MIMO Antenna Research Articles

Metasurface inspired printed dual‑port MIMO antenna system with LP to CP conversion features for millimeter wave n260 band applications

A cutting-edge antenna system has been developed for new radio (NR) millimeter wave operating from 36.0 to 40.0 GHz frequency range 2 (FR 2) n260 band applications. This innovative system incorporates metasurface-inspired printed dual-port MIMO technology, which includes LP to CP conversion features. The positional orientation of the elements of the MIMO antenna with stacked metasurface provoked the spatial diversity. To convert linearly polarised (LP) waves to circularly polarised (CP) waves, the metasurface layer is suspended above the MIMO antenna. LP to CP polarisation conversion occurs when the conducting strip and rectangular space between strips on the substrate generate π/2 phase-shifted electric field components (Ex and Ey). The proposed stepped impedance-fed antenna elements and metasurface are fabricated on commercially available high-frequency laminates using a double-layer printed circuit board (PCB) fabrication facility. The test findings exhibit a satisfactory level of concurrence with the calculated/measured findings regarding scattering parameters, diversity performance parameters, and realized gain. The result is a highly efficient and versatile antenna system that is ideal for advanced engineering applications.

Design and performance observation of U-shapedQuadpot multiband operated MIMO antenna structure for 5G and WLAN applications using FR4 substrate with high isolation

The multiband operated four port MIMO antenna structure is presented in the manuscript. The unique U-shaped radiating patch element is considered for the analysis. Multiple iterations are taken to finalize the shape of the best structure. The DGS and parasitic patch approach helps enhance MIMO antenna performance. Four parametric studies are performed to find the best structure, varying the patch's length, breadth, parasitic patch radius and DGS. The analysis of scattering response is considered to be over 1 GHz to 14 GHz for the observation of band response. The suggested design represents a reflection coefficient of −38.092 dB and a peak bandwidth of 5.78 GHz. The proposed design provides a peak isolation of 60 dB and a peak E-field of 1.80 × 104 V/m. Using an FR4 substrate, the structure's response is compared with the simulated and measured. The effectiveness of the MIMO structure is checked by observing the performance of diversity parameters. The ECC value is near zero, the Negative value of TARC, the CCL is less than 0.08, the DG is near 10 dB and the MEG value is zero. The response of all diversity parameters is within the allowable range. The presented design opens a new way to target 5G and WLAN-related applications.

Efficient MIMO Antenna Design Using Metamaterials for Compact and High-Performance Communication Applications

Efficient MIMO Antenna Design Using Metamaterials for Compact and High-Performance Communication Applications

Design of a high-gain, low-ECC 2x2 MIMO antenna for 28 GHz 5G wireless communication system

In this paper, a 2 × 2 MIMO antenna with inset feed is designed for the frequency Range 2 (FR2) millimeter wave frequencies such as n257 (26-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz). The MIMO antenna is designed and fabricated using low loss Rogers RT/duroid 5880 substrate having dimension of 1.4λ 0×2.8λ 0×0.073λ 0, where λ 0 is the free-space wavelength operating at 28 GHz.The defected ground structure (DGS) minimized the surface waves current. Thus DGS are used to increased the gain and the isolation of the proposed MIMO antenna design. The gain of the MIMO antenna reported is 10.3 dBi with 97.01% radiation efficiency at 28 GHz resonant frequency. The -10 dB impedance bandwidth lies between 26.95-29.50 GHz, which covers the 5G frequency bands. The isolation is ≥28 dB and envelope correlation coefficient (ECC) is 10 −5, respectively, in the complete operating band.

Machine learning-based technique for directivity prediction of a compact and highly efficient 4-port MIMO antenna for 5G millimeter wave applications

Miniaturized Millimeter Wave (mm-wave) MIMO antenna arrays with an observed 10-dB impedance broad bandwidth of 3.7 GHz (25.785–29.485) are the focus of this study's design and analysis for a 5G application. Rogers RT/duroid 5880, a low-loss dielectric material, is utilized in the antenna's fabrication. For MIMO antenna design down to the lowest frequency, the substrate and ground must have dimensions of 3.3λ0 × 3.3λ0. Besides compact, the suggested design has a supreme gain of 8.9 dB, isolation greater than 29.24, and a maximum efficiency rating of 98.4 %. A Diversity Gain (DG) has a value that is greater than 9.99, whereas an Envelope Correlation Coefficient ECC) has a value that is less than 0.00005. The effectiveness of machine learning (ML) models can be estimated using a variety of different metrics, including the variance score, R square, mean square error (MSE), mean absolute error (MAE), and root mean square error (RMSE). Out of the five ML models, the one that has the greatest accuracy and has a low margin of error when predicting directivity is the Random Forest Regression model. In conclusion, the data from the CST and ADS modeling as well as the actual and expected outcomes from machine learning demonstrate that the recommended antenna is a potential candidate for use with 5G.

Compact high gain and high isolation AMC-coupled MIMO antenna for wideband 5G millimeter wave applications

Compact high gain and high isolation AMC-coupled MIMO antenna for wideband 5G millimeter wave applications

Low-profile MIMO antenna for sub-6G smartphone applications with minimal footprint: an SVM-guided approach

Low-profile MIMO antenna for sub-6G smartphone applications with minimal footprint: an SVM-guided approach

Highly isolated electrically compact UWB MIMO antenna for wireless communications applications

A multiple-input multiple-output Ultra-Wide Band (UWB) antenna with a compact size of 0.8λ x 0.7λ is proposed. The presented structure is constituted with patch geometry on a planar surface. The radiator consists of three counter U-shaped conducting strips united with a patch structure where two are positioned nearby and the third geometry covers the remaining conducting strips. A corrugated design has been created on a ground plane in which zigzag pattern slots are engineered to receive high isolation of more than 20 dB. The configured antenna radiates over a wide frequency spectrum of 3.10 GHz–11.85 GHz. It offers a fractional bandwidth of 195 % with a gain of 2.80 dBi, 3.08 dBi, and 2.72 dBi for targeted resonances. The antenna radiation patterns and MIMO diversity parameters are also presented. The acceptable values of ECC (<0.05 abs), MEG (−6 dB to −8 dB), CCL (<0.02 bits/sec/Hz) were found. The fabricated model was tested inside an anechoic chamber environment to receive the measured response with optimum accuracy through multiple iterations. The measured response shows a strong correlation with numerically computed responses finding the presented antenna suitable for WiMAX, WLAN (max protocol) and radar applications.

Design of a Funnel-Shaped MIMO Antenna for RADAR Applications

Design of a Funnel-Shaped MIMO Antenna for RADAR Applications

Dual band high gain circularly polarized frequency tunable silicon-graphene based MIMO antenna for THz wireless applications

Abstract The two-port aperture linked silicon-graphene radiator in THz regime is investigated in this study. The primary characteristics of the radiator design are as follows: (i) a perturbed circular aperture that offers two working spectrums, 2.85-3.58 THz and 2.31-2.45 THz, with the support of a circular E-field within the two operating bands; (ii) an aperture mirror arrangement that enhances polarization diversity and raises the isolation level to over 25 dB; and (iii) a graphene layer over the ceramic that allows for tunability in the entire working band as well as a circularly polarized frequency range. The broadsided radiation pattern is produced by the dual hybrid mode, or HEM11δ and HEM12δ. A metallic reflector positioned underneath the radiator enhances the dual working spectrum's gain value, or around 7.5 dBi. With the aid of CST-MWS software, the final results are confirmed. The developed radiator may be used for a variety of wireless applications in the THz domain thanks to its stable far-field pattern and strong diversity parameter values.&amp;#xD;

Design and analysis of low-profile quad element wide band MIMO antenna with efficient isolation for C and X-band applications

ABSTRACT A low-profile, quad-element multiple-input/multiple-output (MIMO) antenna of 0.69 λ 0 λ 0 is presented in this study. The proposed design consists of a stub and slot-loaded partial ground plane with a quad rectangular-shaped radiator on top. The four elements are placed orthogonally to one another to reduce mutual coupling and envelope correlation coefficient (ECC). The maximum isolation of the proposed MIMO antenna is 61.5 dB at 9.94 GHz frequency. It achieved impedance bandwidth 5.56 GHz, ranging from 5.74–11.30 GHz. The peak gain of the proposed MIMO antenna is 6.18 dB at 7.3 GHz, with a maximum efficiency of 89.21% at 7.1 GHz. The minimum ECC between ports 1 and 2 over the operating band are observed as 0.0001. To achieve the best outcome, a parametric analysis of the proposed antenna is also performed. Various diversity characteristic metrics, including diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), channel capacity loss (CCL), and ergodic channel capacity (CC), are thoroughly analysed to determine how well the MIMO antenna performs in terms of diversity. Over the operating band, the measured values provide good agreement with respect to simulated and equivalent circuit model results, indicating a strong candidacy for operation in the investigated bands. The proposed MIMO antenna have the potential for C and X band applications such as WLAN, radio astronomy, satellite communication, and automotive radar.

Isolation enhancement of a capacitively-fed MIMO antenna using a quasi-fractal parasitic element and defected ground structure

Vehicular Internet of Things (IoT) is facilitated by efficient RF front ends with suppressed mutual coupling for enhanced spatial diversity and increased channel capacity. This paper presents a mutual coupling suppressed MIMO antenna with a hybrid decoupling technique for Vehicle-to-Everything (V2X) communications, enabling IoT in automotive systems. The single elements consist of a radiating patch with a cleaving circular slot to introduce a capacitive effect on the radiating structure. Afterwards, the single-unit design is further extrapolated to a 2 × 2 MIMO antenna. The mutual coupling is suppressed between antenna elements by introducing a quasi-fractal parasitic element and a defected ground structure (DGS). The MIMO antenna is designed to conform to the requirements posed by V2X systems in Dedicated Short-Range Communications (DSRC) and Intelligent transportation system (ITS) scenarios. The proposed MIMO antenna offers measured |S11| < −10 dB of 200 MHz, ranging from 5.77 GHz to 5.97 GHz, fully covering the spectrum guided by the IEEE 802.11p standard. A physical prototype is fabricated and placed on a car roof to assess the congruency between measured and simulated results. The MIMO antenna exhibits exceptional diversity properties, such as enhanced isolation (>28 dB) between its individual elements, a diversity gain (DG) close to the ideal value of 10 dB (9.99 dB), peak realized gain of 6.5 dBi, an ECC below 0.001, and a beam coverage area of 180° in azimuthal and elevation plane by dynamic port switching. Thus, the proposed MIMO antenna module is a considerable candidate for future V2X communication paradigms.

Wideband and High Gain Elliptically-inspired 4 × 4 MIMO antenna for millimeter wave applications

An elliptically-inspired microstrip antenna is utilized in this paper to operate in the V-band (52.9 – 70 GHz) of the millimeter frequency range for 5G applications. 2-port and 4-port multi-input-multi-output (MIMO) configurations are designed, fabricated, and tested to validate the desired radiation and impedance characteristics. The measured results mimic the simulated ones in terms of scattering parameters, and MIMO parameters. Although the 4-port footprint is considered miniaturized (26 × 26 mm2), it provides a reduced coupling between ports (≤ 20 dB) with an improved gain ranging from 8 to 10.1 dBi. Furthermore, the achieved MIMO parameters (ECC, DG, CCL, and MEG) are distinct with values of 0.006, ≥ 9.96 dB, ≤ 0.4 bits/s/Hz, and -3 dB, respectively. The introduced 4-port MIMO antenna is compared with the state-of-the-art antennas and this assures that the suggested model has built-in size, wider impedance bandwidth, and higher isolation with an improved diversity characteristic confirming the possibility of the presented MIMO antenna to be a challenging candidate for 5G wireless communications.

Antenna Optimization Using Metamaterials

Abstract Metamaterials are artificial structures engineered to exhibit electromagnetic properties not found in natural materials. These materials offer a diverse range of characteristics, including negative refractive index, reverse radiation, and electromagnetic cloaking. These unique properties find applications in microwave and optical domains, enabling improvements in antenna performance, the design of microwave filters, and the creation of flat optical lenses, among others. This study focuses on utilizing metamaterials to enhance antenna performance by boosting gain, reducing mutual coupling between MIMO antennas, converting polarization, and decreasing radar cross-section (RCS). The primary performance metric considered in this investigation is gain enhancement.

Performance improvement of THz MIMO antenna with graphene and prediction bandwidth through machine learning analysis for 6G application

This article provides the findings of a study that integrated simulation, an RLC equivalent circuit, and machine learning (ML) techniques to improve wireless indoor communications clusters with future 6 G applications. The antenna being presented is constructed on a polyimide substrate. It exhibits an isolation of 27 dB and has a bandwidth of 4.331 THz, ranging from 0.631 THz to 4.962 THz. Along with its small size (95.52 × 227.24) µm2, it boasts an impressive maximum gain of 13.3 dB and an efficiency rating of 95 %. The ECC value drops below 0.0002 when the DG goes over 9.99. An advanced design system (ADS) creates a model like the proposed MIMO antenna to compare the return loss caused by CST (Computer Simulation Technology). Subsequently, following extensive data sampling with CST MWS (Microwave Studio) simulation, we employed supervised regression ML techniques. Gaussian process regression demonstrates exceptional accuracy, reaching almost 99 %, as evidenced by the high R-square and var scores. Additionally, it achieves the lowest error, less than one, while predicting bandwidth. The proposed antenna demonstrates strong potential as a formidable contender for 6 G THz band applications, as evidenced by the outcomes of the CST simulations and the prognostications derived from the machine learning techniques.

A Four Port Flexible UWB MIMO Antenna with Enhanced Isolation for Wearable Applications

This article presents a four-port multiple-input-multiple-output (MIMO) flexible antenna design for Ultrawideband (UWB) application using Polydimethylsiloxanes substrate. The single UWB antenna structure consists of modified circular radiator with elliptical slot and partial ground plane. To achieve high isolation among antenna element, a Defective Ground Structure (DGS) is adopted to decouple the low frequency band. DGS comprises a centrally placed square shape slotted structure connected by horizontal and vertical lines, achieving isolation below -20 dB. The proposed antenna has a dimension of , bandwidth of 3.4–11.8 GHz (110.5%) and 4.3 dBi peak gain. Simulation and measurement findings show that the antenna performs well under bending situations with different curvature radius. At 4 GHz and 8.1 GHz, W/kg specific absorption rate (SAR) for 1/10 g tissue is examined. A low value of SAR is obtained at both the resonating frequencies. Additionally, an analysis is conducted on the diversity parameters, and the antenna demonstrates comparatively good results having mean effective gain (MEG) ratio < -3 dB envelope correlation coefficient (ECC) < 0.02, total active reflection coefficient (TARC) < − 10 dB, channel capacity loss (CCL) < 0.3 bps/Hz, and diversity gain (DG) > 9.99 dB, implying that it's appropriate for wearable MIMO applications.

A Wideband Circularly Polarized SIW MIMO Antenna Based on Coupled QMSIW and EMSIW Resonators for Sub-6 GHz 5G Applications

A Wideband Circularly Polarized SIW MIMO Antenna Based on Coupled QMSIW and EMSIW Resonators for Sub-6 GHz 5G Applications

Dual-Band and Wideband Self-Decoupled MIMO Antennas With Four Hybrid Modes

Dual-Band and Wideband Self-Decoupled MIMO Antennas With Four Hybrid Modes

Design and Analysis of Wireless Power Transmission (2X1) MIMO Antenna at 5G - Frequencies for Applications of Rectenna Circuits in Biomedical

This research presents the design and analysis of a 5G harvesting energy Circuit (MIMO-rectenna) to receive wireless power at Sub-6 frequencies (5.6 GHz) as a power source for some medical devices carried by a patient and moved from one place to another, whether they are diagnostic or therapeutic devices. This concept aims (MIMO-rectenna) to increase the likelihood of obtaining electricity from the ambient field by harvesting energy at 5G- frequencies. The tiny MIMO (2x1) antenna measuring 30 by 40 mm2 is the antenna portion of this rectenna. It has been built and tested to operate at Sub-6 frequency, or 5.6 GHz, for wireless power transmission applications related to 5G technology. The MIMO antenna has parameters of E = 4.4, h = 1.6 mm, and tand = 0.025 when printed on an FR4 substrate. A significant section of the antenna's rear was removed to carry out the broadband process, and the material's front side was composed of a series of circular slits. In this antenna, the parasitic approach was employed to decrease the mutual coupling between two ports by creating an inverted T with precise dimensions. The CST software 2024 was used to assist with the design and simulation results of this MIMO antenna. It was discovered through the simulation that the mutual coupling for these ports, 𝑆12and 𝑆21, is equal to -51.476 dB, and that the S-parameters, 𝑆11, 𝑆22, equal -22 dB. That is, there is very little signal loss while switching from the first port to the second and vice versa. This antenna's rectifier comprised an AC-to-DC conversion circuit, a DC filter, and an impedance-matching network. With the use of ADS software 2024, this rectenna's design and simulation results were completed. The greatest conversion efficiency of this rectenna at the frequency of 5.6 GHz is determined to be between 65 % and 65.01% for load resistance between 12 KΩ and 15 KΩ at an input power of 14 dBm.

Mobile-integrated SRR-based four-port MIMO antenna for broadband mm-wave 5G applications

ABSTRACT A low-profile, single-layered, compact-size, highly-isolated four-port MIMO antenna integrated within a 5 G smartphone has been proposed for a futuristic mm-wave broadband communication system. The proposed MIMO antenna configuration has been derived from a conventional inset-fed rectangular microstrip patch by introducing two parallel I-shaped slots on the patch surface for operating over a wide bandwidth of 4.91 GHz, that is, from 26.78 to 31.69 GHz. The antenna geometry has an overall dimension of 20.9 mm x 20.9 mm x 0.787 mm. The proposed configuration attained a maximum gain of 8.11 dBi and radiation efficiency of 90% at 28 GHz resonating frequency. The integration of the square-shaped SRR structure among closely packed antenna elements has significantly enhanced the overall isolation by 13 dB without compromising the antenna’s physical dimensions. The realisation of the S-parameters has also been carried out from the equivalent circuit model to agree with the results obtained from the electromagnetic simulation through CST software. The measured radiation patterns assured the minimal variation with simulated characteristics along the E and H planes. A comprehensive safety investigation of the proposed MIMO antenna has been carried out to assess power densities (<10 W/ m 2 ) across different usage modes, including data, reading, and talking in a mobile application perspective. Several diversity parameters, including ECC (<0.0001), DG (>9.999 dB), CCL (<0.12 bits/sec/Hz), MEG, and TARC, have also been evaluated as performance metrics. Furthermore, the linear transmission property of the proposed MIMO antenna has been validated through the variation of group delay (<0.5 ns) over operating frequency bands in the far-field region.