Multiple-input Multiple-output Configuration Research Articles

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.

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.

Wideband MIMO configuration with mutual coupling reduction and better isolation using the combination of electric field LC resonator and Swastik resembled structure

This work explains the design and development of a small, wide-ranging antenna for millimeter wave (mm-Wave) and 5G technology and their applications, along with the configuration to set up as a multiple-input multiple-output (MIMO) system. Rogers RT/duroid 5880 substrate material, which has a height of 1.575 mm, is used for fabricating the antenna. It possesses a compact overall size of 36 × 36 mm2. The design process began with the creation of a octagonal conventional mm-wave microstrip antenna. Subsequently, the impedance bandwidth was enhanced by incorporating the slots of rectangular shape on either parallel edges to the patch feed enabling it to perform over a larger bandwidth ranging between 25 GHz to 32 GHz. Moreover, a new metasurface and a structure shaped like a swastika are positioned between the 2 × 2 arrangement to minimize mutual coupling. The suggested MIMO antenna provides a wide frequency range, significant gain, minimal interference between antennas, and a low correlation between signal envelopes while also achieving a high level of diversity gain. Furthermore, the proposed study has been compared to similar works to demonstrate the significance of the proposed research.

SMALL-SCALE MIMO ANTENNA WITH HIGH ISOLATION FOR 5G COMMUNICATION

This manuscript describes two- and three-element small-scale multiple-input multiple-output (MIMO) antenna configurations for 5G communications ranging from 23.5 to 28.6 GHz. Modern device antennas have two essential features: isolation and a larger bandwidth. In this regard, firstly a single element antenna has been designed using quarter wavelength impedance transformer and semi-circular loaded patch along with defected ground structure. Furthermore, two single-element antennas are placed orthonormal to each other having quarter wavelength distance from the center of the single-element antenna. To increase the bandwidth and isolation, additionally a rectangular patch and strip isolate from ground. This structural change alters the current path, improving the impedance matching and isolation of the two-element MIMO antenna configuration. After that the three-element MIMO configuration was formed by placing two single-element antennas orthogonally at quarter wavelength from the center of the single-element antenna. The total size of two- and three-element MIMO antenna is 15 × 11 × 1.6 mm and 20 × 11 × 1.6 mm, respectively. The proposed MIMO antennas provide isolation of more than 21 dB and gain more than 25 dB throughout the working band. MIMO diversity features function reasonably well, with an envelope correlation coefficient of less than 0.002 and diversity gain of 10. Proposed antennas can be a good candidate for MIMO applications in the 5G communication frequency range 2 (FR2), 28 GHz bands.

Spectral estimation model for linear displacement and vibration monitoring with GBSAR system

In recent years, there has been a growing interest in the development of ground-based Synthetic Aperture Radars (GBSAR) for the purpose of monitoring structural displacements. GBSAR offers high-resolution monitoring over a wide area and can capture data every few minutes. However, compact high-frequency multiple input multiple output (MIMO) radars have emerged as an alternative for monitoring sub-second displacements, such as structural vibrations. MIMO radar has sub-second acquisition interval. However, it has limited cross-range resolution compared to GBSAR, and interference between antennas and presence of multiple scatterers in the scene can cause strong sidelobes in the processed data. On the other hand, GBSAR utilizes a long synthetic aperture to achieve high cross-range resolution. However, due to its longer data acquisition time compared to MIMO radar, conventional methods are insufficient for detecting scatterers’ sub-second displacements that occur during the data acquisition process. This study proposes a method to effectively monitor sub-second or sub-minute displacements using GBSAR signals. The proposed method enhances the conventional radar interferometric processes by employing spectral estimation, allowing for multi-dimensional detection of targets’ azimuth angle, linear displacement, and vibrational characteristics. Consequently, this method improves both the processing of MIMO radar data and enables high-resolution fast displacement monitoring from GBSAR signals. The paper presents the theoretical details and mathematical formulations of the proposed method for both MIMO radar and GBSAR imaging modes. To evaluate the effectiveness of the proposed method, numerical simulations and real experiments are conducted. The experimental results validate the capability of the proposed method in both GBSAR and MIMO configuration modes for high-resolution monitoring of fast linear displacements and vibrations. The results exhibit promising signal-to-noise ratio (SNR) and peak-to-sidelobe ratio (PSLR) values.

A Low-Profile Quad Element High Isolation MIMO Antenna for Enhanced Mobile Broadband Applications

A novel quad-element bio-inspired virus-shaped Multiple Input-Multiple Output (MIMO) antenna with significantly improved isolation is proposed. Each radiator is based on a modified hybrid fractal antenna with a 50 Ω feed and incorporates a chamfered defective ground structure (DGS). To enhance the impedance bandwidth and radiation characteristics of the antenna, an elliptical slot and the DGS are employed. The placement of radiating elements in an orthogonal configuration is a key aspect of achieving the proposed MIMO configuration. In many MIMO designs, one of the primary challenges is achieving adequate isolation between antenna ports. However, in this design, we address this issue effectively by incorporating a swastik-shaped decoupling plane, which significantly enhances the isolation characteristics. The 4-port MIMO antenna is constructed on a Rogers RO3003 substrate and boasts compact dimensions of 57 × 57 × 0.787 mm³. The fabricated antenna has undergone experimental validation, confirming that it covers a substantial operational bandwidth of 41.57 GHz, ranging from 2.54 to 44.1 GHz, has a fractional bandwidth of 178%, and maintains isolation levels of less than −23 dB across its entire frequency range. The antenna design has achieved optimal MIMO performance, characterized by an Envelope Correlation Coefficient (ECC) value of ≤0.05, high multiplexing efficiency, minimal Channel Capacity Loss (CCL), and omnidirectional radiation properties. Hence, this design stands as an epitome for constructing super-wideband MIMO designs. The design metrics show the potential of the proposed antenna to operate with Enhanced Mobile Broadband (eMBB) which forms an integral part of 5G applications.

Adaptive power permutation modulation: A novel transmission technique for increased spectral efficiency over fading channels

SummaryIn this study, we propose a novel transmission technique for multiple‐input multiple‐output (MIMO) systems as a partial response to ever‐growing demand for the increased spectral efficiency. The introduced scheme, called adaptive power permutation modulation (APPM), relies on the distinct power allocations on the conventionally modulated symbols to convey a certain number of additional information bits. Unlike the traditional power allocation strategies which generally aim to combat the channel fading and entail some form of channel state information (CSI) at the transmit side, APPM utilizes different power levels to convey additional information and does not necessitate any kind of CSI at the transmitter. The proposed approach is applied to two well‐known MIMO configurations, Alamouti space‐time block coding and zero‐forcing beamforming, by embracing a general frequency‐selective fading scenario under digital phase modulation. Both the modulation order and the power allocation levels on the modulated symbols are adaptively determined based on a set of additional information bits. It is shown that in addition to the conventionally modulated symbols, an extra sequence of bits can be conveyed without any significant additional complexity where equals the number of subcarriers. Also, it is demonstrated that considerable transmit power savings can be attained when compared with the standard schemes under a certain target spectral efficiency.

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.

Antenna Selection for Reconfigurable Intelligent Surfaces: A Transceiver-Agnostic Passive Beamforming Configuration

Reconfigurable intelligent surface (RIS) is capable of improving the wireless system performance by steering the reflected signal in the desired direction. One of the major challenges is that both the transceiver and RIS have to be jointly optimized, where the optimization problems have to be reformulated for different system models and scenarios. To circumvent this challenge, new low-complexity antenna selection (AS) algorithms for transceiver-agnostic RIS configuration are proposed. Given a multiple-input multiple-output (MIMO) channel, the proposed RIS-AS opts for accurately aligning the RIS both with the transmit antenna (TA) and receive antenna (RA) for the sake of maximizing the MIMO channel’s overall output power. The proposed RIS-AS only has to configure the RIS alone, i.e. without iterations with the transceiver optimization. As a result, the proposed RIS-AS has the compelling benefit that they are generically applicable, regardless of the specific transceiver architecture. Our simulation results confirm that the proposed RIS-AS is capable of supporting any MIMO configuration, regardless of their closed/open-loop, single-/full-RF and multiplexing-/diversity-oriented setups.

High isolation frequency-reconfigurable UWB-MIMO antenna with on-demand WiMAX band elimination

Abstract In this article, a planar dual-element frequency reconfigurable multiple-input multiple-output (MIMO) antenna for ultra-wideband (UWB) applications is studied. The frequency band can be switched between UWB operation and single band rejected UWB performance using a pair of PIN diodes in the MIMO configuration. The presented antenna is comprised of two similar slotted circular radiators, having tapered microstrip feedlines and separate partial ground planes. An RT/Duroid 5880 substrate with size 54 × 54 mm2 is used for the design purpose. Rotational symmetry between the radiators and diagonally oriented t-shaped decoupling structure behind the substrate have been utilized for high isolation purpose. The designed MIMO antenna exhibits UWB performance in mode 1. In other mode, the antenna operates in the frequency range 2.46–10.44 GHz with Worldwide Interoperability for Microwave Access (WiMAX) band rejection. Thus, the MIMO antenna exhibits on-demand single band rejection behavior depending on the switching conditions of the diodes. The measured isolation is greater than −20 dB in both the modes. The presented MIMO configuration possesses compact and planar geometry with high gain, good isolation, ultrawideband performance with reconfigurable band elimination, high efficiency and efficient diversity performance parameters. The suggested antenna is a good choice to be utilized for portable UWB MIMO applications.

A planar UWB-MIMO antenna with high isolation and reconfigurable single band-elimination characteristics

A compact ultra-wideband (UWB) triple mode frequency reconfigurable multiple-input multiple-output (MIMO) antenna with electronically controllable single band elimination properties is presented in this work. The reported antenna comprises of two rotationally symmetric identical modified circular radiators each having tapered microstrip feed lines and separate partial defected ground structures (DGS). The slotted radiating patches consist of C-shaped parasitic strips placed at their centers. Two PIN diode switches were utilized to join and detach the C-shaped strip and slotted circular radiator, and thus total four PIN diodes are employed in the dual-port MIMO configuration to achieve switchable operation between UWB and single band-notched UWB characteristics. The recommended antenna possesses ultrawide bandwidth with Snn ≤ −10 dB except at the rejected bands and attains isolation better than −21 dB in all reconfigurable modes. The proposed MIMO antenna shows good diversity behavior which has been proved through the study of various parameters, such as envelope correlation coefficient (ECC), CCL and diversity gain with values fulfilling the acceptable standard for practical usage. High diversity gain and ECC value below 0.0006 are obtained for all the modes. The suggested antenna structure is ideally suited for ultrawideband MIMO systems with on-demand suppression of WiMAX or WLAN signals.

Performance Evaluation of Photonics-Based Coherent MIMO Radar Systems for Maritime Surveillance

Multiple-input multiple-output (MIMO) radars offer significant advantages over conventional standalone radars in terms of target detection and localization capabilities. However, to fully exploit their potential, such systems require excellent time and phase synchronization among the central unit and the radar heads. Only recently, thanks to microwave photonics (MWP) techniques, it has been possible to develop the first coherent MIMO radar demonstrators. In this paper, a simulation tool in MATLAB programming language is proposed to model coherent MIMO radars based on MWP techniques in maritime surveillance applications. Moreover, a novel approach for estimating the radar cross section of extended maritime targets is presented. The system performance in co-located and distributed MIMO configuration, as well as in single- and multi-band operations, is evaluated by means of relevant key performance indicators (KPIs). Simulations are carried out in two close-to-reality scenarios. In the first, a co-located MIMO radar is mounted on top of a patrolling vessel. In the second, a distributed MIMO radar is deployed inside a port. The proposed KPIs are analyzed in terms of both geometric and frequency diversities of the system, laying the foundations for general system optimization criteria valid in any given surveillance application.

MIMO 5G Smartphone Antenna with Tri-Band and Decoupled Elements.

In this article, a miniaturized antenna is proposed for 4G/5G multiple input, multiple output (MIMO) applications for smartphones. The proposed antenna is composed of an inverted L-shaped antenna with decoupled elements to cover 4G (2000-2600 MHz), and a planar inverted-F antenna (PIFA) with a J-slot to cover 5G (3400-3600 MHz and 4800-5000 MHz). Furthermore, to achieve the purposes of miniaturization and decoupling, the structure adopts a feeding stub, shorting stub, and outstanding floor, additionally adding the slot to the PIFA, to generate additional frequency bands. Due to the advantages such as multiband operation, MIMO configuration for 5G communications, high isolation, and a compact structure, the proposed antenna design is attractive for 4G/5G smartphones. The antenna array is printed on an FR4 dielectric board, measuring 140 × 70 × 0.8 mm3, with the 4G antenna located on a top 15 mm-long headroom.

A Car Logo Design-Inspired CPW-Fed Semitransparent Antenna for Vehicular Applications

In this paper, a quad-port multiple-input multiple-output (MIMO) semitransparent antenna is designed for automotive applications. The transparent soda lime glass substrate is used in the prototype antenna for windshield applications, and the radiator is nontransparent copper metal. The unit cell radiator of the MIMO antenna is similar to the “NISSAN automobile-like” logo. The proposed MIMO antenna has a −10 dB impedance bandwidth of 3.4 to 11 GHz. The edge-to-edge distance between the elements in the MIMO configuration is 6 mm. The antenna elements are perpendicularly oriented to offer dual (horizontal and vertical) polarization, which aids in providing better isolation and good signal reception in all directions. The isolation between the resonating elements is greater than 15 dB without the use of any decoupling structure. The diversity metrics are examined in order to gain a better understanding of the MIMO antenna performance. The envelope correlation coefficient (ECC) is less than 0.01, diversity gain (DG) is greater than 9.98 dB, and the total active reflection coefficient (TARC) and channel capacity loss (CCL) are less than −10 dB and 0.07 bits/s/Hz, respectively. The quad-port MIMO antenna offers transparency of 52.26% over the entire area. The proposed antenna could be suitable for automotive applications such as intelligent transportation systems (ITS), vehicular communications, and the automatic vehicle identifier (AVI).

In-band full-duplex MIMO PLC systems for relaying networks

In Power Line Communications (PLC), there are regulatory masks that restrict the transmit power spectral density for electromagnetic compatibility reasons, which creates coverage issues despite the not too long distances. Hence, PLC networks often employ repeaters/relays, especially in smart grid neighborhood area networks. Even in broadband indoor PLC systems that offer a notable data rate, relaying may pave the way to new applications like being the backbone for wireless technologies in a cost-effective manner to support the Internet-of-things paradigm. In this paper, we study Multiple-Input Multiple-Output (MIMO) PLC systems that incorporate in-band full-duplex functionality in relaying networks. We present several MIMO configurations that allow end-to-end half-duplex or full-duplex operations and analyze the achievable performance with state-of-the-art PLC systems. To reach this analysis, we get channel realizations from random network layouts for indoor and outdoor scenarios. We adopt realistic MIMO channel and noise models and consider transmission techniques according to PLC standards. The concepts discussed in this work can be useful in the design of future PLC relay-aided networks for different applications that look for a coverage extension and/or throughput: smart grids with enhanced communications in outdoor scenarios, and “last meter” systems for high-speed connections everywhere in indoor ones.

A Dual Port Hybrid Super-wideband MIMO Antenna with Diminished CCL and High BDR for IoT Applications

In this work, a simple hybrid dual port skull-shaped super wideband Multiple Input Multiple Output (MIMO) antenna with improved isolation is designed and analyzed. Each antenna element consists of a skull-shaped radiator along with a rectangular notched chamfered Defective Ground Plane structure (DGS). The proposed antenna’s impedance bandwidth and radiation characteristics are improved by the triple elliptical inclined slot and DGS together. To accomplish the proposed MIMO configuration, the antenna elements are further organized in a linear arrangement. Deteriorated isolation characteristics, which are the key bottleneck for such MIMO schemes, are significantly improved in the proposed design by using a corrugated T-shaped strip decoupling plane. This 2-port MIMO antenna is placed on top of a glass epoxy FR4 substrate and has an overall dimension of 45 × 50 × 0.787 mm3 (0.20λ × 0.19λ × 0.003λ). The proposed MIMO antenna is fabricated and the experimental results are verified with the simulation results. The results indicate that the proposed antenna covers an operational bandwidth of 48.75 GHz (1.25–50 GHz) with a fractional bandwidth of 190.24% and offers an isolation of less than −20 dB throughout the frequency range of operation. The proposed MIMO has an extremely high bandwidth dimension ratio (BDR) of 5092 among the reported antennas. An optimal performance has been achieved with a lower value of Envelope Correlation Coefficient (ECC) ≤ 0.02, high multiplexing efficiency, extremely lower Channel Capacity Loss (CCL) of 0.2, and omnidirectional radiation characteristics. These design metrics show the potential of our antenna to operate for eMBB (Enhanced Mobile Broadband) applications which includes 5G, Augmented reality, and etc.

Tree-Search-Based Optimal and Suboptimal Low Complexity Detectors for Differential Space Shift Keying MIMO System

This article proposes two low complexity decoders for non coherent differential space shift keying (DSSK) multiple input multiple output (MIMO) system by representing the detection problem as a hierarchical tree structure. Such presentation enables yielding the optimal maximum likelihood (ML) performance but with a massive reduction in computational complexity. Attained reduction is accomplished through 1) utilizing the error-repetitive property of DSSK detection to reduce the number of computed error terms and 2) developing two efficient searching strategies that avoid searching the entire alphabet as in ML detectors. These searching strategies enable a trade–off between performance and complexity. Unlike existing sparse recovery (SR) decoders, which require a projection phase to ensure the closure property (i.e., only single transmit antenna is active at each particular time instant and the multiplication of a constellation matrix with another one will produce a matrix from within the set), the new algorithms, inherently, maintain the closure property of DSSK system without additional procedures. Reported results reveal that optimal ML performance is obtained with a huge reduction in complexity by proper adjustment of parameters. It is also shown that the proposed algorithm performs better than state of the art SR algorithms, and the feasibility of massive MIMO configurations with low complexity is demonstrated.

Comparison between Compressive Sensing and Non-Uniform Array for a MIMO GBSAR with Elevation Resolution: Simulations and Experimental Tests

Ground-based synthetic aperture radars (GBSAR) are popular instruments widely used for the monitoring of infrastructures. One of the main problems of ground-based interferometric radars is the elevation ambiguity. Multiple-input multiple-output (MIMO) arrays could solve this problem. This work proposes a study on possible MIMO configurations to achieve elevation resolution in ground-based radar measurements. Specifically, two array configurations are compared: a random sparse array suitable for the compressive sensing technique, and a non-uniform array. The two solutions are compared by means of simulations and experimental tests. An ad hoc system has been developed to jointly test the two configurations, and results obtained in a controlled and real urban scenario are shown. It is found that both systems are able to solve elevation ambiguity. The non-uniform array seems to achieve good performance in a general scenario, while the CS processing can outperform the other only after optimization, depending on the specific scenario and application.

Isolation Improvement of Parasitic Element-Loaded Dual-Band MIMO Antenna for Mm-Wave Applications.

A dual-band, compact, high-gain, simple geometry, wideband antenna for 5G millimeter-wave applications at 28 and 38 GHz is proposed in this paper. Initially, an antenna operating over dual bands of 28 and 38 GHz was designed. Later, a four-port Multiple Input Multiple Output (MIMO) antenna was developed for the same dual-band applications for high data rates, low latency, and improved capacity for 5G communication devices. To bring down mutual coupling between antenna elements, a parasitic element of simple geometry was loaded between the MIMO elements. After the insertion of the parasitic element, the isolation of the antenna improved by 25 dB. The suggested creation was designed using a Rogers/Duroid RT-5870 laminate with a thickness of 0.79 mm. The single element proposed has an overall small size of 13 mm × 15 mm, while the MIMO configuration of the proposed work has a miniaturized size of 28 mm × 28 mm. The parasitic element-loaded MIMO antenna offers a high gain of 9.5 and 11.5 dB at resonance frequencies of 28 GHz and 38 GHz, respectively. Various MIMO parameters were also examined, and the results generated by the EM tool CST Studio Suite® and hardware prototype are presented. The parasitic element-loaded MIMO antenna offers an Envelop Correlation Coefficient (ECC) &lt; 0.001 and Channel Capacity Loss (CCL) &lt; 0.01 bps/Hz, which are quite good values. Moreover, a comparison with existing work in the literature is given to show the superiority of the MIMO antenna. The suggested MIMO antenna provides good results and is regarded as a solid candidate for future 5G applications according to the comparison with the state of the art, results, and discussion.

Performance analysis of regression‐based machine learning models towards intelligent selection of MIMO configurations

AbstractFifth Generation (5G) fosters the integration of several technologies for achieving the requirements of rapid and reliable communications. Multiple Input Multiple Output (MIMO) is one such technology implemented in communication systems with the aim of delivering better services to users. Machine Learning (ML) technologies are also being used alongside MIMO since they can aid with the selection of the most appropriate MIMO configuration based on antenna, data, and channel parameters. These parameters can be further used as input features to the models for obtaining the best data rate and throughput. In this paper, three different MIMO configurations, 2 × 2, 3 × 3, and 4 × 4 MIMO using directional and omnidirectional antennas have been simulated. Power propagation from each antenna, MIMO power, channel capacity, data rate, and throughput have been used as response variables. The data obtained from these simulations are used to train regression models for prediction of new data. Frankfurt city is used as scenario in this simulation and the models are analyzed based on the root mean squared error (RMSE) values obtained. The results demonstrate that the interactions linear regression, fine tree and medium tree models provide the lowest RMSE values when predicting the variables for different MIMO configurations using directional and omnidirectional antenna.