Dual-band Multiple-input Multiple-output Antenna Research Articles

A dual band CPW-fed MIMO antenna for fifth generation application

This paper presents an innovative integrated dual-band multiple-input multiple-output (MIMO) antenna for the global system for mobile communications band, fed by a coplanar waveguide. The distinctive aspect of this antenna design is its configuration, wherein all the MIMO antenna’s unit cells are placed orthogonal to one another. As a result, there is no need for additional isolation elements to achieve high isolation, simplifying the antenna’s fabrication process. The capability to operate in two frequency bands 3.5 GHz (Wi-Max) and 5.5 GHz (WLAN) is attained by integrating a curved form into the antenna’s radiator elements. Fabricated on an affordable FR-4 dielectric substrate measuring 64 × 64 × 1.6 mm3, the MIMO antenna demonstrates isolation exceeding 18 dB and an envelope correlation coefficient (ECC) of below 0.03. Experimental results from the fabricated four-port dual-band MIMO antenna configuration align with the outcomes of the 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.

Side-edge dual-band MIMO antenna system for 5G cellular devices

An eight-element multiple-input multiple-output (MIMO) antenna system is presented for two distinct 5G allocated bands, i.e., 3.5 and 5.2 GHz. The MIMO radiating elements are printed on each side of the mobile phone chassis, having dimensions of 150 × 7 mm2, while the microstrip feeding lines fed through a coaxial connector are printed on the main board, having dimensions of 150 × 75 mm2. The single element of the MIMO antenna system consists of a modified slotted rectangular patch radiator. One slot is composed of a hybrid shape (which consists of both T- and L-shaped patterns), and the second one is a typical inverted L-shaped slot. The placement of slots generated two different current paths, which led to dual-band response at 3.5 and 5.2 GHz. In the MIMO configuration, the arrangement of radiating elements ensures pattern diversity characteristics, which are useful for MIMO systems. Furthermore, the MIMO antenna system offers a minimum isolation of 13.5 and 21.5 dB at 3.5 and 5.2 GHz, respectively. From the results, it is also observed that the radiating elements offer a radiation efficiency of ≥70% at 3.5 GHz, while at 5.2 GHz, the radiation efficiency is noted to be >55% with acceptable gain. A comprehensive analysis of key performance parameters, e.g., envelope correlation coefficient (ECC), mean effective gain (MEG), and channel capacity (CC), was conducted, and it is noted that the proposed MIMO antenna system exhibits an ECC of less than 0.015, MEG of < −3 dB, and CC of 39.5 bps/Hz. In addition, the specific absorption rate (SAR) analysis of the proposed MIMO antenna was conducted and observed a value of 1.35 and 1.05 W/Kg at 3.5 and 5.2 GHz, respectively. To verify the computed results, a prototype of the proposed MIMO antenna was fabricated and subjected to thorough measurements. It was observed that the measured results satisfied the simulated data and aligned excellently with the measured data. Based on the performance of the proposed MIMO antenna, it became evident that the MIMO antenna structure can be used as a potential candidate for future fifth-generation (5G)-enabled smart phones.

Dual-Band MIMO Antenna with Four CPW Elements using Polarization Diversity for 5G Mobile Communication Networks and Satellite

In this paper, a novel design of compact quad-element MIMO (Multiple Input Multiple Output) antenna for 5G communication networks and satellites is proposed. The four similar elements of this antenna are placed perpendicularly to each other on a 40x40 mm2 FR4 substrate. Each element is fed by a CPW (coplanar waveguide) line. Two slits and an I-shaped slot are etched into the patch, and by varying their parameters; a good matching is achieved in the lower (4.9 GHz) and upper (17 GHz) frequency bands. However, 25 and 30 dB isolations are attained in the lower and upper bands, using the polarization diversity technique and adding stubs on the ground plane. A prototype of the proposed antenna is fabricated and measured. Moreover, the performance of the MIMO antenna is studied in terms of ECC (envelope correlation coefficient), DG (diversity gain), TARC (total active reflection coefficient), realized gain, efficiency, and radiation pattern, validated with the measured results, and showed a good agreement.

Compact highly isolated dual-band 4-port MIMO antenna for sub-6 GHz applications

In this work, a compact 4-element multiple-input multiple-output (MIMO) antenna system is presented for sub-6 GHz applications. A modified M-shaped strip is used to form each antenna element in the MIMO system. To improve performance, a rectangular-shaped area is etched on the opposite side of each element in the ground plane. The antenna size is 100 × 60 mm2. Most interestingly, the port isolation is improved by rotating the etched areas and the corresponding radiating elements. This one-of-a-kind approach aided in the development of a highly isolated MIMO antenna with a small footprint. The theory of characteristic modes (TCM) is used to analyze the behavior of rotating the etched areas in the ground of the antenna. The antenna provides significant port isolation above 20 dB, stable radiation patterns, and an outstanding ECC less than 0.01. The design is simple and compact, making it suitable for MIMO operation in handheld devices.

28/38 GHz dual-band MIMO antenna with wideband and high gain properties for 5G applications

In this paper, a novel high gain 4-element dual-band multiple-input multiple-output (MIMO) antenna is proposed for fifth generation (5G) wireless applications. A crescent shape is created initially from a circular structure and then the proposed antenna is formed by using slots and Defected Ground Structures (DGS) to set resonances at the desired frequencies. The proposed MIMO antenna operates both at 28 GHz and 38 GHz frequencies. In addition, the MIMO antenna has 3.05 GHz and 2.41 GHz bandwidth at those frequencies, respectively. The antenna elements are orthogonally placed to each other as a design concept to enhance the isolation between the elements up to 30 dB. Moreover, the MIMO antenna has maximum measured gains of 8.14 dB and 8.04 dB at 28 GHz and 38 GHz, respectively. The antenna size achieves compactness with the total size of 60 × 60 × 0.508 mm3. The designed MIMO antenna is also evaluated in terms of important MIMO parameters such as diversity gain (DG), envelope correlation coefficient (ECC), mean effective gain (MEG), and channel capacity loss (CCL). The proposed antenna is a great candidate for modern 5G applications that require both wideband and high gain properties with its MIMO antenna parameters of DG, ECC , MEG and CCL.

Mutual Coupling Reduction in Dual-Band MIMO Antenna Using Parasitic Dollar-Shaped Structure for Modern Wireless Communication

A dual-band Multiple Input Multiple Output (MIMO) antenna with low mutual coupling is analyzed and studied for Fifth Generation (5G) Sub-6 GHz and Wireless Fidelity (Wi-Fi) 6E frequency-band applications. Each of the identical monopole radiators consists of a rectangular patch, inverted-E, and asymmetrical T-shaped strip to generate 5G Sub-6 GHz and Wi-Fi 6E frequency bands. The deployment of the radiators horizontally with end-to-end separation of 5mm makes the antenna compact with an overall dimension of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$45\times 30$ </tex-math></inline-formula> mm2 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.37\lambda \times 0.25\lambda $ </tex-math></inline-formula> for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> at the lower resonating frequency of 2.5GHz). The antenna achieves measured impedance bandwidths of 2.39-2.57 GHz and 3.82-6.95 GHz, respectively, at two resonating frequencies of 2.5 GHz and 4.5 GHz. A Parasitic Dollar Shaped Structure (PDSS) introduced between the two monopole radiators to suppress the surface waves of each monopole reduces the measured mutual coupling up to -15 dB throughout the operating band. Furthermore, the measured gain, radiation efficiency, Envelope Correlation Coefficient (ECC), and Diversity Gain (DG) values remain in good agreement with simulated values and are well within the minimum limit set by industry standards. These results affirm the applicability of the MIMO antenna for 5G and Wi-Fi 6E frequency bands.

High isolation metamaterial-based dual-band MIMO antenna for 5G millimeter-wave applications

This article presents a high-isolation metamaterial-based dual-band multiple-input multiple-output (MIMO) antenna for 5G millimeter-wave communication networks. The proposed antenna is a pentagon-shaped monopole that provides a dual-band response with a wide operating bandwidth at 5G 28/28 bands. The antenna is printed on 0.508-mm-thick Rogers RT5880 substrate of relative permittivity ɛr = 2.2. It exhibits a small physical size of 5.5 × 5.4 × 0.508 mm3, excluding the feeding line. The MIMO system is constructed of two symmetric radiating elements arranged adjacently with the mutual coupling of −18.5 dB at both resonant frequencies. The dual-band metamaterial is designed and placed between the two radiators to reduce the mutual coupling. Embedding a 3 × 1 metamaterial array enhances the isolation to −39 dB and −38 dB at 28 GHz and 38 GHz, respectively. The proposed system is capable of covering both 28/28 5G bands and has the merits of broad bandwidth, low profile, high gain (>5 dB), improved isolation (−38 dB), low envelope correlation coefficient (ECC) (<0.0001) and channel capacity loss (CCL) (<0.05), and high diversity gain (DG) (>9.99 dB). The system performance is verified experimentally with good agreement between the simulated and measured data. These properties demonstrate the system applicability for 5G millimeter-wave communication networks.

Integrated dual‐band multiple‐input multiple‐output antenna module using higher mode control for 5G applications

This study presents a self-decoupled and highly integrated multiple-input multiple-output (MIMO) antenna pair for the 3.5 GHz (3.4–3.6 GHz) and 5 GHz (4.8–5 GHz) frequency bands, where a loop-type antenna and a dipole-type antenna are assembled into the front and backside of a compact modular board. A tuning inductor and a tuning capacitor are employed in the loop-type antenna and the dipole-type antenna, respectively, for higher mode resonance control, such that the dominant mode and higher mode of each antenna element are excited to achieve dual-band operation. Herein, the dominant modes of the loop-type antenna and the dipole-type antenna are orthogonal to each other, contributing to the self-decoupling effect in the lower band. Otherwise, the modal orthogonality of the higher modes of the two antennas is responsible for the high-isolated performance of the higher band. In this way, the proposed dual-band MIMO antenna module obtains a high spatial utilization ratio, even though they are disposed of in the same volume. The MIMO antenna module can produce impedance bandwidths above 200 MHz at both frequency bands, and the isolation within the lower and higher bands is above 16.5 and 13.5 dB, respectively. Additionally, an 8 × 8 MIMO antenna array is further constructed and measured. In measurement, the total efficiencies are higher than 60%, and the envelope correlation coefficient values are all below 0.1. Therefore, it is demonstrated that the proposed technique can be promisingly applied in large-scale MIMO antenna systems for current and future terminal devices, having advantages in multiband operation, high integration, and inherent isolation.

Isolation enhancement in dual-band MIMO antenna by using metamaterial and slot structures for WLAN applications

A dual-band multiple-input multiple-output (MIMO) antenna with enhanced isolation operating in 2.35–2.50 GHz and 5.13–5.88 GHz bands is investigated and presented. The proposed antenna system is deformed from two inverted-F antennas, and the distance between the antenna elements is only 0.104 (—wavelength of 2.4 GHz). To enhance isolation and reduce mutual coupling, the metamaterial and slot structures are efficiently and innovatively designed on the ground plane for two bands. Both decoupling methods effectively improve the antenna isolation, with metamaterials acting on the lower band and slots acting on the higher band. The mutual coupling at 2.4 GHz and 5.5 GHz is reduced by 15.24 dB and 8.19 dB, respectively. Then, the optimized MIMO antenna can cover both 2.4 GHz and 5 GHz wireless local area network (WLAN) bands, and has the advantages of wideband, compact size, good radiation, enhanced isolation, and low envelope correlation coefficient. The measured results agree with the simulated results, which shows that the proposed MIMO antenna system has potential application value in WLAN system.

Orthogonal mode dual band MIMO antenna system for 5G smartphone applications using characteristic mode analysis

PurposeThe purpose of this paper is to provide a miniaturized antenna design for a mobile phone. The second design is 2 × 4 elements multiple-input multiple-output (MIMO) antenna with 8 port having a substrate size is 20 × 40 mm2 which fits easier within smartphone handset devices for fifth generation technology.Design/methodology/approachIn this work, the first design is a conventional patch antenna, and its dual-band characteristics are obtained by characteristic mode analysis. In this method, orthogonal modes are carried out for 28 GHz and 38 GHz, and further, both orthogonal modes are excited by finite integration technique full-wave method with 50 Ohm single port coaxial feed line.FindingsIn this configuration, better return loss, high gain, larger bandwidths and low envelope correlation coefficient (ECC) are evaluated by the full-wave simulation computer simulation technology (CST) studio suite.Originality/valueIn this arrangement, the performance metrics of the antenna are analyzed using electromagnetic simulator CST Studio suite.

Dual-band Directional MIMO Antenna for WLAN Application

In this paper, we propose a dual-band directional multiple input multiple output (MIMO) antenna, which covers 2.4 / 5.8 GHz frequency band for WLAN. The MIMO antenna consists of four monopoles with the same structure and orthogonal positions, and the port isolation between the monopoles is greater than 13 dB. The monopole antenna generates double-frequency radiation by L-shaped branches and adopts a CPW feed network to achieve broadband matching. Our simulation results show that the antenna has wide bandwidth and excellent radiation performance for indoor WLAN signal distribution.

Design of Compact High-Isolation MIMO Antenna With Multiobjective Mixed Optimization Algorithm

Integrating particle swarm optimization (PSO) and binary PSO into multiobjective evolutionary algorithm based on decomposition (MOEA/D) by group operator in parallel, an improved mixed optimization algorithm MOEA/D-M is proposed as an automation design scheme for compact high-isolation multiple-input–multiple-output (MIMO) antenna design. When the algorithm runs, each particle has several neighboring particles and all the particles are subdivided into a few groups. Both groups and neighborhoods provide helpful or potential information to their members. Then, under predefined constraints, MIMO antenna with anticipated performance can be generated intelligently and targetedly. The effectiveness of this design scheme is demonstrated by a single-band and a dual-band compact high-isolation MIMO antenna design for wireless local area network (WLAN)/world interoperability for microwave access (WiMAX) applications sharing the same initial reference model. The design degree of freedom of MIMO antennas may be increased greatly with the proposed design technique.

Design of a compact hexagonal structured dual band MIMO antenna using orthogonal polarization for WLAN and satellite applications

In this paper, a compact dual band multiple-input multiple-output (MIMO) antenna system for WLAN and X-band satellite applications (2.4/9.8 GHz respectively) is proposed. On the top face of the substrate, two antenna elements with a size of 20 × 24 mm2 are placed side by side and fed with matched orthogonal micro-strip lines. The two antenna elements have orthogonal polarization which can reduce the mutual coupling between its ports. The designed antenna system is fabricated and measured to validate the simulation results. The impedance bandwidths are about 370 MHz (2.19 to 2.56 GHz) and 630 MHz (9.44 to 10.07 GHz), while the obtained isolation is greater than 14 dB at the operating bands. Furthermore, the envelope correlation is less than 0.052 and 0.008 at 2.4 and 9.8 GHz, respectively. Hence the diversity gain is higher than 9.98 in the frequency bands of interest.

Design of a compact dual-band MIMO antenna with high isolation for WLAN and X-band satellite by using orthogonal polarization

ABSTRACT This paper presents a new design of a compact dual-band Multiple Input Multiple Output (MIMO) antenna with high isolation for WLAN and X-band satellite applications. The proposed antenna is realized using three slots: the first slot is used on the upper layer to create the second resonance frequency at 5.3 GHz and two symmetrical slots are etched on the bottom layer to enhance the impedance bandwidth of the two operating bands. In order to obtain a low mutual coupling, the two antenna elements have an orthogonal polarization. The simulated results show that the MIMO antenna has a high isolation (S21 ≤−22.5 dB) at the two desired bands with impedance bandwidths are about 4.15% (5.19–5.41 GHz) and 4.81% (7.30–7.66 GHz). In addition, the MIMO parameters like envelope correlation coefficient (ECC), diversity gain (DG), Total Active Reflection Coefficient (TARC), realized gain and efficiency are also analyzed.

Multiband MIMO Microwave and Millimeter Antenna System Employing Dual-Function Tapered Slot Structure

A single-layered multiple-input multiple-output (MIMO) antenna system is presented for future wireless devices operating at WLAN (2.45 GHz, 5.2 GHz), 4G LTE (2.6 GHz) and 5G (24 GHz, 28 GHz) bands. The design consists of a dual-band four-element monopole MIMO antenna system that covers the 2.45 GHz and 5.2 GHz bands. A decoupling mechanism is designed in the ground plane based on a tapered slot. This tapered slot has a dual function, working both as a decoupling structure ( $\lambda _{0}/4$ long) at 2.45 GHz and as a tapered slot antenna ( $3\lambda _{0}$ long) at 28 GHz when excited by a proper feeder. The proposed MIMO antenna system is designed on an RO-5880 substrate with overall dimensions of $104$ mm $\times 104$ mm $\times 0.51$ mm. The measured results show that the presented design covers two low-frequency bands (from 2.40 GHz to 5.1 GHz, from 5.1 GHz to 5.6 GHz) with a peak gain of 5 dBi and one high-frequency band (from 23 GHz to 30 GHz) with a peak gain of 11 dBi. The minimum measured isolation between the two antennas is more than 16 dB, while the maximum envelope correlation coefficient value is less than 0.16 showing good MIMO characteristics.

Defected ground structure loaded with meandered lines for decoupling of dual-band antenna

ABSTRACTA defected ground structure (DGS) loaded with meandered lines is proposed to reduce mutual coupling of a dual-band planar multiple-input multiple-output (MIMO) antenna. To verify the effectiveness of a proposed DGS, a dual-band MIMO antenna is designed and manufactured. The antenna consists of two planar-inverted F-antenna (PIFA) elements printed symmetrically for dual-band operation. The DGS is placed between these two PIFA elements to reduce mutual coupling. The DGS consists of a slot and a pair of meander lines inside it, hence generating two independently tuneable resonances. A two element MIMO antenna is studied using computer simulation and a final design is manufactured. The antenna is measured using the Satimo Starlab system. Simulation results show that the MIMO antenna has the bandwidths (S11 & S22<−10 dB, S21 & S12<−15 dB) of 1.56–2.71 GHz (1.15 GHz or 54%) and 4.82–5.9 GHz (1.08 GHz or 20%) in the lower and higher frequency bands, respectively. Measurement results agree well with the simulation.

Frequency reconfigurable dual-band MIMO antenna using pentagon slot resonator with improved bandwidth

In this paper, multiple-input–multiple output (MIMO) antenna with dual-band frequency reconfiguration is presented. The proposed antenna consists of two symmetrical pentagon radiating elements. These radiating elements support bands of 1.5 GHz (GPS) and 2.4 GHz (Wi-Fi) frequency. The two PIN diodes are appropriately located on slot line in order to control the current flowing through the radiator. All simulated results are compared and confirmed with measured results. The antenna has VSWR ⩽1.8 and isolation of −28 dB. The advantage of this antenna is that bandwidth is increased by switching of PIN diode in the range from 80 MHz up to maximum 300 MHz. These characteristics demonstrate that proposed antenna is an attractive solution for a multimode application such as GPS, Wi-Fi routers, vehicular communication, etc. where wideband is required.

Performance of Groundplane Shaping in Four-Element Dualband MIMO Antenna

This work presents performance of groundplane shaping and its effect in four element dualband multiple input multiple output (MIMO) antenna. This proposed four element dualband MIMO antenna consists of four bowtie dipole antenna which operates at 1800 MHz (low frequency) and 2300 MHz (high frequency). This proposed four element dualband MIMO antenna occupies a 270 x 210 x 100 mm 3 of FR 4 substrate. We use four types of groundplane pattern i.e. full groundplane, cornered spatial groundplane,crossed middle groundplane, and spiral groundplane. These various grounplane patterns influence the performance of main parameters of dualband MIMO antenna. Cornered spatial groundplane pattern yields a largest bandwidth (VSWR ≤ 2) 282 MHz or 15.24% of center frequency at low frequency. Full groundplane pattern creates 135.2 MHz at high frequency. In addition, cornered spatial groundplane pattern also generates a lowest VSWR that is valued 1.21 at both low frequency and high frequency. The S parameters, basically both cornered spatial and full groundplane pattern produce a better return loss than two others. All four groundplane patterns deliver equally a mutual coupling parameter.The last, this proposed four element dualband MIMO with various groundplane patterns gives a good farfield properties i.e. gain, radiation pattern, H-E field.

A Dual-Band Multiport MIMO Slot Antenna for WLAN Applications

A novel compact dual-band multiple-input–multiple-output (MIMO) antenna design for IEEE 802.11 applications is proposed. The antenna operates at 4.9–5.725 GHz with four ports and at 2.4–2.5 GHz with two ports and utilizes a dual-band dual-port MIMO antenna to cover the 2.4/5-GHz bands alongside two single-band antennas to cover the 5-GHz band. This allows simultaneous operation at both WLAN frequencies while having only four ports in total. Isolation between ports is better than 12 dB and is achieved with no reconfigurable elements. The overall antenna size is compact, occupying $46\,\times 20\,\times 1.6\:\mathrm{\,\text{mm}^{3}}$ , and is printed on an FR-4 printed circuit board. The proposed antenna is investigated by simulation and measurement, and results include radiation patterns, efficiency, ${S}$ -parameters, signal correlations, and branch power ratios between ports. These show that in typical wireless environments, envelope cross correlations of less than 0.3 between the ports are obtained.