Sub-6 GHz 5G Research Articles

Compact metamaterial-based single/double-negative/near-zero index resonator for 5G sub-6 GHz wireless applications

The concept, performance, and analyses of distinctive, miniaturized metamaterial (MTM) unit cell addressing the forthcoming Sub 6 GHz 5G applications are presented in this paper. Two circular split-ring resonators (CSRR) with two parallel rectangular copper elements in front of the design and a slotted square element in the background make up the suggested metamaterial. It has a line segment with tunable features that is positioned in the center of the little ring copper structure. The suggested design offers a significant operating frequency band of 220 MHz together with a resonance of transmission coefficient S21 at 3.5 GHz. Furthermore, in two (z & x) principal axes of wave propagation, wide-range achievement, single/double-negative (S/DNG) refractive index, negative permittivity, and near-zero permeability properties were demonstrated. Through varying central slotted-strip line length, resonance frequencies can be selectively altered. Moreover, the metamaterial has overall dimensions of 9 × 9 mm2 and is composed on a Rogers 5880 RT substrate. In order to create the suggested MTM's equivalent circuit, which shows similar coefficient of transmission (S21), a proposed design’s numerical simulation is carried out in the CST micro-wave studio. This simulation is after that put to comparison with manufacturing of the design.

Compact dual-band antenna design for sub-6 GHz 5G application

A design of a compact dual-band antenna for 5G application is presented in this research article. The dual-band operation includes the 3.6 GHz and 5.4 GHz frequency bands of the sub-6 GHz frequency band for 5G technology. The proposed antenna offers a compact design with satisfactory antenna performance parameters. Moreover, the dual-band antenna showcases the independent tuning ability for both frequency bands. The prototype of the dual-band antenna is manufactured and when tested for various antenna performance parameters shows a good agreement between the simulated and measured results. The proposed dual-band antenna has compact dimensions along with a peak gain of 2.2 dB and antenna efficiency of more than 90%.The antenna performance parameters are also compared with various dual-band antenna designs from the literature. The proposed dual-band antenna offers a compact design with satisfactory performance parameters and outperforms its counterparts.

Design of a novel compact low specific absorption rate multiple input multiple output antenna for 5G sub-6 GHz terminals

This investigation presents a new design and analysis of a fourteen elements massive multiple input multiple output (MIMO) compact low specific absorption rate (SAR) antenna system for 5G and beyond terminals. The MIMO antennas are realized for sub-6 GHz LTE-band 46 (5.1-5.8 GHz) long-term evolution 5G wireless communication services. The proposed antenna system is designed on an FR-4 dielectric constant 4.3 substrate consisting of the main board and four sideboards. The radiating elements are developed on the sideboards consisting of a monopole antenna and two metamaterial unit cells, as well as the feed line is designed on the principal board. The overall volume of the proposed structure is 150×80×7.5 mm. Through the use of the metamaterial unit cells, the proposed antennas have been arranged in close proximity without developing a strong mutual coupling. The results obtained were very important in terms of impedance matching, isolation among the antennas, and good gain. Even, the SAR analysis at the operating frequency band of 5.5 GHz proves that the proposed MIMO antenna system satisfies safety standards set for human exposure at the international level. Therefore, the proposed massive MIMO antenna structure is a potential solution for future communication applications.

Gain and radiation pattern enhancement using ANN-based reflector antenna for full 5G Sub-6GHz applications

Gain and radiation pattern enhancement using ANN-based reflector antenna for full 5G Sub-6GHz applications

Tri-band antenna with metasurface-based ground plane for Sub-6 GHz 5G and 6G WPT applications

In this paper, a spiral-shaped metamaterial-loaded rhombic slotted microstrip patch antenna is investigated for Sub-6 GHz 5G and 6 GHz tri-band applications. A 1.524 mm thick Rogers RO4003 substrate (ϵr = 3.55, LosTanδ = 0.0027) opts for the antenna design. A partially grounded mechanism is implemented to control the operating frequencies of the antenna. A 5×5 triangular unit cell metasurface is deposited beside the partial ground plane to enhance the impedance bandwidth as well as to improve the impedance matching. A G-shaped metallic structure enclosed within the rhombic slotted antenna helps in creating circular polarization (CP) properties. The presented antenna resonates at 3.28 GHz (Mid-range Sub 6 GHz 5G band), 4.94 GHz (Upper range Sub 6 GHz 5G band), and 6.92 GHz (Sub 6 GHz 6G Band) frequencies. The maximum gain offered by the antenna is 8.81 dBi. Also, the developed antenna offers CP characteristics in all three operating bands with wide axial ratio (AR) bandwidth characteristics above 400 MHz in both the first and third operating bands. The radial characteristics of the proposed antenna show its capability of receiving EM signals from all directions as desired for a WPT system. For validation purposes, a prototype is fabricated and characterized as well.

Metamaterial-Inspired Electrically Compact Triangular Antennas Loaded with CSRR

In this paper, simulation of two distinct kinds of metamaterial (MTM) antennas are proposed for fifth generation (5G) indoor distributed antenna systems (IDAS). Both antennas operate in the sub-6 GHz 5G band, i.e., 3.5 GHz and to analyze various factors like gain, directivity, return loss, radiation intensity for the frequency of 3.5 GHz. The simulation of this metamaterial antenna is carried out in ANSYS HFSS v2021. Results like return loss, radiation pattern, 3D polar plot, side lobe level, beamwidth, radiated power, accepted power have been obtained using HFSS v2021. This research on metamaterial gives a great view on how it can be designed and used at 3.5GHz frequency has a measured gain/bandwidth characteristic of 100 MHz/2.6 dBi and 700 MHz/2.3 dBi, respectively. The main advantage of this antenna is it can be used as both transmitting and receiving antenna. Key Words: Metamaterial, CSRR, return loss, triangular CSRR

Performance analysis of quad-port UWB MIMO antenna system for Sub-6 GHz 5G, WLAN and X band communications

A quad-port Multiple Input Multiple Output Antenna with high isolation is presented in this paper. The MIMO design is intended to receive Ultra-Wide Band response to target various wireless applications. The engineered model has 40 x 40 × 1.6 mm3 electrical dimensions. A single antenna achieves size compactness due to an appropriate inclusion of vertical and horizontal conductive strips. Additionally, a diagonal radiating strip is shaped and pooled with the patch geometry. A similar design is positioned orthogonally with each other to receive diversified performance. The four conducting ports are positioned with an appropriate minimum distance to lower down the possible mutual coupling. A partial ground plane having border geometry has been incorporated to receive the ultra-wide band response. An additional plus-sign shaped conducting strips are provided and united with ground lines for isolation enhancement. The MIMO system exhibits ultra-wide frequency response from 3.20 GHz to 13.40 GHz with adequate isolation below −20 dB and an impedance bandwidth of 10.20 GHz. The proposed structure provides an overall gain of 2 dBi having above 80 % efficiency. The presented radiator exhibits excellent MIMO diversity response achieving minimal mutual coupling effect. The other output parameters such as envelope correlation coefficients<0.05, diversity gain of nearly 10 dB, mean effective gain<0.2 dB, and channel capacity loss<0.1 bits/sec/Hz were obtained. The proposed design has been simulated in High Frequency Structure Simulator (HFSS) software. The developed MIMO antenna has been analyzed through VNA N9912A. An encouraging correlation between the software generated and actual responses was observed. The strong agreement between actual results and software results shows the design potential for wireless communications. The highly isolated MIMO system registers its potential for sub-6 GHz 5G, WLAN, and X Band communications.

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.

Enhancing gain and isolation of a quad-element MIMO antenna array design for 5G sub-6 GHz applications assisted with characteristic mode analysis

This paper presents a novel quad-element array with multiple inputs and multiple outputs (MIMO) designed for 5th generation sub-6 GHz applications. The MIMO system achieves a wide impedance bandwidth, high gain, and high isolation among its components, representing significant advancements in sub-6 GHz antenna applications. The single element, an elliptical resonator with a circular slot, is fed by a 50 Ω microstrip feedline, achieves a broad characteristic bandwidth from 3.7 to 5.7 GHz with a resonant frequency of 4.33 GHz and a gain of 1.81 dBi. Characteristic Mode Analysis (CMA) was employed to elucidate the evolution phases of this design. The quad-element MIMO antenna array maintains a compact size and broadband characteristics by arranging mirrored elements on the same ground plane. Implemented on a cost-effective FR-4 substrate measuring 44 × 44 × 1.6 mm3, the recommended MIMO antenna array, enhanced with a partial ground plane and due to the introduction of a vertical strip, a high isolation of − 38.53 dB is achieved between MIMO components along with a realized gain of 3.01 dBi and a radiation efficiency of 71% in the 5G sub-6 GHz band. Noteworthy properties include high isolation, diversity gain (DG), and envelope correlation coefficient (ECC), verifying the appropriateness of the suggested MIMO scheme for 5G transmission and reception in sub-6 GHz applications.

Absorption of 5G sub-6 GHz electromagnetic radiation from base station to male reproduction system

Background The impact of electromagnetic radiation from communication on the male reproductive system has emerged as a significant concern in public health. A notable distinction of the 5G sub-6 GHz band, compared to traditional 2G, 3G, and 4G frequency bands, is the inclusion of higher frequency bands. This has raised public concerns regarding the potential effects of these higher frequencies on organisms, particularly their reproductive systems. While it is imperative to investigate the biological effects and potential risks associated with these new frequency bands in laboratory settings, comparing and evaluating differences between various frequency bands remain challenging due to the absence of standardized parameters such as exposure conditions and duration. In contrast, dose assessment offers a simpler and more reliable approach. Materials and methods The dose assessment method was employed in this study to investigate the risks associated with sub-6 GHz electromagnetic radiation from 5G base stations on the male reproductive system. A classical human body model (Duke) was utilized, and an electromagnetic simulation environment was established based on the actual polarization direction of the exposed base stations and various body postures. This research explored the effects of field direction, posture, public population, and frequency on the specific absorption rate of the reproductive system. Results and conclusions While maintaining the same level of exposure, a higher frequency results in a reduced dosage on reproductive system. Further analysis reveals that, considering the public exposure threshold, the employment of higher frequency bands in 5G sub-6 GHz does not present a greater dosage on reproductive system compared to lower frequency bands. Consequently, with regard to dosage, there is no need for excessive concern among the general public regarding the impact of electromagnetic radiation emitted by 5G base stations operating below 6 GHz on male reproductive health.

Design and development of low-profile hybrid reconfigurable antenna for 5G sub-6 GHz applications

This paper reports a low-profile hybrid reconfigurable antenna for 5G sub-6 GHz applications, measuring 14 × 15 × 0.787 mm3. A hybrid, frequency-and pattern-reconfigurable antenna with a semi-circular patch makes up the design. The Rogers RT5880 substrate, having a dielectric constant of 2.2, is used to build the design. Two PIN diodes are employed in the top layer to reconfigure frequency, and two diodes are used in the bottom layer to achieve pattern reconfigurability. Inverted L-shaped stubs and a defective ground structure (DGS) are put onto the antenna's ground plane. The ground plane uses the DGS to cover the necessary sub-6 GHz frequency spectrum. The suggested design covers two distinct frequency bands having −10 dB impedance bandwidth of 260 MHz for 3.4 GHz-3.6 GHz when the top layer diodes are ON and 270 MHz for 3.6 GHz-3.8 GHz when they are OFF. In addition, the suggested design is manufactured and tested, and the simulation and measurement resultsshow good association.

FSS based high gain optically transparent MIMO antenna for Sub-6 GHz 5G mid-band applications

A novel optically transparent Multi Input Multi Output (MIMO) antenna design positioned on a Frequency-Selective Surface (FSS) for gain improvement while maintaining a simple fabrication procedure. Transparent conductive materials inherently exhibit higher sheet impedance due to lower conductivity, resulting in decreased antenna gain and radiation efficiency. To address this limitation, an optically transparent FSS is incorporated beneath the MIMO structure to improve radiation characteristics. Utilizing a Malinex substrate and a conductive silver oxide sheet, the 4-element MIMO design achieves both transparency and MIMO operability. The operational bandwidth spans from 3.09 GHz to 3.7 GHz, with a percentage bandwidth of 17.96 %, ensuring port isolation of over 20 dB. With the presence of the FSS, a consistent gain enhancement of approximately 3.46 dBi is achieved, with an average gain within the band reaching 4.56 dBi. The proposed design employs a simplified fabrication process while addressing aesthetic concerns and providing a solution to the existing issue of low gain in conductive metal oxide-based transparent antennas.

Assessment of the potential threats to brain health posed by the radiation from 5G sub-6GHz base stations in China using dosimetric methods.

The 5G sub-6GHz radio frequency (RF) electromagnetic fields (EMF) are the most widely used in China's communications. The public has expressed concerns about possible brain health effects of the higher frequency bands in 5G compared to 2G, 3G, and 4G bands. It is imperative to empirically investigate the potential health hazards of these novel frequency bands in 5G communication technology. This study evaluates the assessment of brain tissue dose coupling from sub-6GHz band EMF emitted by base stations in China. Based on the 3D virtual human body model, the simulation environment was established. Dose including specific absorption rate (SAR) and internal electric field (IEF) between 2G, 3G, and 4G bands and 5G sub-6GHz was investigated using normalized exposure values and exposure limits. The results indicate that the sub-6GHz high-frequency band of 5G has the lowest dose value. It can be concluded that high-frequency electromagnetic radiation in 5G sub-6GHz reduces the dose and health threats to the brain. This provides strong support for the promotion of 5G commutation in China and other regions.

Split ring resonator geometry inspired crossed flower shaped fractal antenna for satellite and 5G communication applications

This work suggests a fractal antenna in the shape of a crossed flower with a split ring resonator geometry. This suggested antenna serves the Sub-6 GHz 5G and satellite repeater applications for wireless devices operating in the frequency range of 4.01–4.82 and 7.6–7.94 GHz, respectively. The suggested antenna's performance parameters have been empirically confirmed by creating a printed prototype. The antenna geometry is based on a lower-cost FR4 substrate and consists of a mix of crossed floral square-shaped split-ring resonators organized in a Minkowski fractal configuration. A thorough examination of both manufactured and simulated antennas is conducted to demonstrate the uniqueness and edge over traditional dual-band antennas. The suggested fractal antenna's overall physical dimensions measure 0.90λ x 0.96λ at a lower resonant frequency. The response of the unit cell antenna is recorded when Split Ring Resonators are grouped in a fractal antenna with a flower shape. The measured findings verify that the proposed and constructed antenna has an electrical impedance bandwidth of −10 dB at lower frequency band (18.80 %, 4.01–4.82 GHz) and upper frequency band (4.41 %, 7.6–7.94 GHz) of −10 dB. The simulated and fabricated prototypes exhibit good agreement with respect to the stable gain and radiation patterns. Because of its consistent radiation efficiency in the realized resonating bands, the suggested prototype is a strong contender for 5G Sub-6 GHz and X band satellite applications.

Advanced GaN Wideband/Multiband Power Amplifier for Sub-6 GHz 5G and Beyond Wireless Communication: Toward Future Flexible Base Station by AI-Based Digital Assisted PA

Advanced GaN Wideband/Multiband Power Amplifier for Sub-6 GHz 5G and Beyond Wireless Communication: Toward Future Flexible Base Station by AI-Based Digital Assisted PA

A simple 90° hybrid branchline coupler with wideband phase balance for 5G applications

Abstract A 90° hybrid coupler operating at a central frequency of 5.40 GHz is introduced, offering high-performance characteristics with compact dimensions of 616.65 mm&amp;sup2; (33.3 mm × 18.5 mm). These features are achieved while maintaining a design that makes it easy to produce. The unique aspect of this microstrip FR4 substrate-based design is the consistent S-parameters, which remain steady despite changes in structural dimensions, thereby making it adaptable to fabrication variations. The reported S-parameters measured in 5.4 GHz are as follows: |S11|= –29.46 dB, |S21|= –4.11 dB, |S31|= –3.96 dB, and |S41|= –21.23 dB. This hybrid coupler operates over a bandwidth of 0.8 GHz (16%), demonstrating remarkable performance within this spectrum. In addition to its design, the coupler exhibits robust resilience against changes in substrate parameters and structural dimensions, ensuring reliability during the fabrication process. Following thorough simulation studies, a physical prototype of the coupler was constructed and subjected to laboratory measurements. The experimental results align closely with the simulation data, validating the accuracy and predictability of the design. In comparison with other studies and designs documented in the literature, this compact, high-performance 90° hybrid coupler exhibits clear advantages in terms of size, isolation, phase deviation, and structural complexity. Therefore, the benefits and applicability of this presented structure in the context of microwave circuits and systems are underscored. It’s noteworthy to mention that the central frequency of 5.4 GHz falls within the sub-6 GHz 5G band range.

Phase delay through slot-line beam switching microstrip patch array antenna design for sub-6 GHz 5G band applications

Two, four, eight, and sixteen-element patch array antennas for beam switching are presented in this study. For a 1×2 array, an aperture-coupled feeding mechanism is used to feed patches while a slot line on the ground plane provides the phase delay between antenna elements. The 1×2 array is used to create the 2×2, 4×2, and 8×2 arrays, and an equal power divider provides the signal for each. For applications in the 5G sub-6 GHz frequency spectrum, the antennas are modeled. With -37.14 dB, -17.85 dB, -21.51 dB, and -26.03 dB return loss for two, four, eight, and sixteen-element array antennas respectively the simulation demonstrates that the antennas are properly matched at the resonant frequency. The antennas can switch its radiated beam to ±24&lt;sup&gt;o&lt;/sup&gt;, ±24&lt;sup&gt;o&lt;/sup&gt;, ±28&lt;sup&gt;o&lt;/sup&gt;, and ±26&lt;sup&gt;o&lt;/sup&gt; with gains of 8.97 dBi, 11.19 dBi, 13.23 dBi, and 16.24 dBi, respectively at the resonance frequency. The directivity of the proposed antenna is found to be 9.17 dBi, 11.20 dBi, 13.40 dBi, and 16.45 dBi respectively. The antennas are constructed with two 0.8 mm-thick Teflon substrate layers. The ground plane between the two substrate layers contains the aperture and the slot line that generates the phase delay.

Enhanced performance of microstrip antenna fabricated on a composite dielectric substrate coupled with multiple dielectric superstrates

In this study, we introduce a unique geometrical design of a rectangular patch antenna for sub-6 GHz 5G applications. The proposed antenna is designed at 5.2 GHz, and design criteria and performance characteristics have been investigated through numerical simulations and verified using measured data. A composite structure is suggested to overcome the restrictive parameters of conventional antennas. Two different materials, Rogers RT5880, and RT5870, are utilized, achieving a maximum gain of 6.210 dB, and a 90.2% radiation efficiency was attained. Four layers of superstrates are placed above the antenna to enhance the antenna's radiation performance further. The fabricated antenna is evaluated by measuring its radiation characteristics and return loss. The final antenna prototype offers a maximum bandwidth of about 896 MHz at a −10 dB reflection coefficient with a maximum gain of 9 dB. The proposed model achieved ultimate efficiency as high as 89% by employing four superstrates. The results showed good impedance matching (S11, VSWR), high efficiency, and appropriate radiation patterns. The outcomes from simulation and measurement are well aligned, making this antenna suitable for high-performance 5G applications.

Multiband SINC-slotted Patch Antenna for 5G Applications

In this work, we presented the design, analysis and optimization of the multiband slotted antennas based on SINC function for 5G applications. The proposed antennas are designed and modelled by CST Studio Suite software. A parametric study is performed to determine sinc function parameters that control the performance of the proposed antenna. The parametric study is implemented by varying the amplitude of the sinc function, the frequency, the location of the slot along Y-axis, the slot width and the slot window (number of cycles). The simulated results showed that the designed slotted antennas in this paper exhibits multiband operation and they offer the feasibility of controlling and adjusting the resonant frequency by changing the sinc function parameters. The proposed antennas have various resonant frequencies at around 1.5 GHz, 2.65 GHz, 5 GHz and 5.8 GHz covering the 5G sub-6 GHz band. Extensive simulation process were carried out to determine the optimum antenna performance and three antennas were selected based on the reflection characteristics and number of operation frequency bands. Finally, the three selected antennas were manufactured and their performance were measured in the lab for validation. Experimental results showed that an excellent agreement between the measured and simulated results was achieved.

Sub-6GHz hand pump shaped microstrip antenna for 5G communication

The purpose of this paper is to explore the presented design of a hand-pump shaped microstrip antenna for sub-6 GHz 5G communication. This paper will first provide a brief overview of the antenna design and its capabilities. Meaning, overall impressive dimensions of 25.25 mm x 20.75 mm x 1.55 mm, with S11 being -16.82 dB at operating frequency of 5.16 GHz. Next, the paper will discuss the design of the antenna and how it can be optimized with a sub-6 GHz operating frequency, along with requirements. To reach the required specifications, inc. E- ≥ 5 GHz ≥ E-φ; S11 ≤-10, various geometrical parameters, among others, have been tested, resulting in two slots being added (slot a and slot b), in combination with various slits. Finally, an antenna is produced, and laboratory measurements are carried out for the validation of the results. Further discussing the potential benefits and drawbacks of using this antenna design for 5G applications.