Proposed Multiple-input Multiple-output System Research Articles

Triple band self-decoupled MIMO antenna pair for 5G communication

A two port multiple input multiple output (MIMO) antenna with self-isolation is proposed for the application of fifth generation (5G) mobile phones. In this antenna, feeding ports that are inherently isolated across a bandwidth without the need for extra decoupling components directly excite the MIMO antenna. An approach involving the creation of common and differential modes utilizes a mode-cancellation technique to comprehensively understand the self-decoupling mechanism on a physical level. The proposed self-decoupled antenna pair exhibits about 22 dB isolation across the triple band 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz, respectively. According to the experimental findings, the proposed MIMO system may offer better than 22 dB isolation across all ports and a respectable level of overall gain 1.9 dBi, 3.77 dBi and 2.9 dBi across 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz. A suggested design method, with its advantages of self-decoupling, simple structure, high efficiency and triple band demonstrates amazing upcoming 5G highly integrated MIMO antennas for 5G devices.

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.

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.

A Four Element mm-Wave MIMO Antenna System with Wide-Band and High Isolation Characteristics for 5G Applications.

In this article, we propose a light weight, low profile Multiple Input Multiple Output (MIMO) antenna system for compact 5th Generation (5G) mmwave devices. Using a RO5880 substrate that is incredibly thin, the suggested antenna is made up of circular rings stacked vertically and horizontally on top of one another. The single element antenna board has dimensions of 12 × 12 × 0.254 mm3 while the size of the radiating element is 6 × 2 × 0.254 mm3 (0.56λ0 × 0.19λ0 × 0.02λ0). The proposed antenna showed dual band characteristics. The first resonance showed a bandwidth of 10 GHz with a starting frequency of 23 GHz to an ending frequency point of 33 GHz followed by a second resonance bandwidth of 3.25 GHz ranging from 37.75 to 41 GHz, respectively. The proposed antenna is transformed into a four element Linear array system with size of 48 × 12 × 0.254 mm3 (4.48λ0 × 1.12λ0 × 0.02λ0). The isolation levels at both resonance bands were noted to be >20 dB which shows high levels of isolation among radiating elements. The MIMO parameters such as Envelope Correlation Co-efficient (ECC), Mean Effective Gain (MEG) and Diversity Gain (DG) were derived and were found to be in satisfactory limits. The proposed MIMO system model is fabricated and through validation and testing of the prototype, the results were found to be in good agreement with simulations.

Design of compact two‐port dual‐band dual‐polarized MIMO antenna for CBRS and WLAN sub‐6‐GHz applications

SummaryThis communication presents a compact field de‐correlation lines integrated dual band with dual‐polarized (LP & CP) multiple‐input multiple‐output (MIMO) antenna for the fifth generation (5G) sub‐6‐GHz wireless communication systems. Dual working bandwidths, smaller interelement gaps, and superior isolation within the MIMO components are the distinguishing characteristics that give the proposed MIMO system an aspect of novelty. The modeled MIMO antenna has compact configurations of 20 × 21 × 0.8 mm3. The unit cell consists of a microstrip feed line with optimized rectangular slots branches etched from the radiated patch. The MIMO module is generated by the antiparallel replication of a single unit cell. To enhance the isolation, two rectangular slots are incorporated on the patch between the unit elements, which act as field de‐correlation lines. The MIMO identity is supported by diversity performance calculations in terms of ECC, DG, and TARC. Simulated and measured counterparts are found in the agreement.

Dual-Band Antenna Pair With High Isolation Using Multiple Orthogonal Modes for 5G Smartphones

This communication presents a novel decoupling method to design a dual-band closely arranged multiple-input multiple-output (MIMO) antenna pair with high isolation for fifth-generation (5G) smartphones. By combining a bent loop and a T-shaped monopole into a compact space with a miniaturized size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$21.8\times $ </tex-math></inline-formula> 7 mm2, multiple orthogonal in-phase modes and out-of-phase modes are excited at two different bands, respectively, to decrease the mutual coupling. Although the bent loop is closely spaced to the T-shaped monopole, the proposed antenna pair exhibits high isolation of more than 24 dB in dual bands without any decoupling structures. An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO system operating at 3.3–3.6 GHz and 4.4–5.0 GHz is developed by arranging four such antenna pairs. The isolation is more than 12.8 dB, the envelope correlation coefficients (ECCs) are lower than 0.18, and the efficiencies are better than 71% and 68% in two bands for the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO system. The proposed MIMO system features dual-band operation, compact structure, and excellent isolation, which provides a promising solution for the 5G smartphone antenna design.

Gain and isolation enhancement of a wideband MIMO antenna using metasurface for 5G sub-6 GHz communication systems

This work proposes a compact metasurface (MS)-integrated wideband multiple-input multiple-output (MIMO) antenna for fifth generation (5G) sub-6 GHz wireless communication systems. The perceptible novelty of the proposed MIMO system is its wide operating bandwidth, high gain, lower interelement gap, and excellent isolation within the MIMO components. The radiating patch of the antenna is truncated diagonally with a partially ground plane, and a metasurface has been employed for enhancing the antenna performance. The suggested MS integrated single antenna prototype has a miniature dimension of 0.58λ × 0.58λ × 0.02λ. The simulated and measured findings demonstrate a wideband characteristic starting from 3.11 to 7.67 GHz including a high realized gain of 8 dBi. The four-element MIMO system has been designed by rendering each single antenna orthogonally to one another while retaining compact size and wideband properties between 3.2 and 7.6 GHz. The suggested MIMO prototype has been designed and fabricated on a low loss Rogers RT5880 substrate with a miniature dimension of 1.05λ × 1.05λ × 0.02λ and its performance is evaluated using a suggested 10 × 10 array of a square enclosed circular split ring resonators within the same substrate material. The inclusion of the proposed metasurface with a backplane significantly reduces antenna backward radiation and manipulates the electromagnetic field, thus improving the bandwidth, gain and isolation of MIMO components. The suggested 4-port MIMO antenna offers a high realized gain of 8.3 dBi compared to existing MIMO antennas with an excellent average total efficiency of 82% in the 5G sub-6 GHz spectrum and is in good accordance with measured results. Furthermore, the developed MIMO antenna exhibits outstanding diversity characteristics in respect of envelope correlation coefficient (ECC) less than 0.004, diversity gain (DG) close to 10 dB (> 9.98 dB) and high isolation between MIMO components (> 15.5 dB). Therefore, the proposed MS-inspired MIMO antenna substantiates its applicability for 5G sub-6 GHz communication networks.

Human Activity Signatures Captured under Different Directions Using SISO and MIMO Radar Systems

In this paper, we highlight and resolve the shortcomings of single-input single-output (SISO) millimeter wave (mm-Wave) radar systems for human activity recognition (HAR). A 2×2 distributed multiple-input multiple-output (MIMO) radar framework is presented to capture human activity signatures under realistic conditions in indoor environments. We propose to distribute the two pairs of collocated transmitter–receiver antennas in order to illuminate the indoor environment from different perspectives. For the proposed MIMO system, we measure the time-variant (TV) radial velocity distribution and TV mean radial velocity to observe the signatures of human activities. We deploy the Ancortek SDR-KIT 2400T2R4 mm-Wave radar in a SISO as well as a 2×2 distributed MIMO configuration. We corroborate the limitations of SISO configurations by recording real human activities in different directions. It is shown that, unlike the SISO radar configuration, the proposed MIMO configuration has the ability to obtain superior human activity signatures for all directions. To signify the importance of the proposed 2×2 MIMO radar system, we compared the performance of a SISO radar-based passive step counter with a distributed MIMO radar-based passive step counter. As the proposed 2×2 MIMO radar system is able to detect human activity in all directions, it fills a research gap of radio frequency (RF)-based HAR systems.

H-Shaped Eight-Element Dual-Band MIMO Antenna for Sub-6 GHz 5G Smartphone Applications

The design of an eight-element H-shaped dual-band multiple-input multiple-output (MIMO) antenna system for sub-6 GHz fifth-generation (5G) smartphone applications is presented in this work. The radiating elements are designed on the side edge frame of the smartphone, placed on both sides of the main printed circuit board (PCB). Each side edge consists of four radiating elements, which ensures low mutual coupling between antenna elements. The total size of the main PCB is 150&#x00D7;75 mm², while the size of the side edge frame is 150&#x00D7;7 mm². A single antenna consists of an H-shaped radiating element fed using a 50&#x03A9; microstrip feeding line designed on the main board of the smartphone. The results show that, according to -6 dB impedance bandwidth criteria, the designed MIMO antenna radiates at two different frequency ranges within the allocated FCC 5G spectrums, i.e., 3.1-3.78 GHz and 5.43-6.21 GHz with 680 MHz and 780 MHz bandwidths, respectively. It is also observed that the antenna elements are able to provide spatial and pattern diversity for both the frequency bands. Furthermore, an isolation of &#x003E;12 dB is observed between any two given radiating elements. Various MIMO key performance parameters are evaluated, such as channel capacity (CC), envelope correlation coefficient (ECC), and diversity gain (DG). A prototype is fabricated and measured, and it is found that the measured and simulated results are in good agreement. Based on performance attributes, it can be said that the proposed MIMO system may find its application in 5G communication systems.

Mutual Coupling Reduction of a Circularly Polarized MIMO Antenna Using Parasitic Elements and DGS for V2X Communications

In this article, a 4-port circularly polarized (CP) multiple-input multiple-output (MIMO) antenna at 5.9 GHz is presented for the vehicle to everything (V2X) communications. A novel hybrid decoupling structure consisting of circular ring parasites and defected ground structure (DGS) is used to reduce the mutual coupling between the MIMO elements. The circular ring parasites are incorporated between the antennas to reduce the mutual coupling between perpendicular antennas. Whereas, the DGS significantly reduces the mutual coupling between adjacent antennas. These circular ring parasites and DGS affect the electromagnetic field distribution and consequently reduce the mutual coupling. The effectiveness of the decoupling structure is explained through transmission coefficient and surface current distribution. The simulated and measured results show that the proposed MIMO antenna provides overlapping S11 (&#x2013;10 dB) and axial ratio (3-dB) bandwidth of 2.04% (5.82 &#x2013; 5.94 GHz) with a peak gain of 7.68 dBic. Moreover, the fabricated MIMO antenna offers excellent diversity performance, isolation between antenna elements is very high (&#x003E;34dB), envelope correlation coefficient (ECC) is lower than 0.001, and diversity gain is 9.99 dB, very close to the ideal value of 10 dB. Furthermore, the link budget for the proposed MIMO system is calculated to check the suitability for V2X communications which shows that the antenna can communicate between them over a distance of 1.5 kilometers with a 21 dBm of transmit power. Owing to these qualities, the proposed MIMO antenna can be an excellent choice for V2X MIMO communications.

A novel inverted elliptical frustum shaped multi-band MIMO DRA with bandwidth and isolation enhancement

This paper presents the design and development of a two element MIMO (Multiple Input Multiple Output) antenna system designed using Elliptical frustum shaped DRA (Dielectric Resonator Antenna). In the proposed MIMO system, adjacent antenna elements are separated by0.29λ0.The archetype operates in the microwave frequency range 7.96–15.67 GHz giving a maximum isolation of 37.38 dB at 11.08 GHz frequency with a wide impedance bandwidth of 52.6%. Various diversity performance parameters like Envelope Correlation Coefficient (ECC), Diversity Gain (DG) are evaluated to understand the performance of the antenna under MIMO environment. Fabricated archetype is developed and good agreement is found between the simulated and measured results.

Muli‐UWB Antenna System Design for 5G Wireless Applications with Diversity

In this paper, we propose a compact Multiple Input Multiple Output (MIMO) antenna system with high isolation for wireless applications in 5G connected devices. This MIMO antenna system with the size of 92 × 88 mm2 consists of two elliptical antennas symmetrically arranged next to each other. Two decoupling methods which are neutralization and Defected Ground Structure (DGS) are applied to ensure diversity of the proposed MIMO antenna. The single and MIMO antennas are simulated and analyzed then fabricated and measured. A good agreement between measurements and simulations is obtained. These configurations, dedicated to covering the 3.4 GHz band ‐3.8 GHz, have shown very satisfactory performances more than ‐30 dB in terms of reduction of mutual coupling between the antennas constituting our system. MIMO diversity parameters, such as Envelope Correlation (ECC), Diversity Gain (DG), and total efficiency, are also studied for each proposed MIMO system. Thus, results demonstrate that our two proposed antenna configurations are very suitable for 5G MIMO applications.

Small‐size four‐element antenna system for 2 × 2 LTE LB and 4 × 4 LTE M/HB MIMO operations in5Gmobile terminals

A small-size four-element antenna system for 2 × 2 LTE low band (LB, 698-960 MHz) and 4 × 4 LTE middle/high band (M/HB, 1710-2690 MHz) multiple-input multiple-output (MIMO) operations in 5G (fifth-generation) mobile terminals is presented. The proposed antenna system is formed by two identical tunable loop antennas and two identical coupled-fed IFA (Inverted-F Antenna) antennas. By loading a RF switch with four output states as tunable component, the proposed loop antenna can not only operate in the M/HB, but also achieve improved bandwidth coverage in the LB. Each coupled-fed IFA element operating in the M/HB with compact volume. The four antennas are placed on the both short side-edge of the mobile terminal with small ground clearance of 4.2 mm. The simulated S-parameters show that the proposed MIMO system can cover 698 to 960 MHz and 1710 to 2690 MHz with reflection coefficients less than −6 dB and isolations are all more than 12 dB. Good MIMO performances such as radiation efficiencies, envelope correlation coefficient (less than 0.4 within the entire operation bands) and channel capacity are also obtained. The effects of user's hand(s) on performances for the proposed antenna system are also discussed. This four-element antenna system prototype is fabricated and measured.

Compact wideband MIMO mobile‐antenna system design using mode‐based decoupling techniques

This work focuses on designing small mobile antennas and their multiple-input multiple-output (MIMO) applications. In this study, it was investigated that small mobile antennas can obtain high radiation performance only when a tight coupling with the ground plane is generated through ground-mode tuning (GMT) of the ground plane. Furthermore, a novel mode-based decoupling concept is presented for their MIMO applications, based on a four-port network and by considering the ground-mode effect. Consequently, the proposed mode-based decouplers can effectively sustain high radiation performance and improve the isolation while providing low correlation by generating diagonally directed radiation patterns. In the proposed MIMO system, both GMT structures and mode-based decouplers are implemented utilizing the metal rims around the ground plane, thereby occupying very compact clearance, and the measured MIMO antennas fully covered 0.69 to 1 GHz band with high isolation up to 20 dB and low envelope correlation coefficient (ECC) value below 0.5, sufficiently applicable in mobile devices.

TAS WITH QAM-M (M=2, 3, 4, 5, 6) FOR MIMO COMMUNICATION SYSTEM

In this paper we study Orthogonal-Space-Ttime Block-Coded (OSTBC) Multiple-Input Multiple Output (MIMO) systems employing Transmit Antenna Selection (TAS) with frobenius norm as a selection criterion and compares the BER performance for QAM with order 2, 3, 4, 5 and 6. The minimum BER for the proposed MIMO system is of about 7.50x10 -05 at 14dB SNR, 1.67x10 05 at 20dB SNR, 0.225x10 -03 at 20dB SNR, 0.166x10 -02 at 20dB SNR, 0.84x10 -02 at 20dB SNR, for 4QAM, 8QAM, 16QAM, 32QAM and 64QAM respectively.

IJIREEICE - Electrical, Electronics, Instrumentation and Control

A compact design of two element Multiple Input MultipleOutput (MIMO) system is proposed using an inverted U-shaped patch antenna. The antenna is fed by a coaxial feeding technique printed on a dielectric FR-4 substrate. The proposed MIMO system offers good return loss and isolation characterstics. This two element MIMO system produces dual band of frequencies with resonating frequencies at 2.8GHz and6.4GHz,which can be used for WLAN and satellite applications. The simulation results of return loss,mutual coupling and radiation pattern are presented in this paper.

Box‐folded four‐element MIMO antenna system for LTE handsets

A multiple-input–multiple-output (MIMO) antenna system for mobile handsets is presented. The proposed MIMO system consists of four identical box-folded planar inverted-F antenna. A broad operating band (1.84–2.69 GHz) with overall MIMO system dimensions of 136 × 68.8 × 6 mm3 and an element size of only 10 × 10 × 5 mm3 can be achieved. Lower than −14.2 dB isolation between any two of the elements has been obtained at the whole operating band. The correlation coefficient, radiation pattern and antenna gain are also studied.

Design of a compact MIMO antenna system with reduced mutual coupling

A novel compact multiple-input–multiple-output (MIMO) antenna system operating from 5 to 7.3 GHz is proposed for wireless applications. It comprises of two similar antennas with microstrip feeding and radiating patches developed on a reduced ground plane. The developed antenna system resonates at a dual-band of 5.4 and 6.8 GHz frequencies, giving an impedance bandwidth of 38% (based on S11 &lt; −10 dB). The unique structure of the proposed MIMO system gives a reduced mutual coupling of −27 dB at 5.4 GHz resonant frequency and −19 dB at 6.8 GHz resonant frequency and in the entire operating band the coupling is maintained well below −16 dB. The envelope correlation coefficient of the proposed MIMO system is calculated and is found to be less than 0.05 in the operating band. The measured and simulation results are found in good agreement.

High isolation and compact MIMO antenna system with defected shorting wall

In this paper, a compact multiple-input multiple-output (MIMO) antenna system with high isolation is proposed for 2.4 GHz wireless local area network (WLAN) application. The system is composed of two aperture-coupled shorted patch antennas with a spacing of 4 mm (only 0.032λ). The antenna is fed with an H-shaped coupling slot, and the defected shorting wall is used for high isolation. The proposed MIMO system exhibits an isolation of better than −20 dB and a maximum isolation of −43 dB at the central frequency. The envelope correlation coefficient is less than 0.01. The simulated and measured results show that the proposed antenna is a good candidate for MIMO system with higher isolation and better diversity.

Design of high port isolation access point MIMO system using centrally located hexahedron

A novel dual-band multiple-input multiple-output (MIMO) antenna system with diversity polarisation and high port isolation is proposed. The antenna system consists of six antennas (three antennas operate at 2.44 GHz and the others at 5.25 GHz) mounted on a hexagon ground plane and backed by a centrally located hexahedron. The antennas for different bands are arranged in an alternative fashion along the peripheral of the hexagonal ground. From simulation and experimental results, the proposed MIMO system has been shown to perform superbly at both the 2.44 and 5.25 GHz bands, with significant and consistent improvements in sidelobe levels and envelope correlation coefficients at the lower band due to the presence of the hexahedron.