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Current research efforts are directed towards utilizing polymers and biodegradable materials to develop innovative wireless devices for emerging applications within the sub-6 GHz spectrum. This study seeks to enhance the electrical and radiation characteristics of antennas while ensuring favorable environmental properties such as flexibility and Specific Absorption Rate (SAR). To this end, a comparative analysis of two flexible rectangular microstrip antennas constructed from novel polymer-based substrates is presented. One antenna uses a flexible composite substrate of polydimethylsiloxane (PDMS) embedded with carbon nanotubes (CNT), while the other employs a biodegradable polymer composite substrate made of polycaprolactone (PCL) reinforced with CNT. Results indicate that the PCL-CNT antenna surpasses the PDMS-CNT antenna in performance, in both flat and bent conditions. Specifically, at 2.4 GHz, the PCL-CNT antenna achieved a gain of 4.46 dBi and an efficiency of 0.70, compared to a gain of 3.94 dBi and an efficiency of 0.61 for the PDMS-CNT antenna. Furthermore, the superior performance of the PCL-CNT biodegradable polymer composite antenna suggests its potential for IoT applications and wireless communications, combining effective on-body usage with minimal environmental impact. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of side lobe interference in 5G networks by proposing a unique collaborative beamforming strategy based on Deep Q-Network (DQN) reinforcement learning. Our method, which operates in the sub-6 GHz band, maximizes beam steering and power management by using a two-antenna system with DQN-controlled phase shifters. We provide an OFDM cellular network environment where inter-cell interference is managed while many base stations serve randomly dispersed customers. In order to reduce interference strength and improve signal-to-interference-plus-noise ratio (SINR), the DQN agent learns to modify the interference angle. Our model integrates experience replay memory with a long short-term memory (LSTM) recurrent neural network for time series prediction to enhance learning stability. The outcomes of our simulations show that our suggested DQN approach works noticeably better than current DQN and Q-learning methods. In particular, our technique reaches a maximum of 29.18 dB and a minimum of 5.15 dB, whereas the other approaches only manage 0.77–27.04 dB. Additionally, we significantly decreased the average interference level to 5.42 dB compared to competing approaches of 38.84 dB and 34.12 dB. The average sum-rate capacity is also increased to 3.90 by the suggested strategy, outperforming previous approaches. These findings demonstrate how well our cooperative beamforming method reduces interference and improves overall network performance in 5G systems. [ABSTRACT FROM AUTHOR]

ABSTRACT A compact eight‐port MIMO structure containing planar inverted‐F antennas (PIFAs) as radiating elements is designed for 5G cellular communication applications within the sub‐6 GHz band. The proposed antenna consists of four radiating elements that are placed at four corners on the same plane of geometry. The overall dimension of the ground plane is considered to be 59 mm × 120 mm to make it convenient for modern smart mobile handsets. Each radiating element has 2‐feeding plates, which are situated perpendicular to each other in orientation to make the arrangement cross‐polarized, which in turn exploits polarization diversity as well as spatial diversity among the combination of different radiating elements. The patches are structured by embedding rectangular slots in a meandered shape, and the ground plane is configured by introducing rectangular slots and narrow metallic strips. The prototype of the prescribed MIMO PIFA model has been fabricated and experimentally tested. It shows multi‐band operations (3.27–3.37, 4.16–4.35, 4.93–5.06, and 5.47–5.68 GHz) within the sub‐6 GHz spectrum. The isolation among various patches is observed within the range of −35 dB to −42 dB. The peak gain reaches around 8.1 dBi. The designed MIMO PIFA exhibits superior diversity performance by producing ECC ≤ 0.0006, DG ≈ 10 dB, CCL < 0.20 bits/Hz/s, and MEG ≤ −3 dB. Furthermore, the specific absorption rate (SAR) is evaluated according to the standard values of fat, skin, and muscle at 3.3 GHz. The prescribed model maintains acceptable SAR values for 1‐g and 10‐g tissues, which makes it suitable for smartphone applications. [ABSTRACT FROM AUTHOR]

This paper introduces a novel design concept for a compact sub-6 GHz four-port flexible antenna tailored specifically for 5G applications. The antenna utilizes a coplanar waveguide (CPW) architecture featuring a moon-shaped radiating element, implemented on a flexible Felt substrate with a dielectric constant of 1.2. Operating within the 3.4 to 3.8 GHz spectrum, the antenna underwent fabrication and rigorous measurement. Remarkably, the measured results closely matched the simulated outcomes, validating the design's accuracy. Furthermore, various MIMO parameters such as envelop correlation coefficient (ECC), total active reflection coefficient (TARC), channel capacity loss (CCL), diversity gain (DG), and mean effective gain (MEG) were computed, providing comprehensive insights into the antenna's performance metrics. An analysis of the antenna's conformability confirms its suitability for integration across diverse 5G applications. Overall, the findings demonstrate that the proposed antenna exhibits promising characteristics, making it an ideal candidate to meet the evolving demands of 5G communication systems. [ABSTRACT FROM AUTHOR]

This paper proposes a 10 × 10 MIMO multiband broadband planar antenna for tablets or laptops. The designed antennas cover a large number of the popular sub‐6‐GHz application bands, such as 0.617–0.96, 2.1–2.7, 3.5–4.5, and 6.1–7.2 GHz for public safety communications, radio systems, Bluetooth, Wi‐Fi, and satellite communications. The proposed antenna is designed with grounded branches, which can generate a wide bandwidth and cover most of the sub‐6‐GHz application band by coupling between branches of different lengths and antennas. MIMO antennas have been measured to have an envelope correlation coefficient of less than 0.7 and have met the standards set by international organizations for human radiation absorption simulations. The proposed antenna validates the unique 10 × 10 MIMO antenna structure and feasibility. Multiple operable frequency bands are realized, and the radiation effect of the antenna on the human body is analyzed if it complies with international market standards. The proposed antenna design is well suited for multiband and broadband requirements. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A novel compact quad-band multiple-input-multiple-output antenna (MIMO) with high isolation is presented for universal mobile telecommunications systems (UMTS), wireless local area network (WLAN), and 5G: sub-6 GHz wireless communication applications. The proposed antenna is simulated, fabricated on low cost FR4-epoxy substrate of overall size 25 × 50 × 0.8 mm3. The proposed antenna comprises of two orthogonally placed radiators on top of substrate and ISI-shaped defected ground structure (DGS) on the bottom side. High isolation of above 20 dB is achieved with DGS and orthogonal arrangement of antenna elements. The proposed antenna is fabricated and results are tested. The measured results are well matched with simulated results. The antenna resonates at 1.98 GHz (UTMS), 2.75 GHz (WLAN), 3.37 GHz (5G/n78) and 4 GHz (5G/n77) bands with high gain and radiation efficiency. The simulated and measured results demonstrate that the proposed structure is well suitable for wireless communication applications. [ABSTRACT FROM AUTHOR]

This paper introduces a wideband circular patch antenna designed with a frequency selective surface (FSS) for sub-6 GHz applications. The proposed antenna features a monopole circular-shaped patch with a partial ground plane, delivering an omnidirectional radiation pattern in the azimuth plane, resulting in relatively uniform gain in all directions. An FSS metamaterial enhances the antenna's gain and improves the broadside radiation pattern. The design incorporates three inner circular patches connected to the main patch. The FSS utilizes hybrid square/circle loop-based unit cells. The antenna and FSS are simulated using CST software and subsequently fabricated on an FR-4 substrate. The measured results demonstrate an impedance bandwidth of 1.6 GHz with a peak gain of 5.4 dB at 3.5 GHz. The omnidirectional radiation pattern is converted into a directional one by placing a reflector FSS as a bottom substrate layer. The overall structure size is compact, measuring (0.34λ0 × 0.27λ0 × 0.016λ0), where λ0 is the freespace wavelength corresponding to the lowest resonant frequency within the operational bandwidth. This design achieves significant antenna size reduction and is well-suited for future sub-6 GHz applications. [ABSTRACT FROM AUTHOR]

This paper proposes a circularly polarised co-planar waveguide (CPW) based on a two-component multiple-input-multiple-output (MIMO) antenna for 5 G communications in the band of sub-6 GHz. The practical dimension of the proposed antenna is 49.35 mm × 98.7 mm × 1.6 mm. Three complementary-split-ring-resonators (CSRR) are applied to resonate at 3.3 GHz and 3.84 GHz. The optimised proposed antenna can be used for 5 G LTE-band (n74-n78) worldwide, 2 G, 3 G, 4 G, WiFi and WiMAX applications (1 GHz–4.4 GHz). The radiation efficiency is significantly more than 60% and for the specified 5 G band (sub-6 GHz), the measured efficiency is 80% to 85%. The proposed antenna has achieved high isolation (more than 30 dB) and excellent diversity performance like Envelope Correlation Coefficient (ECC), Diversity Gain (DG), Total Active Reflection Coefficient (TARC) and Channel Capacity Loss (CCL). Simulated results are also verified with experimental results. [ABSTRACT FROM AUTHOR]

Choosing polymers as antenna substrates has become a significant challenge, as it involves addressing the escalating demands of emerging 5G applications for bandwidth and data transfer, while simultaneously prioritizing environmental adaptability. Furthermore, various applications such as IoT and smart wearables utilize specific frequency bands, such as sub-6 GHz, millimeter waves (MMwaves), and terahertz, which are characterized by unfavorable conditions of propagation. The current in-depth study focuses on the exploration of two specific polymers, Polymethyl methacrylate (PMMA) and Polydimethylsiloxane (PDMS), as potential substrates for designing flexible microstrip antenna operating at 5.8 Ghz. The proposed antenna showcases a compact design, measuring 25.6 × 45.6 × 2.2 mm3 for PMMA and 20.2 × 40.2 × 2.2 mm3 for PDMS. Notably, with a consistent substrate thickness of 2.2 mm, the PMMA polymer outperforms PDMS, achieving a higher gain of 4.4dBi compared to PDMS's gain of 3.75dBi. Furthermore, both substrates exhibit improved performance under bending conditions and excellent impedance matching, it is worth that in both cases, the return loss remains under 22 dB. This comprehensive analysis firmly establishes the viability of PMMA and PDMS in delivering efficient flexible microstrip antenna performance, thereby contributing significantly to the advancement of IoT devices technology and design within the Sub-6 GHz frequency band. [ABSTRACT FROM AUTHOR]

The increasing need for swift, low-latency, and reliable wireless transmission in the age of 5G has led to rapid advancements in 5G technology. MIMO systems, originally implemented in 4G applications, remain an integral part of 5G networks. The sub-6-GHz frequency band holds promise for 5G applications, such as improved link and reduced transmission losses. This comprehensive review explores advancements in patch antenna (PA) structure for sub-6 GHz 5G smartphone utilization, addressing the challenges posed by space constraints in mobile devices and the need for efficient integration of antennas. The paper discusses the significance of MIMO antennas in modern cellular communication, particularly in the context of 5G technology, which utilizes sub-6 GHz. Reconfigurable antennas (RAs) and Microstrip Patch Antennas (MPAs) are introduced as solutions, highlighting their compact, cost-effective, and flexible nature. The review delves into critical factors such as geometry, substrate selection, and feed design in optimizing patch antenna performance. It also covers the importance of addressing both sub-6 GHz and mm-wave bands within a single antenna system. [ABSTRACT FROM AUTHOR]

A tri-band shared-aperture antenna for Sub-6 GHz/millimeter-wave (mmWave) applications with a scanning beam is proposed. Using structural multiplexing, the dual-band Sub-6 GHz mesh patch antenna and the millimeter-wave (mmWave) Fabry-Perot cavity antenna (FPCA) share the same radiating aperture. The metal mesh patch acts as both the radiator of the dual-band mesh patch antenna and the partial reflective surface (PRS) of the FPCA. The mechanism of the FPCA is analyzed using the ray tracing method. With the designed single-layer PRS, the proposed antenna features a scanning beam in the mmWave band without the need for tuning elements and feeding networks. An aperture-coupled patch antenna is designed as the feed source for the FPCA. Additionally, by optimally shaping the metal mesh, the patch antenna generates dual-band resonances. The antenna prototype is fabricated and measured. Measured results show that the impedance bandwidth of the antenna is 2.07% (2.39 − 2.44 GHz), 24.79% (3.18 − 4.08 GHz), and 28.42% (24.90 − 33.15 GHz), respectively. The tri-band peak gains are 8.18 dBi, 8.39 dBi, and 17.41 dBi, respectively. The beam scans from 2° to 39° in the frequency range of 25 − 33 GHz. [ABSTRACT FROM AUTHOR]

A slotted theta-shaped patch antenna (TSPA) featuring a distinctive defected ground structure (DGS) is designed and presented for 5G (fifth-generation) Sub-6 GHz applications. The prototype is designed and fabricated using an affordable, widely available FR-4 (εr=4.3,tanδ=0.025) substrate and 1oz copper printed on both size. The proposed antenna's dimensions have been optimized to 35 × 34 × 1.6 mm3 (0.39λ×0.37λ×0.02λ). A conventional DGS for the TSPA is also modeled and fabricated to facilitate comparison. A thorough comparison of the two designs is made to show that the proposed antenna performs better than conventional DGS single-band patch antenna. The suggested antenna is suitable for the n77 (3.3–4.2 GHz) and n79 (4.4–5 GHz) bands, as it operates across two separate frequency bands at 4.19 GHz and 4.91 GHz, respectively. The proposed antenna demonstrates a dual-band performance, offering a broader bandwidth of 130 MHz at 4.19 GHz and 890 MHz at 4.91 GHz, along with an improved reflection coefficient of -30 dB at both frequencies. This contrasts with the conventional DGS of the single-band TSPA, which has a reflection coefficient of -26 dB at 4.85 GHz. By incorporating a modified DGS-based partial ground, the proposed antenna is enhanced from a single-band to a dual-band design with improved bandwidth. Parametric studies examine the impact of different substrate materials and variations in DGS line width and length on antenna performance. The findings of this research are crucial for deploying wider bandwidth patch antennas in sub-6 GHz 5G wireless communications, demonstrating the proposed design's potential to significantly boost performance.

Abstract This paper presents a novel quad-element array with multiple inputs and multiple outputs (MIMO) designed for 5th generation sub-6 GHz applications. The MIMO system achieves a wide impedance bandwidth, high gain, and high isolation among its components, representing significant advancements in sub-6 GHz antenna applications. The single element, an elliptical resonator with a circular slot, is fed by a 50 Ω microstrip feedline, achieves a broad characteristic bandwidth from 3.7 to 5.7 GHz with a resonant frequency of 4.33 GHz and a gain of 1.81 dBi. Characteristic Mode Analysis (CMA) was employed to elucidate the evolution phases of this design. The quad-element MIMO antenna array maintains a compact size and broadband characteristics by arranging mirrored elements on the same ground plane. Implemented on a cost-effective FR-4 substrate measuring 44 × 44 × 1.6 mm3, the recommended MIMO antenna array, enhanced with a partial ground plane and due to the introduction of a vertical strip, a high isolation of − 38.53 dB is achieved between MIMO components along with a realized gain of 3.01 dBi and a radiation efficiency of 71% in the 5G sub-6 GHz band. Noteworthy properties include high isolation, diversity gain (DG), and envelope correlation coefficient (ECC), verifying the appropriateness of the suggested MIMO scheme for 5G transmission and reception in sub-6 GHz applications.

In this paper, the path loss performance of an eight-port Multiple-In-Multiple-Out (MIMO) antenna consisting of four circular slots radiator-based antenna elements is investigated in 3.5–3.75 GHz range for utilisation as an RFID tag and reader antenna. First, the S-parameters between the ports of two proposed MIMO antennas are measured in four channels of spatial diversity; one direct line-of-sight (LOS) and three indirect LOS in an anechoic chamber, each for the horizontal and vertical polarisation schemes at two distances, 5 and 25 cm, and the path losses between the ports of MIMO antennas are evaluated. Then, the path losses between the same MIMO antennas are obtained in a laboratory environment, which are higher by about 5–10 dB than those in the anechoic chamber and so, these losses are more dependent on the antenna position and nearby objects. The tag power sensitivity and the tag (read) range for the presented MIMO antenna are found to be more power level dependent than frequency dependent. The reported results confirm the performance of proposed MIMO antennas for RFID applications in addition to 5 G communications. [ABSTRACT FROM AUTHOR]

The impact of electromagnetic radiation from communication on the male reproductive system has emerged as a significant concern in public health. A notable distinction of the 5G sub-6 GHz band, compared to traditional 2G, 3G, and 4G frequency bands, is the inclusion of higher frequency bands. This has raised public concerns regarding the potential effects of these higher frequencies on organisms, particularly their reproductive systems. While it is imperative to investigate the biological effects and potential risks associated with these new frequency bands in laboratory settings, comparing and evaluating differences between various frequency bands remain challenging due to the absence of standardized parameters such as exposure conditions and duration. In contrast, dose assessment offers a simpler and more reliable approach. The dose assessment method was employed in this study to investigate the risks associated with sub-6 GHz electromagnetic radiation from 5G base stations on the male reproductive system. A classical human body model (Duke) was utilized, and an electromagnetic simulation environment was established based on the actual polarization direction of the exposed base stations and various body postures. This research explored the effects of field direction, posture, public population, and frequency on the specific absorption rate of the reproductive system. While maintaining the same level of exposure, a higher frequency results in a reduced dosage on reproductive system. Further analysis reveals that, considering the public exposure threshold, the employment of higher frequency bands in 5G sub-6 GHz does not present a greater dosage on reproductive system compared to lower frequency bands. Consequently, with regard to dosage, there is no need for excessive concern among the general public regarding the impact of electromagnetic radiation emitted by 5G base stations operating below 6 GHz on male reproductive health. [ABSTRACT FROM AUTHOR]

This paper presents a compact, high-isolation MIMO antenna with physical dimensions of 68 × 68 × 0.8 mm, designed for use in 5G applications. The antenna’s bandwidth ranges from 3.25 GHz to 4.34 GHz and it offers a gain of 4.3 dBi, making it suitable for applications relying on 5G technology. Several improvements have been introduced to improve its overall efficiency, such as adjustments to the ground plane and integrating apertures in the radiating patch. The alterations referred to above were optimized using the sweep parameter method to ensure that their best configurations are achieved. Furthermore, much attention has been paid to enhance isolation by ensuring all terminals are positioned precisely at 90° angles. The CST Studio Suite was utilized to design and thoroughly simulate the proposed MIMO antenna. [ABSTRACT FROM AUTHOR]

The wireless technology is witnessing two interconnected trends that have significant implications. Firstly, there is an ever-increasing demand for high-speed data transfer and extensive bandwidth, driven by the rapid expansion of modern smart applications. This relentless demand has forced new wireless networks, such as 5G and 6G, to explore new frequency bands, such as Sub-6 GHz, to accommodate the surging data requirements. Secondly, the remarkable growth in applications with stringent environmental conditions, extending beyond healthcare and biomedical research, to industries such as industrial automation, environmental monitoring, agriculture, transportation, and smart cities, demand wireless devices and communication technologies that can function optimally in delicate and sensitive environments, without compromising on performance. Hence, the simultaneous growth of these trends highlights the critical significance of incorporating eco-friendly and environmentally adaptable polymers in the design of new antennas. This approach becomes essential to ensure the development of resilient and flexible wireless devices that can function optimally in diverse and challenging environments. The present work delves into the performance analysis of rectangular and circular microstrip antennas design for sub-6 GHz band. The specific areas of interest include investigating how the thickness of the PLA (Polylactic Acid) substrate influences antenna design and employing Carbon Nanotubes (CNTs) as the conductive material for both the antenna feed and the ground plane. The combined use of PLA and CNTs resulted in compact circular and rectangular antennas, with dimensions of 25.8 × 45.8 mm2 and 26.4 × 42.1 mm2, respectively. Notably, both antennas exhibited an impressive realized gain exceeding 4.9 dBi and an efficiency surpassing 73% at 5.8 GHz, demonstrating robust performance under various substrate thicknesses, including flat and bending scenarios. These outstanding outcomes position the proposed microstrip antennas as highly suitable candidates for a broad spectrum of emerging applications within the sub-6 GHz band. [ABSTRACT FROM AUTHOR]

As the number of wirelessly connected devices continues to grow, dealing with the huge volume of data traffic has become a major challenge. This has led to a greater emphasis on sub-6 GHz applications in 5G, as faster speeds and more extensive services are increasingly necessary to support a wide range of emerging applications. These applications require wireless devices with compact dimensions and highly flexible mechanical properties that can adapt to their environmental needs. To achieve this, flexible polymers offer numerous advantages, including lightweight, low cost, easy processability, and the ability to conform to complex and irregular surfaces, making them ideal for use in wearable devices and other flexible electronics applications. This work provides a thorough analysis of a dual-band microstrip patch antenna, measuring 18 × 27 × 0.3 mm3 for polyimide polymer (PI) and 19.5 × 29.5 × 0.3 mm3 for liquid crystal polymer (LCP). The obtained results obviously depict that the antenna performs better in terms of reflection coefficient (S11) and the realized gain (dBi) at the (2.34–2.56 GHz) and (4.45–5.78 GHz) frequency bands when the substrate is approximately 0.3 mm thick. The antenna also maintains its performance during bending tests. Furthermore, the LCP polymer provides a higher gain of about 3.51 dBi as compared to the polyimide polymer (PI). The results suggest that the proposed antenna is suitable for a wide range of wireless 5G communication devices operating in the sub-6 GHz band. [ABSTRACT FROM AUTHOR]

This work puts forward a sub-6 GHz 5G microstrip patch antenna at 2.22 GHz. The simplicity and symmetry inherent in its design gives it an exceedingly high fabrication tolerance rate, and these characteristics coupled with its actual functional capabilities, makes it a much more potentially preferable device, in comparison to similar works in its specific category. The specific numerical values of the variables/parameters of this particular sub-6 GHz 5G microstrip patch antenna, which has a high fabrication tolerance, are as such: s11 = -9.77 dB, frequency = 2.22 GHz, εθ = -28.36 dB, εΦ = 5.27 dB. The inspiration for this work came from slot-based patch antenna for sub-6 GHz 5G applications discussed in the literature, which posed three slits and no slots, whereas this work has produced a geometry, with five slits and three slots, along with many other unique characteristics. The results showed that this small antenna shows significant reach and significantly lower costs due to the simple manufacturing process compared to similar devices. [ABSTRACT FROM AUTHOR]

This manuscript proposed a compact four-port multiple input multiple output (MIMO) antenna based on four split-ring resonators (SRR) at the top and a defected ground structure (DGS) at the bottom of the substrate for 5G communication. SRRs are used to resonate at 4 GHz frequency in mid-5G band. A slot of " + " symbol is cut at the bottom (DGS) to enlarge the bandwidth. The proposed antenna also achieved a high-5G frequency band (26.8–29.8 GHz) (n257/n258 band) by four square-shaped ring slots at the ground plane. It further enhances the bandwidth in mid-5G band (2.9–6 GHz) (n74/n75/n76/n77/n78 band) and helps to achieve a high degree of isolation between each radiating element (over 40 dB) at both the 5G bands. The size of the proposed MIMO antenna is 60 mm × 60 mm × 1.6 mm. It achieves a maximum gain of 4.59 dB, 4.32 dB at the mid-5G and high-5G band, respectively. The maximum radiation efficiencies achieved are 89%, 81% at the mid-5G and high-5G band, respectively. The diversity functionality of the antenna is also outstanding as the value of ECC is 0.01–0.42, DG is 9.6–10 dB, and TARC is less than − 10 dB measured in both the bands. The entire performance of the proposed antenna is practically verified, discussed and presented. [ABSTRACT FROM AUTHOR]

This paper presents a symmetric dual-band multiple-input multiple-output (MIMO) antenna system tailored for fifth-generation (5G) mobile terminals. Operating within the 5G frequency bands N77/N78 (3.4–3.6 GHz) and N79 (4.8–5.0 GHz), the proposed MIMO system achieves high isolation between adjacent antenna elements through slotting and self-decoupling technologies. Antenna elements are strategically positioned on two frames perpendicular to the smartphone's main board. Each antenna element integrates a rectangular microstrip radiator on the inner frame surface, accompanied by a grounded rectangular ring on the outer frame surface. The feed line, situated atop the main board, connects to an external SMA connector located at the main board's bottom. Measurement results reveal isolations exceeding 20 dB for the lower band and 24 dB for the higher band. The fabricated and tested MIMO antenna system demonstrates excellent agreement between simulation and measurement outcomes. [ABSTRACT FROM AUTHOR]

This paper presents a compact, high-isolation MIMO antenna with physical dimensions of 68 × 68 × 0.8 mm, designed for use in 5G applications. The antenna's bandwidth ranges from 3.25 GHz to 4.34 GHz and it offers a gain of 4.3 dBi, making it suitable for applications relying on 5G technology. Several improvements have been introduced to improve its overall efficiency, such as adjustments to the ground plane and integrating apertures in the radiating patch. The alterations referred to above were optimized using the sweep parameter method to ensure that their best configurations are achieved. Furthermore, much attention has been paid to enhance isolation by ensuring all terminals are positioned precisely at 90° angles. The CST Studio Suite was utilized to design and thoroughly simulate the proposed MIMO antenna.

Abstract Background The rapid expansion of modern smart applications, demanding faster data transfer and extensive bandwidth, has prompted the development of new-generation networks like 5G and 6G. These networks encompass additional frequency bands such as sub-6 GHz, millimeter waves, and terahertz bands to meet the growing bandwidth requirements. However, despite the substantial bandwidth available in these bands, several challenges must be addressed to overcome unfavorable propagation characteristics. Moreover, numerous applications necessitate wireless devices with antennas that exhibit high flexibility and exceptional radiation responses, particularly when subjected to bending effects. This requirement highlights the importance of polymers-based antennas that can adapt to changing conditions while maintaining optimal performance. The present comprehensive study delves into the performance evaluation of rectangular and circular microstrip antennas utilizing PMMA (polymethyl methacrylate) polymer substrate with varying thicknesses. Results Notably, CNTs (Carbon Nanotubes) are employed as an alternative to traditional copper for the conductive part and ground plane. Both PMMA-based antennas, integrated with CNTs, exhibit a compact footprint of 27.8 × 47.8 × 1.5 mm3 for the circular antenna and 22.8 × 39.5 × 1.5 mm3 for the rectangular antenna. Impressively, the realized gain of both antennas surpasses 5 dBi, demonstrating robust performance in both flat and bending scenarios across different substrate thicknesses. Conclusions The rectangular antenna achieves a bandwidth of approximately 200 MHz, while the circular microstrip antenna showcase annotable bandwidth of 500 MHz. These exceptional outcomes position the two microstrip antennas as highly suitable for a diverse range of emerging applications within the sub-6 GHz band (the frequency range below 6 GHz in the radio spectrum). Thus, the combination of PMMA substrate, CNTs and the compact form factor of the antennas presents a compelling solution for meeting the demands of modern applications requiring efficient wireless communication with enhanced performance and bandwidth.

This study introduces a cost-effective monopole antenna array and its MIMO configuration. The single element consists of a rectangular patch monopole featuring five circular slots at the center, accompanied by two thin slots at the top, offering a wide bandwidth (2–7.62 GHz) and a peak gain of 3.8 dBi. For gain improvement, a 2 × 1 antenna array is demonstrated. This antenna array exhibits dual-band behavior; spans from 2 to 3.71 GHz and from 5.9 to 7.54 GHz; covers the 2.5 GHz band (2.3–2.7 GHz), a significant portion of the n78 band (3.3–3.71 GHz), and the n96 band (5.925–7.125 GHz); and is assigned to WiMAX, sub-6 GHz, and sub-7 GHz applications, respectively. The antenna array achieves a peak gain of 6.47 dBi. Lastly, a two-element MIMO configuration derived from the 2 × 1 array is designed. Implementing a defected ground structure (DGS) on the ground plane plays a crucial role in enhancing the isolation from 7 dB to 20 dB. The presented MIMO antenna covers the desired frequency bands of 2.5 GHz, n78, and n96 with a peak gain of 7.5 dBi and high radiation efficiency (<99%), which qualifies it for WiMAX, sub-6 GHz, and sub-7 GHz applications. [ABSTRACT FROM AUTHOR]

This paper deals with the design, simulation, and practical modeling of metamaterial-based multiband conformal bandpass filter (BPF) for various wireless communication applications with improved quality factors. The novel metamaterial in the form of a split ring resonator is loaded on the ground plane face of the proposed BPF. The overall dimension of the designed BPF is only 2 8 × 2 8 mm 2 . The proposed BPF is tuned initially for quality factor enhancement based on the thickness of the substrate, physical parameters of the f transmission line, ground plane, externally loaded elements, and the gap in the metamaterial loading. The suggested filter operates at triple band covering the frequency bands from 1.4 to 2.2, 3.6 to 3.9, and 4.8 to 5.9 GHz, which are suitable for sub-6 GHz 5G and other wireless applications. The insertion loss is observed as 1 dB, which is suitable for the proposed BPF. The conformal behavior of the filter is judged through bending deformation analysis at various bending positions like (15 ∘ , 30 ∘ , 45 ∘ , 60 ∘ , and 90 ∘ ). The proposed BPF retains triple pass band characteristics at various bending deformations, which makes it suitable to be used in curved structures or flexible circuitry. The theory of equivalent circuits and quality factor (Q) of the designed BPF is discussed in this paper. The results are analyzed experimentally through ANRITSU-MS2037C combinational analyzer. The proposed BPF is suitable for sub-6 GHz 5G, WLAN, and Wi-Max applications. [ABSTRACT FROM AUTHOR]

This paper presents an 8-port MIMO antenna array for use with 5G handsets. The proposed MIMO antenna array comprises eight U-shaped, coupled-fed slot antenna components placed symmetrically on a 0.8 mm thick FR4 substrate. Each antenna has 200 MHz bandwidth and covers 3.4-3.6 GHz. The operational frequency range includes LTE band 48 for 5G cellular applications. Using spatial and polarisation diversity, antenna components are isolated by over 15 dB. The prototype antenna is fabricated and measured, and the experimental results agree with the simulated results. The estimated Envelope Correlation Coefficient (ECC), less than 0.035 based on radiation characteristics, shows that the suggested MIMO antenna array performs well in diversity. These characteristics indicate that the proposed MIMO antenna is a viable solution for 5G smartphone applications. [ABSTRACT FROM AUTHOR]

Multiband MIMO antenna system is very important in 5G mobile communication to meet the requirements of increasing data rate. However integrating multiple antennas in the limited space causes mutual coupling. The antenna configuration gets more intricate, if additional circuitry is installed to obtain greater isolation and hence, the occupied area on the board grows significantly, making the overall antenna design bulky. Hence, to provide dual band coverage, decent isolation and compact design, a compact MIMO antenna system is presented in this paper. The proposed system includes a T-shaped resonating structure that is employed on the side-frames to form a MIMO system with eight antennas. The T-shaped strip is designed to resonate at two frequencies and thereby covering two 5G bands (LTE 42/LTE 46). The proposed dual band MIMO system is fairly compact as the individual antennas are mounted on the 150 × 3.6 mm 2 side-frames of the smartphone. The isolation between antenna elements is 14 dB. This is accomplished without the need of a decoupling structure or a complex tuning process. The ergodic channel capacity realized by the suggested MIMO system in the operational bands is more than 41 b/s/Hz and ECC is less than 0.075. The impacts of the presence of plastic frame, display panel and phantom hand on the performance of proposed design are discussed. The proposed design provides compactness, dual band coverage and high isolation. [ABSTRACT FROM AUTHOR]

When it comes to the radio frequency (RF) frontend, power amplifier (PA) is one of the most important functional blocks for dependable wireless transmission. In order to provide the necessary output power, PAs boost and amplify the incoming signal, to ensure that the transmitter's signal reaches the receiver at the necessary distance. The PAs have not yet managed to find place within the transceiver circuit due to its bulky nature. Although rigorous efforts have been made to improve the linearity and efficiency of the PAs, it has come at the cost of increase in chip area. This paper focusses on design of an RFPA in an 18nm FinFET advanced node technology that is adaptable to the Sub-6 GHz frequency band of 5G communication standard so as to provide maximum output power at the operating frequency of 3.5GHz. The single stage PA, thus designed and simulated on Cadence Virtuoso provides a gain of 27.71 dB at a supply voltage of 1V. The bandwidth is 208 MHz, power gain is 25dB and the output power is 6.335 dBm. The simple design with a single transistor paves way for a considerable decrease in the chip area, thus making it possible to be placed within the transceiver chip. [ABSTRACT FROM AUTHOR]

In this paper, a compact two-element reconfigurable multiple-input multiple-output (MIMO) antenna for 5G new radio sub-6 GHz is presented and discussed. The proposed MIMO antenna has four frequency operating modes: a wideband operating mode (2.41–6 GHz), a wideband operating mode with a notching band at 3.5 GHz (3.2–3.66 GHz), a low-pass filter mode that filters the higher frequencies with a wide operating band from 2.41 GHz to 4.7 GHz, and a dual-band mode with two operating narrow bands (2.41–3.16 GHz and 3.64–4.7 GHz). To improve the isolation over the entire operating band, a strip line connecting the two ground planes of the two antenna elements has been used. To validate the proposed approach, different prototypes have been fabricated and measured. The simulation results are in good agreement with the measurement results. The proposed antenna has good MIMO diversity performance with a maximum gain of 4.64 dBi. The minimum isolation is 18 dB for the four operating modes, while a measured envelope correlation coefficient of less than 0.008 is achieved. The diversity gain is near 10 dB for various operating modes. The antenna is suitable for cognitive radio and 5G sub-6 GHz applications. [ABSTRACT FROM AUTHOR]

This paper presents, a modified rhombus-shaped antenna designed and analyzed using characteristic mode analysis (CMA) for a sub-6 GHz range of 5G. The proposed antenna is extended to design a 2 × 1 MIMO antenna having a wide bandwidth of 2600 MHz (3.2–5.8 GHz). The high level of mutual coupling (|S21|= − 12.31 dB at 4.75 GHz) exhibited by MIMO antenna is alleviated with the help of modified hexagonal-shaped mu-negative (MNG) metamaterial unit cells. Using CMA, MNG unit cells are placed (onto MIMO antenna) such that orthogonal modes are generated within MIMO antenna elements resulting in a high isolation level (S21 < − 25 dB) for the entire operating range of bandwidth (with peak value of − 34.4 dB at 4.75 GHz). This also aids in the miniaturization of MIMO antenna by enabling the placement of antenna elements at a minimized edge-to-edge gap of 0.13λ (where, λ is the resonating frequency). The proposed MIMO antenna with MNG unit cells (called MNG-MIMO antenna) exhibits good envelope correlation coefficient with (ECC < 0.001) and diversity gain (DG = 9.9 dB), along with a high radiation efficiency of 82% while retaining a wide-bandwidth (2600 MHz). Also, the proposed MNG-MIMO antenna exhibits circular polarization (Axial ratio < 3 dB) in the frequency range of 4.56–4.89 GHz. An eight-element MNG-MIMO antenna (called eight-element MNG-MIMO) with a ground plane of 170 × 80 mm2 is analyzed to highlight the practicality of the proposed MNG-MIMO antenna. The obtained simulated response of eight-element MNG-MIMO indicates no change in efficiency and ECC levels however a minor variation in isolation is observed. Thus with a compact volume of 990mm3, the proposed design is fit for various 5G and IoT applications. [ABSTRACT FROM AUTHOR]

A miniaturized, multi-band, four-port wearable Multiple Input Multiple Output (MIMO) antenna is proposed, which contains a leaky wave textile antenna (LWTA) on denim (εr = 1.6, tanδ = 0.006) as substrate and Shieldit Super Fabric as conductor textile. The concept in this work involves incorporating the metal and plastic zipper into the garment to function as an antenna worn on the body. Simulations and measurements have been conducted to explore this idea. The LWTA has dimensions of 40 × 30 × 1 mm³. Every two ports are separated by a zipper with two different kinds of materials: Acetal Polymer Plastic (APP) and 90 % brass to improve the isolation, gain, and Impedance bandwidth. The antenna operates in the frequency ranges covering the L, C, S, and X bands. Additionally, diversity performance is evaluated using the Envelope Correlation Coefficient (ECC) and diversity gain (DG). Simulation and measurement findings agree well, with a maximum gain of 12.15 dBi, low Specific Absorption Rate (SAR) based on the standards, DG greater than 9.65 dB, circular polarization (CP), and strong isolation (

New multiband antenna array structure with high gain is proposed for 5G communication handheld systems (700MHz/3.5 GHz and 28/38 GHz). The designed structure is proposed using a combination of sub-6GHz and mm-Wave antenna arrays. The antenna is based on S-shaped strip etched on the top side to operate at 700 MHz. On the other hand, the 3.5GHz band is generated by coupling a meander line to an inverted-C strip on the bottom side. Finally, the mm-Wave antenna array is based on four quadrupole elements with a 1:4 microstrip power divider. This configuration ensures that all four quadrupole antennas receive in-phase feeding power. Obtained results confirm that the designed antenna array achieves gains of 4.6 dBi, 10.5 dBi, at sub-6 GHz and mm-Wave band, respectively. Owing to its simplicity and compactness, the proposed handset antenna is a good candidate for 5G multiband applications.

In this paper, a microstrip bandpass filter for dual-band sub-6 GHz 5G mobile communications is designed. The two first resonance frequencies of the stepped-impedance resonator are used as the operating frequencies of the two passbands. Furthermore, the stepped-impedance resonator is folded to form open-loop stepped-impedance resonator for compactness. This form of the resonator generates a second transmission zero in the upper stopband which improve the out of-band rejection. A 50 Ω tapped-line input/output is used to feed the filter. The proposed structure is designed, analyzed and manufactured and their measured results are found to be in good agreement with the simulation results. From the measured results, it is found that the proposed filter achieved return loss of 21 dB and 28.3 dB, insertion loss of 0.4 dB and 1.7 dB and bandwidth of 12.5 % and 10.81% at 3.61 GHz and 5.55 GHz, respectively. In addition, the proposed filter has a compact size which make it suitable for sub-6 GHz 5G mobile communications. [JJCIT 2023; 9(4.000): 287-293]

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.

This article presents the design of a low-loss microstrip dual-band bandpass filter with improved inter-band isolation and selectivity for 5G sub-6 GHz mobile communications. The proposed filter utilizes the two first resonance mode frequencies provided by the stepped-impedance resonator to generate its two passbands at 3.6 GHz and 3.5 GHz, and spur-lines located before the input/output ports to improve the isolation and selectivity between passbands. The filter is designed using an RT/Duroid 5870 substrate with a relative permittivity of 2.33 and a thickness of 0.79 mm, manufactured and tested to validate the proposed design. The experimental results show that the filter operates at 3.61 GHz and 5.51 GHz with a 3-dB fractional bandwidth of 12.74% and 16.7%, respectively. Insertion losses at the two passbands center frequencies are 0.6 dB and 0.9 dB. In addition, the proposed filter has the advantage of covering the licensed and unlicensed 5G bands and provides a simple structure without using vias or DGS structures.

The article investigates a compact low profile guitar shaped antenna loaded with co-directional complementary split ring resonator(CO-CSRR) based on negative permittivity metamaterial for sub-6 GHz 5G applications.The inclusion of metamaterial on the radiator produces two popular frequency bands n78 5G NR (3.13–4.01) GHz and n79 5G NR (4.98–6.19) GHz with gain of 5.75 dBi and 6.3 dBi respectively. The design is able to achieve high impedance bandwidth of 700 MHz and 1040 MHz at 3.6 GHz and 5.2 GHz with low return loss (S11

This paper proposes four-ring slot resonator-based MIMO antennas of 75 x 150 mm2 without and with CSRR structures in the sub-6-GHz range. These orthogonal-fed antennas have shown diverse characteristics with dual polarization. L-shaped parasitic structures have increased the isolation (i.e., >40 dB) in the single-element antenna over the band of 3.4 GHz?3.8 GHz. A set of three CSRR structures in the MIMO antenna reduced the coupling between antenna ports placed in an inline arrangement and enhanced the isolation from 12 dB to 20 dB and the diversity characteristics. The Sparameters of both MIMO antennas are measured and used to evaluate MIMO parameters like ECC, TARC, MEG, and channel capacity loss. The simulation results show the variations in the gain and directivity on exciting linear and dual polarizations. The diversity performance of the reported MIMO antennas is suitable for 5G applications.

A compact wearable four-element dual-band antenna with good isolation is presented here. The antenna constitutes of a circular monopole with slits and slots incorporated into it to generate dual-band function, and a unique defected ground structure (DGS) with vertical stubs to neutralize coupling current and enhance isolation. The proposed antenna has a dimension of 62 × 52 × 0.25 mm3, bandwidth of 3.8–4.43 GHz (15.31%) and 5.25–6.3 GHz (18.18%), and 5.2 dBi peak gain. The specific absorption rate (SAR) analysis in W/kg for 1/10 g tissue exhibits values of 0.877/0.356 at 4.1 GHz and 0.309/0.105 at 5.3 GHz respectively. The antenna radiation characteristics are analysed using characteristic mode analysis. Furthermore, the diversity parameters are investigated, and the antenna exhibits relatively good results with envelope correlation coefficient (ECC) 9.99 dB, total active reflection coefficient (TARC)

Summary: This article communicates a novel compact four‐element orthogonal cavity‐backed antenna for 5G applications with enhanced isolation. The proposed dumbbell‐shaped substrate integrated waveguide–multiple input/multiple output (SIW‐MIMO) antenna resonate at 5.25 GHz (sub‐6 GHz) based on vias and resonate at 27 GHz (mm‐wave) with copper filling vias using FR‐4 substrate. Both prototypes are separately designed, fabricated, and tested using same dimension (40 mm × 40 mm × 1.6 mm) as well as same radiating structure. Moreover, SIW MIMO antenna design performances are compared between FR‐4 and Rogers RT/Duroid substrate. Deployment of SIW technique in MIMO antenna minimizes the antenna footprint and mutual coupling without involving any decoupling structure. The antenna simulation characteristics of both operating bands are compared and validated with the measurement results. Furthermore, the MIMO diversity parameters are examined. [ABSTRACT FROM AUTHOR]

This article presents a 6×6 MIMO array optimized for sub-6 GHz mobile and wireless applications. Utilizing a partial ground plane (PGP), the array incorporates a single-element half-circle-slotted monopole antenna to achieve a wideband response. The compact design, measuring 75 × 150 mm² and only 0.508 mm thick, is engineered to fit 6.6-inch display smartphones. Operating between 2.82 and 5.95 GHz, the array offers a -10 dB bandwidth and a VSWR of less than 2. It also delivers port-to-port isolation less than -20 dB and a peak realized gain of 5.3 dBi, with an antenna efficiency of 71%. Comprehensive far-field radiation patterns are observed across all 6 ports. The array maintains an envelope correlation coefficient (ECC) under 0.004 and a diversity gain (DG) above 9.98, demonstrating robust performance. Specific absorption rate (SAR) results at 3.5 GHz confirms compliance with MIMO standards, with values as low as 0.13 W/kg. This high-performance MIMO array is a strong contender for sub-6 GHz 5G applications. [ABSTRACT FROM AUTHOR]

In this paper, a microstrip bandpass filter for dual-band sub-6 GHz 5G mobile communications is designed. The two first resonance frequencies of the stepped-impedance resonator are used as the operating frequencies of the two passbands. Furthermore, the stepped-impedance resonator is folded to form an open-loop stepped-impedance resonator for compactness. This form of the resonator generates a second transmission zero in the upper stopband, which improves the out-of-band rejection. A 50 Ω tapped-line input/output is used to feed the filter. The proposed structure is designed, analyzed and manufactured and the measured results are found to be in good agreement with the simulation results. From the measured results, it is found that the proposed filter achieved a return loss of 21.5 dB and 28.3 dB, an insertion loss of 0.4 dB and 1.7 dB and a bandwidth of 12.5% and 10.81% at 3.61 GHz and 5.55 GHz, respectively. In addition, the proposed filter has a compact size, which makes it suitable for sub-6 GHz 5G mobile communications. [ABSTRACT FROM AUTHOR]

This paper proposes an eight-element dual-band multiple-input multiple-output (MIMO) antenna that operates in the fifth generation (5G), n78 (3400–3600 MHz), and WLAN (5275–5850 MHz) bands to accommodate the usage scenarios of 5G mobile phones. The eight antenna elements are printed on two long frames, which significantly reduce the usage of the internal space of the mobile phone. Each antenna element is printed on both surfaces of one frame, which consists of a radiator on the internal surface and a defected ground plane on the outer surface. The radiator is a rectangular ring fed by a 50 Ω microstrip line which is printed on the top surface of the system board. A parasitic unit is printed on the outer surface of each frame, which is composed of an inverted H-shaped and four L-shaped patches. Each parasitic unit is connected to the internal surface of the frames through a via, and then it is connected to a 1.5 mm wide microstrip line on the top surface of the system board, which is connected to the ground plane on the bottom surface of the system board by a via. Four L-shaped slots, four rectangular slots, and four U-shaped slots are etched onto the system board, which provides good isolation between the antenna elements. Two merged rectangular rings are printed on the center of each frame, which improves the isolation further. The return loss is better than 6 dB, and the isolation between the units is better than 15 dB in the required working frequency bands. In addition, the use of a defected ground structure not only makes the antenna element obtain better isolation but also improves the overall working efficiency. The measurement results show that the proposed MIMO antenna structure can be an ideal solution for 5G and WLAN applications. [ABSTRACT FROM AUTHOR]

This work proposes a novel dielectric resonator antenna design for 5G-based IoT applications that operates in the sub-6 GHz frequency range. The DR antenna is built on a 1.6-mm-thick FR-4 substrate with dimensions of 30*50 mm2. The proposed dielectric resonator antenna is made of alumina and is excited using a microstrip feedline of 50 Ω. Because of the hybrid arrangement of cylindrical and rectangular dielectric resonator elements on the FR4 substrate, this proposed structure has improved the radiation mechanism. The antenna design process begins with creating the antenna in the Ansys HFSS EM simulator, which is then optimized using machine learning based on the antenna geometry's target factors. A data set of 2625 sample data values is generated in HFSS and fed to various machine learning algorithms for further optimization based on data trends. Post-optimization, the antenna design is fabricated and tested. The proposed antenna offers a wide bandwidth of 1.1 GHz between 3.5 and 4.6 GHz and resonates at 3.9 GHz making it suitable for 5G sub-6 GHz IoT applications. [ABSTRACT FROM AUTHOR]

This paper presents a symmetric dual-band multiple-input multiple-output (MIMO) antenna system tailored for fifth-generation (5G) mobile terminals. Operating within the 5G frequency bands N77/N78 (3.4–3.6 GHz) and N79 (4.8–5.0 GHz), the proposed MIMO system achieves high isolation between adjacent antenna elements through slotting and self-decoupling technologies. Antenna elements are strategically positioned on two frames perpendicular to the smartphone’s main board. Each antenna element integrates a rectangular microstrip radiator on the inner frame surface, accompanied by a grounded rectangular ring on the outer frame surface. The feed line, situated atop the main board, connects to an external SMA connector located at the main board’s bottom. Measurement results reveal isolations exceeding 20 dB for the lower band and 24 dB for the higher band. The fabricated and tested MIMO antenna system demonstrates excellent agreement between simulation and measurement outcomes.