficiency, surface current distribution, and radiation pattern are analyzed and compared with experiment results. The detailed information about fabrication and measurement processes is given in “Two–Port MIMO configuration of the proposed antenna” section, whereas the antenna single element performance is validated by using Keysight ENA Network Analyzer, having modal number E5053A. Furthermore, the anechoic chamber is utilized to study the far-filed characteristics of antenna.

S11

Figure 3 shows the comparison between the tested and simulated S-parameter of the proposed single element of the antenna and the hardware prototype photo. It can be seen from the figure that the single element of the proposed antenna offers a bandwidth of 5.78–6.28 GHz with a resonant frequency of 6 GHz. The antenna covers IEEE 802.11 (Wi-Fi) and IEEE 802.16 (WiMAX) ranges from 5.725 to 5.875 GHz for WLAN and industrial applications. It also covers IEEE 802.11p (DSRC, V2X) range from 5.85 to 5.925 GHz for V2X, V2V, V2I, and V2N applications for smart transportation and traffic safety32. Moreover, the proposed antenna also covers the Wi-Fi 6E band operating above 6 GHz for point-to-point communication and fixed wireless broadband. The simulated results of the proposed single element of the antenna show good agreement with the tested prototype results. The verification of simulated results targeting aforementioned applications make the proposed antenna a suitable candidate for future wireless IoT devices used for vehicular communication and Wi-Fi services.

Fig. 3
figure 3

Tested and simulated the S-parameter results of a single element of the antenna.

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Gain and radiation efficiency

Figure 4 represents the gain and radiation efficiency of the proposed single antenna element. It is noted from the figure that a single element of the antenna offers a peak value of gain of 5.15 dBi at the resonant frequency of 5.80 GHz. The antenna gain remains stable from 5.75 GHz to 6.1 GHz, while the drop in gain is observed from 6.1 to 6.27 GHz. The lowest value of gain is noted at 6.25 GHz, where the gain is 3.45 dBi. This behavior of gain is due to the conductor losses and lower effective aperture. Overall, the value of gain is high and acceptable for practical applications. The tested results also support the simulated outcomes as given in Fig. 4a.

Fig. 4
figure 4

(a) Tested and simulated Gain of the proposed antenna single element, (b) Radiation efficiency, (c) 3D Gain.

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The radiation efficiency of the proposed antenna is given in Fig. 4b. It can be seen that the antenna offers the highest value of radiation efficiency of > 83% at 6.0 GHz. The lowest value of radiation efficiency at the operational band is 79.5% at 6.25 GHz, which is still acceptable for practical applications. Moreover, Fig. 4c shows the 3D polar plot of the antenna at the resonance frequency of 5.94 GHz. It can be seen that the antenna offers a gain of 4.51 dBi at resonance frequency having broadside radiation pattern.

Radiation pattern

The tested and simulated radiation patterns of the proposed antenna at three different frequencies of 5.8 GHz, 6.0 GHz, and 6.1 GHz are given in Fig. 5. It can be seen that the proposed antenna offers a stable and broadside radiation pattern at both the E and H planes for all three targeted frequencies. The offered radiation patterns indicate the high gain and directivity of the antenna. The prototype’s tested results provide good consistency with the simulated radiation patterns, which makes the proposed single-element antenna a suitable candidate for the mentioned applications.

Fig. 5
figure 5

Tested and simulated radiation patterns of the proposed single-element antenna at various operational frequencies.

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Surface current distribution

The surface current distribution of the proposed single-element antenna is studied at 5.8 GHz, 6.0 GHz, and 6.1 GHz, as shown in Fig. 6. At 5.8 GHz, the maximum amount of current density, 138 A/m, is observed at the lower side of the square-shaped patch along with the feedline, and a small portion of the square patch upper side. In the case of 6.0 GHz, the feedline and edges of the square-shaped patch, the high amount of current is noted in the left L-shaped stub. At 6.1 GHz, in the left inverted L-shaped stub and some part of the square-shaped patch, the maximum current is noted, as seen from the given figure.

Fig. 6
figure 6

Surface current distribution of proposed antenna single element at different operational frequencies.

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Conformal analysis

To verify the flexibility of the proposed antenna, it is cylindrically bent. The use of PDMS as the substrate material and MWCNT-PDMS for the conductive parts makes it highly flexible without effecting the structure of the antenna. The proposed antenna is bent with radii of 50 mm and 30 mm, and results are compared with an unbent antenna, as illustrated in Fig. 7. When the antenna is not bent, it offers a bandwidth of 5.78–6.28 GHz. Bending the antenna over a 50 mm cylinder results in a slight shift in resonance frequency and bandwidth, offering a bandwidth of 5.81–6.21 GHz with a resonance frequency of 6.02 GHz. On the other hand, when the antenna is bent over a 30 mm cylinder, the return loss of the antenna is affected in addition with a slight shift in the resonance band, resulting in a bandwidth of 5.88–6.22 GHz, as depicted in the figure. Overall, the antenna performance remains stable with minor and negligible shifts in resonance frequency.

Fig. 7
figure 7

Conformal analysis results of the proposed antenna with various bending radii.

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Two–port MIMO configuration of the proposed antenna

In “Single element of antenna” section, it is clear that the antenna offers strong performance parameters which increase its potential for various wireless applications. The results are also verified after fabricating the hardware prototype, which shows good agreement with simulated results. After verification of antenna performance in terms of a single element, the two-port MIMO configuration is constructed for fast communications, high data rate, and low latency applications. In this section, the design of a two-port MIMO antenna is discussed together with its performance parameters.

Antenna geometry and measurement

The two-port MIMO configuration is constructed in such a way that the second element of the antenna is placed at the orthogonal position of the first element. The gap (g) between the two antenna elements is 8 mm. The MIMO antenna has an overall size of ML × MW = 70 mm × 35 mm. The proposed two-port MIMO antenna is also constructed of the same materials as the single-element antenna given in “Antenna design” section. Each element of the MIMO antenna has the same design parameters as the single-element antenna. The geometrical configuration of the proposed MIMO antenna is given in Fig. 8a.

Fig. 8
figure 8

(a) Geometry of the proposed two-port conformal MIMO antenna (b) Fabricated prototype and measurement setup of the proposed MIMO antenna.

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The hardware prototype of the proposed antenna is fabricated as given in Fig. 8b and tested to verify the simulated outcomes. PDMS is prepared for the substrate layer while CNT-PDMS is prepared for the conductive and ground layers. The materials are manufactured after following the standard procedure given in40,32,33. The proposed antenna is fabricated in the lab by using a mold casting technique which comprises the following steps. The step-by-step antenna fabrication stages are provided in Fig. 9.

  • Step 0 Initially, 3D mold is manufactured in 3D printer, which has the replicated geometry of the antenna as well as the same size as the antenna substrate.

  • Step 1 Liquid MWCNT-PDMS is put into the 3D mold to get the radiative part and then kept in an oven at 60 °C for 4 h.

  • Step 2 PDMS liquid is applied over the radiative part (MWCNT-PDMS) to construct the substrate layer. Then, the mold is again placed in the oven at 60 °C for 5 h to cure the PDMS layer.

  • Step 3 Finally, MWCNT-PDMS is applied in the 3D mold to construct the ground layer. Then, the mold is again placed in the oven at 60 °C for 4 h to cure the ground layer34.

  • Step 4 Once cured and solidified, the antenna sample is peeled out from the 3D mold. Then the SMA connector is connected to the feedline of the antenna by using conductive glue. The conductive glue (Electric Paint made by Bare Conductive) is used to connect the connector and radiative portion of proposed MIMO antenna.

Fig. 9
figure 9

The fabrication process of the proposed antenna.

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Reflection and transmission coefficient

Keysight ENA Network Analyzer E5063A (ranging from 100 kHz to 6.5 GHz) is used to measure the performance of the antenna. The tested and simulated S-parameter results of the proposed antenna in terms of transmission and reflection coefficient are given in Fig. 10. It can be noted that the antenna offers 5.79–6.22 GHz from both ports of the antenna. A slight and negligible difference is noted between reflection coefficients of S11 and S22, which may be due to the placement of the antenna elements. The proposed antenna also offers excellent values of transmission coefficient with a maximum value of less than -26 dB and a minimum value of less than − 40 dB in the operational region. This value of mutual coupling is considered good as no parasitic patch or metasurface is used, and these are obtained by self-decoupling. Moreover, the measured results also show good consistency with simulated results, as shown in Fig. 10. The outcomes obtained in terms of bandwidth and the good agreement between tested and simulated results make the proposed MIMO antenna a suitable candidate for vehicular communication and Wi-Fi services.

Fig. 10
figure 10

Tested and simulated reflection and transmission coefficients of the proposed MIMO antenna.

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Equivalent circuit model

The equivalent circuit model (ECM) of the proposed two-port MIMO antenna is given on Fig. 11. It can be seen that in the given circuit each element of the MIMO antenna is represented by RLC components which are series and parallel connected. The software tool ADS is used to construct and analyze the circuit. The optimized value of circuit parameters (Capacitors, Inductors and Resisters) are given in Table 1. The outcomes of the ECM in terms of the S-parameter are compared with the antenna S-parameter where a strong similarity is achieved, as depicted in Fig. 11b.

Table 1 Optimized values of circuit parameters.
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Fig. 11
figure 11

(a) Equivalent circuit model (ECM) of the proposed antenna (b) S-parameter comparison of the circuit with simulated results.

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The resonant frequency can be obtained from the proposed LC circuit are calculated by using the following relationship35:

$$f_{1} = \frac{1}{{2\pi \sqrt {L_{1} C_{1} } }}$$

Here the value of inductor (L) and capacitor (C) are calculated with the help of the following equations:

$$L = \frac{\mu o\mu rWphp}{{Lp}}$$
$$C\frac{\varepsilon o\varepsilon rWsLs}{{hs}}$$

where Wp and Lp are the width and length of the antenna patch, hp is the thickness of the antenna and µ is the permeability of surrounding materials. Ws and Ls are the width and length of the substrate, hs is the thickness of the substrate and \(\varepsilon\) is the permittivity of the substrate.

3D gain of MIMO antenna

Antenna gain is one of the most important parameters of an antenna. It shows the transmission ability of antenna radiation in a particular direction and strength in various directions. In the case of the MIMO antenna, high gain indicates good transmission efficiency which increases the overall system capacity and performance. The 3D gain plot of the proposed antenna generated by using EM software tool CST is given in Fig. 12. It can be seen that the antenna offers a peak gain value of 4.71 dBi at a resonant frequency of 5.95 GHz.

Fig. 12
figure 12

3D gain plot of the proposed conformal MIMO antenna at 5.95 GHz. (This figure is generated by using software CST given in36).

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Measured and simulated radiation pattern

The radiation pattern of the MIMO antenna, when either port is excited, is studied at 6.0 GHz and compared with the measured results. The E-plane and H-plane radiation patterns are given in Fig. 13, which shows that the antenna offers a broadside pattern at 6.0 GHz. It is also observed from the figure that the radiation patterns dominate at 0° angle and offer good agreement between tested and simulated results. The proposed MIMO antenna can produce high gain and directivity. The offered results and consistency of tested and simulated results make the proposed MIMO antenna a suitable candidate for WLAN and V2X applications.

Fig. 13
figure 13

Tested and simulated radiation pattern of proposed conformal MIMO antenna at 6.0 GHz.

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Surface current distribution

The distribution of surface current plays a role in determining the impedance matching, radiation characteristics, and mutual coupling in the case of the MIMO antenna. The current distribution of the proposed MIMO antenna at the resonant frequency of 6.0 GHz is depicted in Fig. 14. It can be noted from the given figure that the surface current is analyzed for the one element of the antenna that is excited. The significant amount of current accumulation along the edges and the discontinuities suggests strong radiation characteristics in these regions.

Fig. 14
figure 14

Surface current distribution of proposed conformal MIMO antenna at 6.0 GHz.

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MIMO parameters

To analyze the performance of the MIMO antenna two key performance parameters, envelop correlation coefficient (ECC) and diversity gain (DG) are studied, as given in Fig. 15. ECC evaluates the correlation between antenna elements based on their radiation patterns and determines how independently the antenna elements operate in a multipath environment, directly impacting the system’s diversity gain and overall performance. A lower ECC value signifies better isolation between elements, reducing interference and improving spatial multiplexing efficiency. For optimal MIMO operation, ECC values ideally be close to zero and practically it must be less than 0.2, ensuring minimal correlation between antenna elements. The ECC is evaluated using the expression widely used and discussed in37. Figure 15a shows that the proposed MIMO antenna offers an ECC value of less than 0.1, which is well below the acceptable threshold.

Fig. 15
figure 15

MIMO parameters of proposed two-port MIMO antenna (a) ECC (b) DG.

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DG quantifies the improvement in signal reliability by leveraging multiple antenna elements. It represents the reduction in transmission power needed to achieve a specific signal quality in a multipath environment. A higher DG value indicates better diversity performance, leading to improved signal reception and reduced fading effects. Ideally, a MIMO antenna should provide a DG of 10 dB to ensure optimal diversity performance. However, in practical scenarios, a slightly lower value is still acceptable. As depicted in Fig. 14b, the proposed MIMO array antenna achieves a DG of approximately 9.95 dB, which is very close to the ideal value. The near-ideal DG value confirms the efficiency of the proposed design in ensuring stable performance, making it suitable for high-reliability MIMO applications.

Antenna applications

The performance of the single element and the two-port MIMO antenna have been studied where the results are also verified by experimental tests with the fabricated hardware prototypes. Due to the features of lightweight, compactness, flexibility, operational band, and high gain, the proposed antenna is potentially suitable for numerous wireless applications. Based on the operational bandwidth, the proposed antenna can be utilized for wearable devices in WLAN applications and smart IoT devices in vehicular applications. Figure 16 shows the overview of the potential applications of the proposed antenna based on its operational bandwidth. The results in support of these applications are given in the two sub-sections below.

Fig. 16
figure 16

Applications for the proposed MIMO antenna.

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Wearable applications

To study its performance for wearable applications, proposed MIMO antenna prototype is placed on the chest and back of a human body phantom by using EM software Sim4Life where the antenna’s specific absorption ratio (SAR) is studied accompanied by its gain, as given in Fig. 17.

Fig. 17
figure 17

Placement of the proposed antenna on the front and back sides of a human body model. (This figure is generated by using software Sim4Life given in38).

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The SAR analysis of the proposed MIMO antenna is performed by following the standard 1g and 10g of tissue. It can be seen from Fig. 18, that the proposed MIMO antenna offers a maximum SAR value of 0.17 W/kg when it is placed on human chest having 1-g tissue sample. On the other hand, the maximum SAR value drops to 0.04 W/kg when assessed over a 10g tissue sample in the same area. Because electromagnetic radiation is distributed and dissipated over a larger mass, there is a decrease in SAR as tissue volume increases.

Fig. 18
figure 18

SAR analysis of proposed MIMO antenna at 6 GHz (a) On the chest of the human body over 1g and 10g tissue (b) On the back of the human body over 1g and 10g tissue.

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Similarly, when the antenna is placed on the backside of the human body, the maximum SAR value measured for a 1g tissue sample is recorded at 0.16 W/kg. For a 10g tissue sample in the same region, the maximum SAR value is observed to be 0.052 W/kg. These results indicate that SAR values vary based on both the placement of the antenna and the mass of the tissue under consideration. The slight differences in SAR between the chest and back can be attributed to variations in tissue composition, density, and proximity to vital organs. This analysis is essential for ensuring compliance with safety standards and optimizing antenna designs for minimal human exposure while maintaining efficient performance. According to Federal Communication Commission (FCC) and Institute of Electrical Electronic Engineering (IEEE) the standard values of SAR1g and SAR10g limits are 1.6 W/Kg and 2 W/Kg, respectively39. The proposed antenna offers the SAR values under the acceptable ranges, which makes the proposed design suitable for wearable applications.

Likewise, the proposed MIMO antenna gain is also analyzed by placing it on the front chest and back of the human body model. It can be seen from Fig. 19 that the proposed antenna exhibits a gain of 7.6 dB when placed on the model’s front chest. This indicates that the antenna efficiently radiates energy in this placement, likely due to the interaction between the antenna and the surrounding tissue. The proposed antenna gain reported 6.9 dB when positioned on the back of the human body model. This gain reduction may be attributed to differences in tissue composition, variations in dielectric properties, and potential absorption effects caused by the human body.

Fig. 19
figure 19

On-body gain of the proposed antenna by placing on (a) Chest, (b) Back. (This figure is generated by using software Sim4Life given in38).

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Vehicular applications

From the results and discussion in “Two–Port MIMO configuration of the proposed antenna” section, it is verified that the proposed antenna operates at around 5.725–5.85 GHz band, which is dedicated to vehicular communications. To claim the proposed antenna suitable for vehicular communication, the MIMO antenna was placed on a car model to analyze the antenna radiation pattern as given in Fig. 20. The antenna 3D polar pattern and 2D pattern are analyzed to validate the performance of the proposed MIMO antenna over a car model. These simulations are carried out by using CST software tool. It can be noted that the proposed MIMO antenna is highly directional, and a broadside radiation pattern is offered with a maximum gain of 5.5 dBi, which is suitable for vehicular communications. Figure 20c displays the 2D radiation pattern of the proposed MIMO antenna, by using a car model. The results show that the antenna offers stable radiation patterns with high gain in broadside for both E and H planes. These results make the proposed antenna suitable for vehicular communications.

Fig. 20
figure 20

(a) Proposed MIMO antenna placed on the car model. (b) 3D radiation pattern for two-port antenna. (c) 2D Radiation plots of antenna. (This figure is generated by using software CST given in36).

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Comparison with literature

In Table. 2, the comparison of the proposed antenna is given with recently published work that operates at the same frequency band targeting similar applications. The comparison is carried out in terms of size, operational bandwidth, peak gain, minimum isolation, and ECC. The substrate material used for various designs is also added in comparison table. It can be seen that the proposed antenna offers a compact size as compared to the literary work except27. Although the antennas reported in23,24,25,26 and28 offer a high gain as compared to the proposed antenna but suffer from either larger geometrical size or narrow bandwidth. The gain offered by the proposed work is small compared to these reported works, but it is under acceptable range (> − 3 dBi). Furthermore, the proposed antenna outperforms them with respect to other parameters that are compact size, wide operational bandwidth, low-profile, good values of isolation and ECC. Besides these performance parameters, the proposed antenna is also studied for conformal analysis, narrows and validates its potential for wearables by analyzing it on human body and vehicular models, where the proposed antenna offers stable performance analysis. The material utilized for radiative part of antenna (MWCNT-PDMS) is also the novel approach to study flexible antenna for wearable and vehicular applications.

Table 2 Comparison of the proposed MIMO antenna with recently published conformal antennas in the literature for V2X applications.
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Conclusion

A PDMS and MWCNT-based two-port MIMO antenna was designed and investigated in this research article. Initially, a single element of antenna is designed which consists of a square-shaped patch loaded with L-shaped stubs, which operates at 5.78–6.28 GHz. The two-port MIMO configuration is achieved by placing antenna elements orthogonal to each other. The key performance parameters of the proposed MIMO antenna were studied and verified using hardware prototype. The simulated results show good agreement with the tested results, which verifies the performance stability of the proposed antenna. The equivalent circuit model of the proposed antenna is also presented to provide the insight of the antenna along with its comparison with EM model results. Based on antenna operational bandwidth, the proposed MIMO antenna is proposed for wearable and vehicular applications where the antenna SAR analysis is studied by placing it on a human model and for vehicular applications antenna is placed on a car model. The proposed antenna offers low SAR values of 0.17 W/Kg and 0.16 W/Kg on 1g, and 0.04 W/Kg and 0.052 W/Kg placed on 10g tissue when placed on the chest and back, respectively. Moreover, the proposed MIMO antenna offers a gain of 7.6 dBi on the chest and 6.9 dBi on the back of the human model. Furthermore, the antenna also offers stable performance when simulated with CAR model. Finally, the performance parameters of the proposed antenna were also compared with recent published work and the outcomes validate the high potential of the proposed system for compact wearable devices as well as for vehicular communications.