Multiple-input Multiple-output Antenna Research Articles

Design and Optimization of Dual Port Dielectric Resonator Based Frequency Tunable MIMO Antenna with Machine Learning Approach for 5G New Radio Application

SummaryIn this article, a dual port Multiple Input Multiple Output (MIMO) cylindrical Dielectric Resonator (DR)‐based frequency tunable antenna with a machine learning (ML) approach for a 5G New Radio (NR) application is presented. According to the author's best knowledge, it is the first time‐frequency tunable MIMO hybrid DR with ML is reported. A dual port MIMO DRA is placed in the orthogonal configuration with the connected ground to obtain higher isolation in the entire frequency range. The proposed dual port antenna provides a total spectrum (TS) and tuning range (TR) of 98.99% and 80.93%, respectively. The different MIMO parameters, Envelope Correlation Coefficient (ECC), Total Active Reflection Coefficient (TARC), and Diversity Gain (DG) are investigated and found within the acceptable limits. The optimization of the proposed dual port tunable antenna is done through the various ML algorithms, including Artificial Neural Network (ANN), K‐Nearest Neighbor (KNN), Decision Tree (DT), Random Forest (RF), and Extreme Gradient Boosting (XGB). The KNN ML algorithm provides more than 98% accuracy for predicting the S‐parameters in all configurations. Hence, the proposed antenna is suitable for 5G NR applications.

A Low-Profile four-port MIMO Antenna for 5G-n79 Band with high diversity performance

This paper presents a simple design of a compact 4-port multiple-input multiple-output (MIMO) microstrip antenna using polarization diversity technique. The proposed structure consists of four monopole elements operating in the fifth generation n79 band (4800–5000 MHz). To achieve good performance with a more compact design, the four identical elements are arranged orthogonally to each other. The proposed antenna is fabricated using a Rogers RT6010 substrate with a compact size of 28 × 28mm2. The measured results of the manufactured antenna in terms of S-parameters and radiation pattern are in good agreement at the operating frequency band. Moreover, the diversity performance of the proposed MIMO antenna is evaluated through the envelope correlation coefficient (ECC), the diversity gain (DG), the total active reflection coefficient (TARC) and the channel capacity loss (CCL).

High-performance MTM inspired two-port MIMO antenna structure for 5G/IoT applications

Abstract This study thoroughly investigates a two-port multiple-input multiple-output (MIMO) antenna system tailored for 5G operation at 28 GHz. The proposed antenna is patched on a Rogers (RT5880) substrate with a relative permittivity of 2.2 and total size of 20×12×0.508 mm3. The mutual relationship between the radiating patches is refined using an H-shaped metamaterial structure to reduce the isolation to –55 dB. A MIMO configuration with attractive features is employed to reduce the envelope correlation coefficient (ECC) to about 0.00062 and the channel capacity loss (CCL) to about 0.006 bits/sec/Hz, while magnify the gain to about 9.39 dBi and the diversity gain (DG) to about 9.995. Additionally, it boasts a compact size with stable radiation pattern. The simulations of the MIMO antenna are executed using CST microwave studio, subsequently validated with Advanced Design System (ADS) for an equivalent circuit model, then measured using Vector Network Analyzer. Discrepancies between measured and simulated results were analyzed, with observed variations attributed to cable losses and manufacturing tolerances. Despite these challenges, a comprehensive comparison with prior research highlights the notable advantages of the proposed design, positioning it as a compelling solution for 5G applications.

High gain multi-band circularly polarized wearable leaky wave zipper MIMO antenna

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 (<-23 dB) between each port. Since the antenna's characteristics do not change significantly under bending and when the zipper is opened, the proposed antenna is a viable candidate for body-centric wireless communications on the battlefield. For example, it can facilitate communication covering wireless local area network (WLAN) and fifth-generation (5G) communications.

A 4-port flexible MIMO antenna with isolation enhancement for wireless IoT applications

This paper presents a conformal, miniaturized, and geometrically simple monopole antenna designed for Vehicle–to–Everything (V2X) communications. The antenna consists of a flexible substrate, radiating patch, ground, and metallic stubs. Meandered lines are added to the U-shaped radiator to achieve the required bandwidth of the antenna. The antenna has |S11|< −10 dB magnitude from 5.06 to 7.24 GHz, attaining a peak low magnitude of–68 dB. The antenna is configured into a 4-port Multiple–Input–Multiple–Output (MIMO) setup to minimize the mutual coupling between its elements. The proposed flexible MIMO antenna offers bandwidth from 5.37 to 7.34 GHz and a peak moderate gain of 4.63 dBi with omnidirectional stable radiation patterns. To improve the mutual coupling, two hollow concentric circular structures, in combination with a pair of stub networks are integrated between the elements of the MIMO system. The transmission coefficient and surface current analysis confirm the effectiveness of the decoupling structure. The presented MIMO antenna is characterized by high isolation, a low envelope correlation coefficient (ECC), and high diversity gain, suitable for V2X MIMO communication scenarios.

Metasurface loaded ceramic based MIMO antenna with improved gain and circular polarization characteristics

In this communication, the conceptualization involves the design of a multiple input multiple output (MIMO) (dual-port) ring dielectric resonator antenna and the integration of a meta-surface onto this configuration. It introduces three distinctive attributes, which characterize the novelty of the proposed design: (a) facilitates the conversion of linearly polarized waves into circularly polarized counterparts; (b) contributes to a substantial enhancement in gain in between the working band; and (c) there is notable improvement in the isolation between the antenna ports to more than 25 dB. The experimental measurements validate the simulated results of proposed design and confirms its applicability in between 2.45–3.0 GHz. Notably, a 3-dB axial ratio is created in the frequency span of 2.56–2.99 GHz, along with an impressive gain of approximately 8.3 dBi. Its consistent radiation pattern and excellent diversity performance make it suitable for WiMAX (2.6 GHz) use.

High Isolation MIMO Antenna System for 5G N77/N78/N79 Bands.

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.

A slotted frustum-shaped 4 × 4 MIMO dielectric resonator antenna with enhanced isolation for 5G Wi-Fi applications

In this paper, a slotted frustum-shaped 4 × 4 multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is designed and developed for portable 5G Wi-Fi ( 5.15 − 5.85 GHz ) applications. The DRA is excited by HE M 11 δ and HE M 21 δ modes. A slotted right-angle frustum-shaped (SRFS) structure of alumina material as a dielectric resonator (DR) is positioned on the ground plane of the FR4 substrate to design a DRA. Based on the designed DRA, a compact ( 2.57 λ g × 2.57 λ g , where λ g is guided wavelength and calculated at a lower cut-off frequency, 5.0 GHz , for ϵ f of 4.4 ) 4 × 4 MIMO antenna with high isolation of greater than 27.13 dB (from 5.0 to 6.1 GHz ) and 24.3 dB (from 6.1 to 6.25 GHz ) is proposed. The developed MIMO antenna's measured working frequency ranges from 5.0 to 6.25 GHz , with an impedance bandwidth, B W i of 22.22 % , peak gain, G P of 5.85 dBi and an average peak gain, G av of 5.25 dBi . The calculated MIMO antenna's diversity performance parameters, channel capacity loss ( C CL ij ) , diversity gain ( D G ij ) , envelop correlation coefficient ( E CC ij ) , mean effective gain ( M EG i ) , total active reflection coefficient ( T ARC ) , and channel capacity ( C C ) are obtained as < 0.17 bits / sec / Hz , > 9.99 dB , < 0.0301 , < − 6.06 dB , < − 12.5 dB , and < 21.6 bits / sec / Hz , respectively. The agreement between the simulation and measurement results is found to be remarkably consistent.

Advancements in MIMO Antennas for Enhanced Performance in 5G Smartphones Communication

In this review paper provides a comprehensive overview of recent advancements in multiple input multiple output (MIMO) antenna designs for 5G smartphones. There are various antenna configurations that are discussed along with benefit and limitations. The paper also examines key challenges such as antenna mutual coupling, isolation and the size constraints inherent in smartphones. Furthermore, the impact of MIMO antenna design on 5G smartphone performance characteristics such as gain, radiation efficiency and spatial multiplexing capability is also analyzed. Finally, future research directions and potential innovations in MIMO antenna technology for 5G smartphones are identified to address emerging requirements and opportunities in next-generation wireless communication systems. The comprehensive comparison of different MIMO antenna performance is also given.

Circularly polarized dielectric resonator based MIMO antenna for sub-6 GHz 5G cognitive radio applications

A 2-port wideband circular polarized (CP) multiple input multiple output (MIMO) dielectric resonator antenna (DRA) integrated with cognitive radio (CR) application is designed and investigated. This is a novel concept of integrating wideband CP-MIMO antenna based on dielectric resonator (DR), with CR concept. The multi-functional reconfigurable filter is designed within the feedline of the antenna making it applicable for both the operations of CR, namely, underlay and interweave. Rogers RT Duroid 5880 is used as the substrate for the designed CP-MIMO antenna. The antenna shows wide Axial Ratio (AR) bandwidth of 48.14% (2.2–3.50 GHz) and an overlapping bandwidth of 41.85% (2.37–3.50 GHz). The DR based MIMO antenna shows sensing range of 2.37–3.66 GHz. For the interweave operation, the designed CP-MIMO antenna shows narrowband frequency reconfigurability from 2.45–2.83 GHz. For the underlay case, the designed antenna shows band notch tunability between 3.23–3.62 GHz. The proposed antenna can be used effectively in sub-6 GHz band of the 5G communication systems.

FSS inspired two port CP MIMO antenna with enhanced gain for X-band applications

In this work, a dual-port circularly polarized (CP) Multiple Input Multiple Output (MIMO) antenna equipped with frequency selective surface (FSS) for X-band applications is designed and analyzed. The antenna system aims to enhance gain, a critical parameter like isolation radiation pattern, etc. In wireless communication systems working in the X-band frequency range. The present MIMO antenna consists of two parts that provide coverage for the whole frequency band of 7.6–11.6 GHz, specifically for X-band communication applications. As a decoupled network, the meander line architecture greatly improves isolation. The MIMO antenna's measurements include 25 × 30 × 1 mm3. To improve the antenna's peak gain even further, a FSS is placed below the present MIMO antenna at 10.5 mm. The whole volume of the FSS-inspired composite structure is 50 × 60 × 11.6 mm3. By correctly incorporating the FSS array with the antenna's structure and utilizing its frequency-selective properties, gain improvement can be attained. Without FSS, the antenna's gain is 4.8 dBi and it is enhanced by 21 % and the maximum value of gain is 15 dBi in the desired frequency spectrum. The efficiency of the proposed FSS-inspired structure is >84.2% in the operating frequency band. To evaluate the MIMO performance of the current antenna, several attributes are evaluated. On the evaluation, it is found that the present MIMO antenna has an envelope correlation coefficient (ECC) < 0.004, a diversity gain (DG) over 9.99, measured mean effective gain (MEG) below 3 dB, and CCL of less than 0.4 bits/s/Hz throughout the resonant frequency spectrum. Through modeling and experimental testing, the current MIMO antenna model is created and verified.

Fractal Engineering Integration in Antenna Arrays: A Comparative-review for Advanced Transceiver Systems with 5G/IoT Connectivity

The growing demand for space-efficient antennas compatible with portable electronic gadgets inspired the integration of recursively iterated fractal geometries (characterized by self-similarity, space-filling, and multiband/wideband capabilities) in antenna designs. Therefore, this article conducts an extensive survey on fractal-based single-port and multi-port patch antenna designs with multiband and ultrawideband characteristics for their implementation in 5G/IoT (Internet of Things) devices. The survey begins with a basic overview of fractal geometries and the iterated function system (IFS) technique employed for their generation. Further, it highlights the limitation of multipath fading prevalent in single-port antenna arrays that can be overcome by adopting multiple-input multiple-output (MIMO) technology. The MIMO antenna systems are vital for 5G networks to enhance data transmission rate, network capacity, and system reliability. Apart from these admirable attributes, the closely packed antenna elements in the MIMO configuration result in a severe mutual coupling. To address this limitation, various isolation enhancement techniques developed by distinguished researchers are thoroughly discussed in this article, detailing their merits and demerits. At last, this article portrays diverse band-notch structures integrated into the antenna designs to eradicate the existing interfering narrow bands in the ultrawideband (UWB) spectrum. The underlying reason for conducting this survey is to aid antenna designers and academicians with a thorough knowledge of distinct fractal geometries, various isolation improvement approaches, and band-notch techniques on a single platform, desired for designing 5G/IoT-based antenna systems.

Compact design of MIMO antenna with split ring resonators for UWB applications

In recent times, the Multiple-Input Multiple-Output (MIMO) system has played a vital role in wireless communication. MIMO antenna uses multiple antennas on both the sides of the transmitter and receiver. Mutual coupling occurs between two antenna elements to reduce the performance. The passage of current in the same direction on both neighbouring sides of the antennas increases the rate of mutual coupling. To decrease the mutual coupling, Split Ring Resonators (SRR) are located on the MIMO antenna. In this research paper, a MIMO antenna with SRR for Ultra Wide Band (UWB) applications with different frequency notches is proposed. Also, bandwidth and isolation are considered essential metrics for MIMO antennas. In the proposed 4 × 4 MIMO antenna design, SRR is located at the antenna's two sides, and the defected ground structure is on the bottom portion with a permittivity of 4.4 (FR4 substrate). The defected ground structure is proposed with stubs to enhance the characteristics of bandwidth and create notch bands in the frequency range of 3.1 GHz to 10.6 GHz. Placing SRRs adjacent to the feed line enhances the gain performance. The experimental results show that the ECC of the proposed antenna is less than 0.25, DG is higher than 9.8 dB, and the peak realized gain for 9.38 GHz is 11.3 dB, which is more reliable than other antenna designs. Therefore, experimental outcomes of the proposed antenna design enhance the applicability of band notching for wideband communication.

Trust region framework-based design of sub-6 GHz m-MIMO antenna and evaluation of SAR

PurposeCurrently, massive multiple-input multiple-output (m-MIMO) antennas are typically designed using complex trial-and-error methods. The purpose of this study is to determine an effective optimization method to achieve more efficient antenna design processes.Design/methodology/approachThis paper presents the design stages of a m-MIMO antenna array compatible with 5G smartphones operating in long term evolution (LTE) bands 42, 43 and 46, based on a specific algorithm. Each antenna element in the designed 10-port m-MIMO antenna array is intended to perfectly cover the three specified LTE bands. The optimization methods used for this purpose include the Nelder–Mead simplex algorithm, covariance matrix adaptation evolution strategy, particle swarm optimization and trust region framework (TRF).FindingsAmong the primary optimization algorithms, the TRF algorithm met the defined objectives most effectively. The achieved antenna efficiency values exceeded 60.81% in the low band and 68.39% in the high band, along with perfect coverage of the desired bands, demonstrating the success of the design with the TRF algorithm. In addition, the potential electromagnetic field exposure caused by the designed m-MIMO antenna array is elaborated upon in detail using computational human models through specific absorption rate analysis.Originality/valueThe comparison of four different algorithms (two local and two global) for use in the design of a 10-element m-MIMO antenna array with a complex structural configuration and the success of the design implemented with the selected algorithm distinguish this study from others.

Wireless powered NOMA-based cognitive radio for 6G networks

The need for physically charging mobile devices is anticipated to become a thing of the past in the not-too-distant future. In this paper, a novel approach for wireless-powered mobile devices is presented, which is based on non-orthogonal multiple access (NOMA) and multi-user multiple-input multiple-output (MU-MIMO) antenna systems. The proposed method is specifically designed for use in a cognitive underlay radio (CR) scenario, where the primary network requires a certain quality of service (QoS). Meanwhile, secondary network users can download their data using the same spectrum. The main objective of this paper is to maximize the sum rate of the secondary network. We have optimized a joint beamforming vector for both primary and secondary networks and a time-switching coefficient for energy harvesting and information transfer to achieve this objective. The initial problem formulation was non-convex, requiring the implementation of various techniques to ensure an efficient and low-complexity algorithm. To this end, we employed semi-definite programming, successive convex approximation, and alternating optimization. The proposed NOMA-based solution outperforms the TDMA-based benchmark scheme regarding sum data rate, specifically in the low transmit power region.

Pattern Diversity Based Four-Element Dual-band MIMO Patch Antenna for 5G mmWave Communication Networks

This study presents a planar dual-band multiple-input multiple-output (MIMO) antenna design for the prospective fifth-generation (5G) frequency bands of 28 and 38 GHz. The antenna element is designed by utilizing a rectangular patch with an offset microstrip feeding technique. A dual-band response is achieved by placing semi-circular slots on each side of the patch element. To tune the frequency response and improve impedance matching, vertical rectangular slits are etched in the rectangular patch and the ground plane, respectively. The results show that the single antenna element offers an impedance bandwidth of 2.52 GHz (26.32–28.84 GHz) and 7.5 GHz (34–41.5 GHz). In addition, a MIMO configuration based on pattern diversity using four antenna elements is designed and fabricated. The designed MIMO configuration achieves an impedance bandwidth of 3 GHz (27–30 GHz) and 5.46 GHz (35.54–41 GHz) at operating bands of 28 and 38 GHz. The peak realized gain for the single element at 28 and 38 GHz is noted to be 7.4 dBi and 7.5 dBi, respectively. Furthermore, the polarization diversity configuration illustrates an isolation of > 15 dB and > 25 dB for the 28 and 38 GHz frequency bands, respectively. Moreover, the MIMO configuration attains appropriate values for the envelope correlation coefficient (ECC) and diversity gain (DG), Total Active Reflection Co-efficient (TARC), Channel Capacity Loss (CCL) and Mean Effective Gain (MEG) for the operating frequency bands. The proposed MIMO system based on results seems to be potential choice for mmwave Ka Band Applications.

Circumferential slots based decoupled wideband MIMO antenna for 5G and sub-6 GHz applications

This paper investigates a small size 2 × 2 wideband multiple input multiple output (MIMO) antenna covering frequency band of 2.61 to 5.52 GHz. The antenna structure consists of elliptical ring patch with multiple circumferential slots. The edge-to-edge separation between the patches are kept 3.6 mm with volumetric dimensions of 30 × 46 × 1.6 mm3. The narrow slits are etched in the tapered ground plane to obtain the wideband characteristics. The electromagnetic coupling is improved more than 16 dB by employing the neutralization technique. The measured average gain and radiation efficiency of the proposed antenna are above 2.61dBi and 83.54%, respectively across the operating band. In addition to that, the important MIMO diversity parameters are investigated. The group delay and signal analysis in different orientations are also studied to ensure the quality performance of the antenna. The proposed MIMO antenna is simulated using CST microwave studio and further validated with the measurements. In addition to that, the parallel and orthogonal configuration of 4 × 4 MIMO antennas are analyzed by extending the proposed 2 × 2 MIMO design. The 4-port MIMO antennas exhibit the operating frequency bands varying from 2.80 to 5.58 GHz and 3.4 to 5.52 GHz, respectively for parallel and orthogonal MIMO configurations. The diversity parameters of 4-port MIMO antennas are calculated and compared with the measured results to verify its practical applications. Finaly, the SAR analysis of the antenna is presented at 3.08 and 5.20 GHz for 1/10 g tissues and are found 0.111/0.106 and 0.079/0.063 W K−1g−1, respectively. The proposed MIMO antenna designs are suitable for modern high-speed communication for 5G and sub-6 GHz frequency bands.

A high isolation wideband palm tree-shaped printed 4 × 4 MIMO antenna for 5G mm-waves applications

A high-isolation wideband MIMO (Multiple-Input Multiple-Output) antenna, shaped like a palm tree, is designed for 5G wireless communication purposes. The propounded MIMO antenna is formulated on an FR4 substrate, featuring a quartet of ports and adhering to a precise dimension of 45 × 50 × 0.8 mm3. A detailed analysis of the proposed high isolation wideband palm tree shaped MIMO antenna, considering its bandwidth, gain, isolation, radiation patterns, and diversity performance metrics such as diversity gain, channel capacity loss, mean effective gain, and total active reflection coefficient, is presented. The results obtained from simulations and measurements demonstrate good agreement, indicating the antenna’s effectiveness for intended applications. Indeed, an extensive bandwidth covering a range of 11.6 GHz from 23.4 GHz to 35 GHz is achieved by demonstrating superb reflection coefficient. Additionally, the design reports remarkable isolation and a peak gain of 12.4 dB, indicating its ability to enhance signal strength. One of the most notable features of this MIMO antenna is its coverage of multiple 5G bands, making it ideal for use in various geographical regions, including the USA and Canada (27.5–28.35 GHz, 37.0–37.6 GHz, and 37.6–40.0 GHz), China (24.75–27.5 GHz), Korea (28–39 GHz), Japan (27–29.5 GHz) and Sweden (26 GHz).

A Dual-Band 8-Antenna Array Design for 5G/WiFi 5 Metal-Frame Smartphone Applications.

This paper presents a dual-band 8-port multiple-input multiple-output (MIMO) antenna specifically designed for fifth-generation (5G) smartphones, featuring two open-slot metal frames. To enhance impedance matching and improve isolation between adjacent antenna elements, each antenna element employed a coupling feed. All simulation results in this paper come from Ansys HFSS. The operational frequency bands of the proposed antenna spanned 3.36-4.2 GHz for the lower band and 4.37-5.95 GHz for the higher band, covering 5G New Radio (NR) bands N78 (3.4-3.6 GHz) and N79 (4.4-4.9 GHz), as well as WiFi 5 (5.15-5.85 GHz). Notably, the antenna demonstrated outstanding isolation exceeding 16.5 dB within the specified operating bands. The exceptional performance positions the proposed antenna as a promising candidate for integration into 5G metal-frame smartphones.

DESIGN OF HIGHLY ISOLATED UWB MIMO ANTENNA USING STUBS BETWEEN GROUND PLANES

This study introduces an in-depth analysis and evaluation of a novel High-Isolation Ultra-Wideband (UWB) Multiple Input Multiple Output (MIMO)antenna design featuring the integration of Stubs between ground planes.The objective is to develop an antenna system capable of achieving high isolation between closely spaced antenna elements for MIMO applications while maintaining a wide operating bandwidth. The proposed antenna is composed of four slot antenna elements with a common rhombic slot, each fed by a microstrip-fed line to greatly reduce the overall size of the antenna.It has a compact size of (34 x 34 x 1.6 mm3).The wide frequency range of Ultra-wide band lies in the range of 3.1 to 10.6 GHz and wide channel bandwidths of 500 MHz.The combination of ultra-wideband multiple-input and multiple-output(UWB MIMO) technology has high transmission rate,good communication quality and large channel capacity.Investigation will be done with respect to correlation parameter coefficients,radiation characteristics,efficiency,realized gain and the active reflection coefficient. In essence,the Highly Isolated MIMO Antenna marks a significant stride in antenna technology and in the field of wireless communication.CST(Computer Simulation Technology) is used to design the proposed antenna. Keywords-Antenna,Isolation,UWB,MIMO,Stubs,S-Parameter Results.