5G Multiple-input Multiple-output Research Articles

Miniaturized Multi-band Millimeter-Wave Vivaldi Antenna with Performance Optimization at 28 GHz for 5G MIMO Applications

A novel design for Vivaldi antenna is introduced to operate in more than one frequency band in the millimeter-wave spectrum range with high gain. The proposed Vivaldi antenna is planar and printed on both sides of Rogers 3003C flexible substrate. A parasitic annular ring is added to each arm of the Vivaldi antenna to adjust the impedance matching and maximize the gain. The dimensions of the antenna are optimized using the CST microwave simulator to obtain the best impedance matching bandwidths and highest gain in a compact-size antenna. The 28-GHz band is then selected due to its importance to enhance the gain and improve the operating bandwidth for the 5G applications. A gain of 10 dBi and bandwidth of 6.1 GHz are obtained at 28 GHz. A multiple-input multiple-output (MIMO) antenna system is then designed for pattern diversity for the fifth-generation mobile applications. The performance of the MIMO system is evaluated regarding the envelope correlation coefficient and the diversity gain showing good results. The optimized antenna is fabricated and its return loss and radiation patterns are measured showing good consent between the simulations and the practical work. The MIMO antenna system is also fabricated, and its performance is measured regarding the reflection and coupling coefficients showing good agreement between the measurements and simulations.

Dual-band 5G MIMO antenna with enhanced coupling reduction using metamaterials

This article introduces a miniaturized dual-band multiple input multiple output (MIMO) antenna with wide bandwidth and high isolation. The design incorporates ground plane modifications and utilizes metamaterials to achieve dual-band operation in the millimeter wave spectrum for 5G applications, specifically operating at the 28/38 GHz frequency bands. The proposed antenna maintains its dual-band functionality despite its compact size of 3.8 times 3.7 times 0.787 text {mm}^3 (without the feed line). The antenna is fabricated on a Rogers RT5880 substrate with a thickness of 0.787 mm and with relative permittivity varepsilon _r = 2.2. The MIMO system comprises two symmetric radiating elements positioned in close proximity, resulting in mutual coupling levels of - 20 dB and - 12 dB at 25 GHz and 37 GHz, respectively. Modifications are made to the ground length to enhance the isolation at the higher frequency band while embedding metamaterials effectively reduces the coupling at the lower frequency band. The incorporation of metamaterials leads to an enhanced bandwidth from 3.8 to 4.8 GHz in the desired lower band (24–28.8 GHz) and from 3.8 to 4.2 GHz in the higher band (36.6–40.8 GHz). The proposed system can operate across the 28/38 GHz bands using a compact design, thus offering reasonable isolation, an envelope correlation coefficient below 0.0001, and a significant diversity gain (> 9.99 dB). These attributes emphasize the system’s suitability for 5G millimeter-wave cellular communications.

Dual-polarized 8-port sub 6 GHz 5G MIMO diamond-ring slot antenna for smart phone and portable wireless applications.

This manuscript presents high performance dual polarized eight-element multiple input multiple output (MIMO) fifth generation (5G) smartphone antenna. The design consists of four dual-polarized microstrip diamond-ring slot antennas, positioned at corners of printed circuit board (PCB). Cheap Fr-4 dielectric with permittivity 4.3 and thickness of 1.6mm is used as substrate with overall dimension of 150 × 75 × 1.6 mm3. In mobile system due to limited space mutual coupling between nearby antenna elements is an issue that distort MIMO antenna performance. Defected ground structure is used to control coupling. The defected ground structure has advantages like ease of fabrication, compact size and high efficiency as compare to other techniques. Less than 30dB coupling is achieved for adjacent elements. The -10 dB impedance bandwidth of 700 MHz is achieved for all radiating elements ranging from 3.3 GHz to 4.1 GHz. The value is about 900MHz for -6dB. The proposed antenna offers good results in terms of fundamental antenna parameters like reflection coefficient, transmission coefficient, maximum gain, total efficiency. The antenna achieved average gain more than 3.8dBi and average radiation efficiency more than 80% for single dual polarized element. The antenna provides sufficient radiation coverage in all sides. The MIMO antenna characteristics like diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC) and channel capacity are calculated and found according to standards. Furthermore, effect of user on antenna performance in data-mode and talk-mode are studied. Proposed design is fabricated and tested in real time. The measured results shows that proposed design can be used in future smartphones applications. The design is compared with some of the existing work and found to be the best one in many parameters and can be used for commercial use.

RF Packaging and Design for Development of High Performance 5G mmWave Modules

5G sub-6GHz networks have already been deployed in many regions around the world. However, the deployment of 5G mmWave networks is yet to meet expectations. This is partly because of the challenges associated with hardware development of 5G mmWave systems. One example of such a challenge is to overcome the severe degradation of signal-to-noise (SNR) ratio due to intra- and inter-system signal losses at mmWave frequencies. This deteriorates the signal quality, limits transmission distances and may lead to unreliable mobile communication. In this work, we present RF packaging platforms and technologies as well as an approach for scalability of 5G RF frontend integrated circuits (ICs) and antennas which overcome intra- and inter-system losses. This leads to the development of high-performance and scalable 5G MIMO (multiple input multiple output) modules for reliable mobile communication at mmWave frequencies. The platforms provide very short and low-loss signal paths with few geometrical discontinuities between the frontend ICs and antennas. This leads to significant reduction in signal reflections and attenuation, thus improving the matching efficiency of the antennas and the equivalent isotropic radiated power (EIRP) of the entire system. The platforms also enable antennas to be integrated on layers directly above the ICs, and thereby ensures scalability of the ICs and antennas in both lateral dimensions for 5G mmWave massive MIMO. To demonstrate the functionality of our proposed packaging platforms, technologies and antennas, we performed in-depth RF designs, measurements and characterization of packaging materials, technologies and platforms as well as antennas for 5G mmWave applications.

Power allocation algorithm for capacity maximization in 5G MIMO systems

The multiple input - multiple output (MIMO) systems have sparked a lot of research interest because of their ability to increase the system capacity without using much bandwidth. The High-Speed Train (HST) communication system's capacity was calculated by assuming that the SNR is unaffected by variations in attenuation and channel losses. Here, considering this optimization problem, a power allocation algorithm using the Water-Filling technique is proposed for the MIMO system with known Channel Side Information (CSI) at the transmitter and receiver. The presented algorithm may be efficiently optimized for improving channel capacity to achieve spectral efficiency (SE).

Self‐decoupling coupled‐fed patch antennas for 5G multiple‐input multiple‐output applications

AbstractSelf‐decoupling coupled‐fed patch antennas are designed in this letter. The self‐decoupling mechanism is based on the weak‐field region formed by the T‐shaped probe feed and the radiating patch of the antenna element itself. When another identical antenna element is placed in the weak‐field region, high isolation between the two elements can be achieved without adding extra decoupling structures. To validate the decoupling mechanism, a dual‐element antenna array is initially built and an isolation level of better than 30 dB is achieved over the impedance band of 3.3–3.66 GHz with an element spacing of 0.53λ0. Next, a four‐element multiple‐input multiple‐output (MIMO) linear antenna array is presented to further verify the decoupling method and good isolation performance is also obtained, which demonstrates that the proposed designs are good candidates for 5G MIMO applications.

Performance evaluation of polar coded neural demapper based 5G MIMO communication system by varying antenna size

This paper proposes a Polar-coded neural damapper based 5G multiple-input multiple-output (MIMO) system for M transmitting and N receiving antenna, operating in a flat fading environment. MIMO is a spatial diversity scheme to improve channel performance and mitigate troubling fading issues in urban environments. A neural network-based smart demapper is considered instead of traditional demapper to improve the system's performance. Researchers have recently focused on developing complex neural network (NN)-based demapper on generating soft information for each transmitted bit. Neural demapper also increases spectral efficiency, meaning a symbol-to-bit demapper with higher complexity. This work considers a Polar-coded MIMO 5G communication system with 2×3, 2×4, 4×6 and 4×16 transmitting and receiving antennas, respectively, to evaluate the system performance under QAM modulation (4-QAM, 16-QAM, 256-QAM) techniques. It is evident from the simulated result that our proposed system performs better for lower-order modulation techniques with an increase in the number of transmitting and receiving antenna.

Design and Optimization of Metamaterial-Based Dual-Band 28/38 GHz 5G MIMO Antenna With Modified Ground for Isolation and Bandwidth Improvement

This letter presents a high-isolation dual-band multiple-input multiple-output (MIMO) antenna based on the ground plane modification and optimized metamaterials (MMs) for 5G millimeter-wave applications. The antenna is a monopole providing a dual-band response at 5G 28/38 bands with a small physical size (4.8 × 2.9 × 0.762 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , excluding the feeding line). The MIMO consists of two symmetric radiating elements arranged adjacently with the mutual coupling of −19 dB and −17 dB at 28 and 38 GHz, respectively. Reducing the ground length enhances the isolation to 34.6 dB at 28 GHz, whereas embedding the MMs diminishes the coupling to −47 dB at 38 GHz. The trust-region gradient-based search algorithm is employed to optimize the MM structure dimensions and to enhance the isolation at 38 GHz. The MMs also contribute to the enhancement of bandwidth from 1.6 GHz to 1.7 GHz at 28 GHz (27.1–28.8 GHz) and from 2.75 GHz to 3.7 GHz at 38 GHz (35.2–38.9 GHz). The proposed system is capable of covering both 28/38 bands with low profile structure, high isolation, low envelope correlation coefficient (ECC) ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lt 0.2 \cdot 10^{-4}$</tex-math></inline-formula> ), and high diversity gain (DG) (>9.99 dB). These properties demonstrate the system applicability for 5G millimeter-wave cellular communications.

Modern 5G MIMO Antenna for Vehicular Communication and Safety

A Modern 5G Multiple Input Multiple Output (MIMO) antenna alignment with frequency range for the 5G NR-n2 band (1.81 GHz) and protection band (5.85 GHz) that are dual-band for automobile communication and safety is offered. In a relatively shrunken dimension in relation to its working wavelength, the smallest frequency of resonance is relatively challenging to attain. The antenna's dimensions are 60 mm × 60 mm × 1.6 mm and it achieves a gain of 4.65 dBi and 3.38 dBi, at the frequency range of 1.81 GHz and 5.85 GHz. Because of the presence of ground slot, MIMO antennas offer isolation values of more than 19 dB and diversity gains that are comparatively close to 10 dB. In GSM and safety applications, this enhanced square single-element and MIMO antenna offers a noticeably increased gain and improved performance. The on-vehicle study of MIMO setups is performed to ensure the durability of the specified antenna in an automotive application.

A Compact Wideband Antenna With Suppressed Mutual Coupling for 5G MIMO Applications

A novel miniaturized wideband dual-polarized antenna, based on cross magnetic dipoles and a backed cavity, is proposed in this letter for multiple-input–multiple-output (MIMO) applications. The dipoles with exponential curvature edges deliver inherent wideband character to the radiator. Four parasitic resonators are introduced to miniaturize the top radiator's conducting area and lower the Q-factor of the whole structure, enhancing the antenna's impedance matching. Different from conventional direct-fed cross-dipole antennas, a wideband hybrid ring coupler is applied to excite the two dipoles simultaneously in-phase/out-of-phase to generate the ±45° polarization. The dimension of the proposed antenna is 42.5 mm × 42.5 mm × 18 mm, which is only 0.48 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> × 0.48 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> × 0.2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ_L</i> at the frequency of 3.4 GHz. The corresponding MIMO array is studied, showing a low mutual coupling and envelope correlation coefficient level across the band, and an outperforming front-back-ratio performance. The antenna is prototyped and measured. The measurement results agree with those of the simulations well .

Millimeter-Wave Broadband MIMO Antenna Using Metasurfaces for 5G Cellular Networks

Developing a millimeter-wave (mm-wave) antenna that enables wide bandwidth with its operating band covering the entire global 5G spectrum is highly desirable but very challenging for achieving both compact size and high-performance antenna. Herein, the mm-wave microstrip patch antenna (MPA) and its multiple-input multiple-output (MIMO) configuration based on the metasurfaces for 5G system applications are proposed and investigated by the simulation method. To improve performance and keep the low-profile and low-cost MPA antenna, square ring resonator (SQRR) metasurface and radiating patch are printed on a single dielectric layer. With the presence of the metasurfaces that acting as a secondary radiator, the performance of the designed antenna is significantly improved with a wide operating band in the range of 23.9-30.7 GHz, high peak gain of 9.4 dBic, and radiation efficiency of above 87%. Based on this design, four-port MIMO antenna configuration is performed for evaluating a MIMO system that realizes the advantage features such as compact size, wide bandwidth covering the entire global mm-wave 5G spectrum band of 24.25-29.5 GHz, and excellent diversity performance characterized by good isolation between the adjacent elements and low envelope correlation coefficient. Thus, the MIMO antenna design is a very promising candidate for 5G MIMO mm-wave applications, specifically in cellular systems.

Design of a novel 5G MIMO antenna with its DGP optimisation using PSOGSA

ABSTRACT In this manuscript, the design of a high isolation Multiple Input Multiple Output (MIMO) Hybrid Fractal Antenna (HFA) has been presented for 5 G and other wireless standards in a wider operational frequency range from 1 to 30 GHz. The fractional ground plane is used for the assembly of the antenna in the initial phase, further, the T-stub has been exploited on the ground plane to expand the isolation between the radiating elements. The dimensions of the proposed antenna are optimised using the Particle Swarm Optimisation Gravitational Search Algorithm (PSOGSA). The performance parameters of the projected antenna have been measured and analysed. The obtained experimental results are highly correlated with simulated ones. Performance diversity parameters of designed antenna like CCL, DG, ECC, TARC, and MEG fall within working limits in the frequency range of interest. The developed antenna retains high isolation between −30 to−50 dB in the desired frequency range. The proposed model of an antenna can be useful for 5 G 3.5 GHz band, 5 G NR (New Radio) frequency bands (3.3–5.0 GHz), LTE band 46 (5.15–5.925 GHz), European Union 5 G frequency band (5.9–6.4 GHz), 5 G 26 GHz frequency band and other wireless standards in the frequency range from 1 to 30 GHz.

A novel design of wide and multi-bands 2×2 multiple-input multiple-output antenna for 5G mm-wave applications

In this paper, we present a new design for a multiple-input multiple-output (MIMO) antenna with four ports operating in wide and multi-millimeter-wave (Mm-Wave) bands for various 5G applications (including the internet of things (IoT), communication devices, and smartphones). The antenna is designed in a rectangular zigzag shape with slots to make the antenna operate at different frequencies. For this, the antenna operates at multiple frequencies from 38 to 62 GHz, so it supports all advanced wireless communication applications. The most important characteristic of the design is its small size and compact structure compared to designs presented by researchers in previous literature so&lt;em&gt; &lt;/em&gt;the antenna dimensions for four elements are 29×49 mm&lt;sup&gt;2&lt;/sup&gt;. The antenna performance based on the results obtained from CST Studio Suite is good since the reflection coefficients of the antenna resonate at six main frequencies are 39.128 GHz, 42.992 GHz, 47.384 GHz, 51.536 GHz, 55.472 GHz, and 59.288 GHz. In addition, the isolation value between all antenna elements is ≤30 dB and the diversity gain value for all frequencies is 10 dB. Moreover, a very small value was obtained for the envelope correlation coefficient (ECC) is &amp;lt;4.0576×10&lt;sup&gt;−11&lt;/sup&gt;. Finally, the results indicate a favorable design and potential competitor for all 5G MIMO Mm-Wave applications.&lt;br /&gt;&lt;em&gt;&lt;/em&gt;

Co‐located and space‐shared multiple‐input multiple‐output antenna module and its applications in 12 × 12 multiple‐input multiple‐output systems

AbstractIn this study, we developed a co‐located and space‐shared multiple‐input multiple‐output (MIMO) antenna module with a modular design and high integration level. The proposed antenna pair includes a half‐wavelength loop antenna and a dipole‐type antenna printed on the front and back sides of a compact modular board. Owing to their modal orthogonality, these two independent antenna elements are highly self‐isolated and free of additional decoupling components, even though they are assembled at the same location and within the same space. Thus, the proposed antenna is attractive in 5G MIMO systems. Furthermore, the proposed co‐located and space‐shared MIMO antenna module was employed in a 5G smartphone to verify their radiation and diversity performances. A 12 × 12 MIMO antenna system was simulated and fabricated using the proposed module. Based on the results, the proposed module can be employed in large‐scale MIMO antenna systems for current and future terminal devices owing to its high integration, compactness, simple implementation, and inherent isolation.

Wideband Back-Cover Antenna Design Using Dual Characteristic Modes With High Isolation for 5G MIMO Smartphone

A novel method of designing a wideband high-isolated dual-antenna pair using dual-characteristic modes (CMs) is presented for fifth-generation (5G) multiple-input multiple-output (MIMO) smartphone applications. A set of orthogonal CMs resonating from the square-loop slot is first introduced and works for the lower band. Then, another set of orthogonal CMs resonating from the edge branches is introduced with a shared compact radiator and works for the higher band. In combination with two sets of degenerated CMs and a capacitive coupling feeding structure, the proposed dual-antenna pair achieves a broad impedance bandwidth and high isolation without the need for any external decoupling structures. Based on this dual-antenna pair, an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO array is developed and integrated into the back cover of a smartphone, which realizes zero ground clearance on the system circuit board. To verify the design concept, prototypes of the antenna pair and MIMO array were fabricated and measured. It shows that experimental results agree well with the simulation results. More importantly, the presented <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO array has high isolation of more than 20 dB is achieved across the operating band of 3.3–3.8 GHz.

Four Element MIMO Antenna Systems with Decoupling Lines for High-Speed 5G Wireless Data Communication

A low-profile planar multiple-input multiple-output (MIMO) antenna consisting of four elements with isolation improvement is proposed for 5G mm Wave (24–40) GHz applications. Each radiating element of the MIMO antenna comprises of a microstrip-fed tilted spade-shaped radiator with four asymmetrical slots and a partial ground plane. The antenna is optimized to resonate at 35 GHz covering a wide impedance bandwidth from 23.9 to 40.1 GHz. Two cross lines are then loaded between the antenna elements to improve the isolation &gt; − 30 d B . The MIMO structure with the decoupling lines is fabricated and tested. The measured results are in good correlation with the simulated results. Other MIMO performance metrics such as the envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain (DG), and total active reflection coefficient (TARC) are examined, and the results are found to be satisfactory for the device to be used for mm-wave 5G MIMO applications. Also, the antenna’s performance metrics such as radiation efficiency, gain, and radiation patterns over the operating band are presented.

5G MIMO Antenna Designs for Base Station and User Equipment: Some recent developments and trends

5G multiple-input, multiple-output (MIMO) antenna systems will be an important pillar in realizing the new standard. The key advantages that MIMO provides are high data rate, low latency, and high reliable communication. The main objective of this article is to present a comprehensive review, recent trends and development of sub-6 GHz and millimeter wave (mm-wave) MIMO antenna designs for next-generation wireless communications. This work features MIMO antenna designs for both base station (BS) as well as handheld devices for 5G communications. A state-of-the-art literature review is presented to report the recent developments in sub-6 GHz 5G MIMO, integrated 4G, and mm-wave 5G MIMO, mm-wave 5G MIMO antennas, and mm-wave massive-MIMO (m-MIMO) BS antenna designs for the first time in a comprehensive manner. Moreover, the challenges associated with 5G communication are also discussed.

Over-the-Air Performance Testing of 5G New Radio User Equipment: Standardization and Challenges

The Third Generation Partnership Project (3GPP) is accelerating 5G new radio (NR) global standards aimed at significant enhancement of wireless system performance for higher date rate, better energy efficiency, and higher reliability than the current 4G cellular systems. The operators, manufacturers, and test equipment vendors have worked together to develop standardized over-the-air (OTA) test methodologies for the overall performance evaluation of 5G NR devices. 3GPP is taking the lead in standardizing the OTA testing of 5G NR under fading channel conditions. In 3GPP specifications, test methods have been studied to verify the multiple-input multiple-output (MIMO) performance of 5G NR user equipments (UEs) in OTA mode. This article follows the 3GPP standardization work and discusses the MIMO OTA test methodologies for 5G NR UEs working at frequency range 1 (FR1) and FR2, with a focus on its new challenges and solutions compared to 4G MIMO OTA testing methods. Then the OTA throughput testing results of real 5G NRUEs are demonstrated under the standard channel models. Finally, the challenges and limitations of standard 5G MIMO OTA test solutions are also highlighted.

Enhancing 5G MIMO Core Spectral Efficiency with Higher-Resolution Multi-User MIMO and Multi-Beam Operation

In this article, the evolution of two core multiple-input multiple-output (MIMO) features of the 5G New Radio standardization is described along with their motivations, salient designs, and demonstrated benefits. The first feature enables high spectral efficiency with reduced overhead and complexity in the sub-6 GHz regime by exploiting frequency-domain compression and angle-delay reciprocity inherent in high-resolution precoding codebooks for multi-user MIMO. The second feature, intended for the over-6 GHz regime, facilitates streamlined beam management with greatly reduced signaling overhead and latency as well as improved link reliability in the presence of challenging scenarios such as high mobile speed, large number of analog beams, and unpre-dictable signal blocking. The presented features are the outcome of a five-year work and expected to continue evolving to meet a growing number of challenges from new deployment scenarios.

Low-SAR Four-Antenna MIMO Array for 5G Mobile Phones Based on the Theory of Characteristic Modes of Composite PEC-Lossy Dielectric Structures

A low-specific absorption rate (SAR) four-antenna multiple-input–multiple-output (MIMO) antenna array is designed for fifth-generation (5G) mobile phones based on the theory of characteristic modes (TCM) of the composite perfect electric conductor (PEC) and lossy dielectric structures. First, the TCM of composite PEC-lossy dielectric structures is reviewed briefly. Then, the application of the theory for low-SAR antenna design is demonstrated through a four-antenna MIMO antenna array. Finally, the proposed MIMO array is fabricated, and its performance is measured. Its −10 dB impedance bandwidth can cover the desired frequency band from 3.4 to 3.6 GHz. The isolations between different antenna elements are higher than 15.4 dB. Their total efficiencies range from 81.3% to 89.9%. The envelope correlation coefficient (ECC) is lower than 0.07. The 10 g spatial-average body SAR corresponding to the situation that four antennas simultaneously radiate is 0.47 W/kg. Compared with the state-of-the-art 5G MIMO antenna arrays, the proposed MIMO antenna array has the lowest peak SAR value, satisfactory efficiency, isolation, and ECC. This article provides a general methodology for the design of low-SAR mobile phone antennas.