5G Antenna Research Articles

Two-Dimensional Beam Steering Using a Stacked Modulated Geodesic Luneburg Lens Array Antenna for 5G and Beyond

Antennas for future communication systems are required to be highly directive and steerable to compensate for the high path loss in the millimeter-wave band. In this work, we propose a linear array of modulated geodesic Luneburg lens (the so-called water drop lens) antennas operating at 56–62 GHz. The lens array antenna features 2-D beam scanning with low structural complexity. The lenses are fully metallic and implemented in parallel plate waveguides (PPWs), meaning that they are highly efficient. Each lens is fed with 13 rectangular waveguides surrounded by glide-symmetric holes to suppress leakage. The lenses provide <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{110}^{\circ} $ </tex-math></inline-formula> beam coverage in the H-plane with scan losses below 1 dB. In order to scan in the E-plane, we use a feeding network based on a 1:4 power divider and three phase shifters. In this configuration, the array can scan <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{60}^{\circ} $ </tex-math></inline-formula> in the E-plane, albeit with higher scanning losses than in the H-plane. The lens array is manufactured and a good agreement between simulated and experimental results is obtained.

Multi-Beam 5G Antenna With Miniaturized Butler Matrix Using Stacked LTCC

Multi-Beam 5G Antenna With Miniaturized Butler Matrix Using Stacked LTCC

A 4 × 4 Millimeterwave-Frequency Butler Matrix in Grounded Co-Planar Waveguide Technology for Compact Integration With 5G Antenna Arrays

This article presents a novel <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> Butler matrix implemented in the grounded co-planar waveguide (GCPW) technology, compactly integrated with a highly efficient and broadband <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> air-filled substrate integrated waveguide (AFSIW) cavity-backed patch antenna array (AA), giving rise to a broad operational frequency range [23.75, 31 GHz] (26.5%) covering the n257, n258, and n261 fifth-generation (5G) bands. Three novel quadrature hybrid couplers and two crossovers are designed and compared to obtain the optimal building blocks for the Butler matrix. Within each of the supported 5G bands, the measured excess insertion loss of the optimized Butler matrix remains smaller than 3.5dB with a maximal amplitude imbalance of ±0.9dB. Isolation between input ports is higher than 16.4dB. A maximal measured realized gain of 12.3dBi is obtained for the Butler matrix with integrated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> AA while ensuring a −3-dB beamwidth coverage of 110°. The main beamsteering directions of [−40°, −14°, 14°, 40°] exhibit measured deviations that stay within ±3°. The fabricated Butler matrix with AA features a very compact footprint of 21.4 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$ </tex-math></inline-formula> 46.0 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 mm [ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\lambda _{0} \times 4.3\lambda _{0} \times 0.2\lambda _{0}$ </tex-math></inline-formula> ].

Epoxy-Nanoceramic Composites for 5G Antennas

Epoxy–nanoceramic composites of BiVO4 (BVO), LaNbO4 (LNO), and Li6Mg7Ti3O16 (LMT) were prepared using the solvent mixing method. The ceramic nano-fillers volume fractions were (5, 8, 10, and 12%). X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) were used to investigate the crystal structure and size distribution of nanoceramics, respectively. The dielectric constant and loss tangent were measured in the frequency range of (4-8) GHz. The measurement technique was the waveguide approach via a Vector Network analyzer (VNA). The effect of the volume fraction of ceramic fillers on the dielectric constant and loss tangent of the composites at 5.28 GHz (5G) was investigated. This work aims to design composite materials for 5G antennas of lower cost while maintaining the properties of 5G antennas. The results show that an optimum volume fraction of the ceramic filler brings the dielectric properties to their best value. However, epoxy composite with a 5% volume fraction of LMT shows good microwave dielectric properties (dielectric constant = 2.17 and loss tangent = 0.011) at 5.28 GHz. In addition, epoxy- LMT composite with an exceptionally low volume fraction of 5% provides a low-cost material for a 5G antenna. Another aspect of the cost reduction is the elimination of the costly and troublesome compaction and high-temperature sintering process. Furthermore, the epoxy composite overcomes the disadvantages of the high brittleness of the sintered all-ceramic products. As a result, epoxy composite with the 5% volume fraction of LMT is a potential candidate for 5G antenna materials.

Compact Wideband Self-Decoupled MIMO Antenna for 5G Communications.

A compact wideband self-decoupled multiple-input and multiple-output (MIMO) antenna is presented in this paper. The proposed antenna contains a pair of horizontal back-to-back elliptical tapered slots and a vertical elliptical tapered slot, which are etched on the circular metal patch. Based on characteristic mode analysis (CMA) and a suitable feeding structure, two desired characteristic modes (CMs) are excited. Therefore, across the entire matched bandwidth, a high level of isolation is realized without external decoupling structures. For validation, a prototype is fabricated and measured, and the measured results demonstrate that an impedance bandwidth of 3000 MHz with isolation higher than 20dB is achieved. Due to its self-decoupled property, high isolation, wide bandwidth, and compact size, the proposed antenna has excellent potential for 5G antenna array applications.

Durable, Low-Cost, and Efficient Heat Spreader Design from Scrap Aramid Fibers and Hexagonal Boron Nitride

Aramid, chemically known as para phenylene terephthalamide or PPD-T, has been widely used in the reinforcement of telecommunication cables, rubber materials (transmission belts, pneumatic belts), ballistic clothing, and frictional materials primarily due to their high tensile resistance, high elastic modulus, and excellent thermal stability (−80–200 °C). These unique properties of aramid originate from its chemical structure, which consists of relatively rigid polymer chains linked by benzene rings and amide bonds (-CO-NH-). Here, in this work inspired by these properties, a heat spreader called Thermal Interface Material (TIM) is developed by synthesizing a resin from scrap aramid fibers. When hexagonal boron nitride (h-BN) as filler is introduced into the as-synthesized aramid resin to form a thin film of thermal sheet (50 μm), an in-plane thermal conductivity as high as 32.973 W/mK is achieved due to the firmly stacked and symmetric arrangement of the h-BN in the resin matrix. Moreover, the influence of h-BN platelet size is studied by fabricating thermal sheets with three different sizes of h-BN (6–7.5 μm, 15–21 μm, and 30–35 μm) in the aramid resin. The results of the study show that as platelet size increases, thermal conductivity increases significantly. Since the resin reported herein is developed out of scrap aramid fibers, the cost involved in the manufacture of the thermal sheet will be greatly lower. As the thermal sheet is designed with h-BN rather than graphene or carbonaceous materials, this high heat spreading sheet can be employed for 5G antenna modules where properties like a low dielectric constant and high electrical insulation are mandated.

5G ДВУХДИАПАЗОННАЯ ПРЯМОУГОЛЬНАЯ МИКРОПОЛОСКОВАЯ АНТЕННА С ДВУМЯ ТРАВЛЕНИЯМИ И ВЕРХНИМ ШЕСТИГРАННЫМ ВЫРЕЗОМ НА КОНЦЕ CPW FED

Around the world, wireless or distant communication has become fundamental and indispensable.Every day, billions of users access calls, the internet, and social media. Many electricalequipment, including the antenna, are used in the sophisticated networks and systems that supportthat massive information interchange. An electrical device known as an antenna sends or receivesinformation across space. The antenna is a key component in many systems, including radio andtelevision transmission, communications receivers, radar, cellular phones, Bluetooth-enabledgadgets, and satellite communications. The rapid expansion of wireless technology and personalcommunication has increased the demand for multiband antennas, which can operate at severalfrequencies and are suited for a variety of applications. Dual-band coplanar waveguide (CPW)fed rectangular microstrip patch antenna for 5G, WiMAX band, ISM Band, and WLAN applicationsis presented in this paper. The proposed antenna is robust, cheap, light weight, and easy tofabricate, resonating at 2.4 GHz in -12.182379 s11 with 205.7 MHz BW and 3.42 GHzin -37.344879 s11 with 464.9 MHz BW whereas gain is 3.85 and 3.41 respectively. Patch elementsare placed on isolation FR408 (loss-free) substrate of relative permittivity 3.75 kept at a substrateheight of 1.6 mm. Results of simulation are presented using CST STUDIO SUITE 2019.

Design of a Compact Reconfigurable Sierpinski Gasket Fractal Antenna for 5G and Satellite Communications

Reconfigurability is one of the key features of 5G/6G radiofrequency systems. The possibility to adapt the working frequency depending on the application or the status of the nodes is important, especially in Smart Radio Environments. In this regard, the design of antennas operating at different frequency bands is challenging since strict requirements on the footprints and the radiation properties are introduced. Among other geometries, fractals present unique features in terms of small electrical lengths: they have been used for years by researchers to shrink antenna dimensions in a very effective way. An interesting perspective of these antennas is the possibility to switch the working frequency among several bands connecting/disconnecting the fractal cells. The aim of this paper is the design and the optimization of an electrically reconfigurable Sierpinski gasket fractal antenna. Four different states are obtained: in the first the device works at 27 GHz (mmWave), in the second at 16 GHz, in the third at 11 GHz (Ku-band), and in the fourth at 3.5 GHz (Sub-6GHz). The antenna operates efficiently in all the bands of interest.

Flexible Antennas for a Sub-6 GHz 5G Band: A Comprehensive Review.

The ever-increasing demand and need for high-speed communication have generated intensive research in the field of fifth-generation (5G) technology. Sub-6 GHz 5G mid-band spectrum is the focus of the researchers due to its meritorious ease of deployment in the current scenario with the already existing infrastructure of the 4G-LTE system. The 5G technology finds applications in enormous fields that require high data rates, low latency, and stable radiation patterns. One of the major sectors that benefit from the outbreak of 5G is the field of flexible electronics. Devices that are compact need an antenna to be flexible, lightweight, conformal, and still have excellent performance characteristics. Flexible antennas used in wireless body area networks (WBANs) need to be highly conformal to be bent according to the different curvatures of the human body at different body parts. The specific absorption rate (SAR) must be at a permissible level for such an antenna to be suited for WBAN applications. This paper gives a comprehensive review of the current state of the art flexible antennas in a sub-6 GHz 5G band. Furthermore, this paper gives a key insight into the materials for a flexible antenna, the parameters considered for the design of a flexible antenna for 5G, the challenges for the design, and the implementation of a flexible antenna for 5G.

A promising Ka band leaky-wave antenna based on a periodic structure of non-identical irregularities

This paper presents a new periodic grooved dielectric leaky-wave antenna with non-identical irregularities for an extremely high-frequency range capable of performing efficiently in the Ka band through a stable gain, a decrease in the level of the side lobes, and the achievement of a narrower main lobe beam. It consists of a dielectric waveguide antenna placed inside a channelled rectangular metallic waveguide to improve performance. A dielectric rod was used to overcome the losses related to the propagation of electromagnetic waves in metal conductors. A grooved dielectric of a 21-element linear array is used to propose a simple approach for the synthesis of such antennas based on a modified energy method and is fed by a standard waveguide. It was designed and simulated at 37.2 GHz for satellite, 5G antenna, and radar applications. The major novelty of this study is the ability to control the direction of the main lobe through non-identical irregularities in geometric parameters such as the width, height, and distance between each element. Radiation techniques have been extensively studied using simulations. A performance antenna with radiation efficiency of 99.35%, gain of 22 dBi, width of radiation pattern of 3.2 ^{circ }, and side lobe level (SLL) of {-} 18.3 dB has been achieved.

A High-Gain and Wideband MIMO Antenna for 5G mm-Wave-Based IoT Communication Networks

In this paper, an antenna with a multiple-input, multiple-output (MIMO) configuration is demonstrated for mm-wave 5G-based Internet of Things (IoT) applications. The two antenna elements are arranged next to each other to form a two-port antenna system such that significant field decorrelation is achieved. Moreover, a dielectric layer is backed by an eventual multiport system to amend and analyze the radiation characteristics. The overall size of the MIMO configuration is 14 mm × 20 mm, and the operation bandwidth achieves ranges from 16.7 to 25.4 GHz, considering the −10 dB criterion with a maximum isolation of more than −30 dB within the operating band. The peak gain offered by the antenna system is nearly 5.48 dB, and incorporating a dielectric layer provides an increase in the gain value to 8.47 dB. Within the operating band, more than 80% total efficiency is observed, and analysis shows several MIMO performance metrics with favorable characteristics. The compactness of the proposed design with high isolation, improved gain, and wideband features make it a suitable candidate for mm-wave-based 5G applications.

Symmetric Engineered High Polarization-Insensitive Double Negative Metamaterial Reflector for Gain and Directivity Enhancement of Sub-6 GHz 5G Antenna.

A symmetric engineered high polarization-insensitive double negative (DNG) metamaterial (MM) reflector with frequency tunable features for fifth-generation (5G) antenna gain and directivity enhancement is proposed in this paper. Four identical unique quartiles connected by a metal strip are introduced in this symmetric resonator that substantially tunes the resonance frequency. The proposed design is distinguished by its unique symmetric architecture, high polarization insensitivity, DNG, and frequency tunable features while retaining a high effective medium ratio (EMR). Moreover, the suggested patch offers excellent reflectance in the antenna system for enhancing the antenna gain and directivity. The MM is designed on a Rogers RO3010 low loss substrate, covering the 5G sub-6GHz band with near-zero permeability and refractive index. The performance of the proposed MM is investigated using Computer Simulation Technology (CST), Advanced Design Software (ADS), and measurements. Furthermore, polarization insensitivity is investigated up to 180° angles of incidence, confirming the identical response. The 4 × 4 array of the MM has been utilized on the backside of the 5G antenna as a reflector, generating additional resonances that enhance the antenna gain and directivity by 1.5 and 1.84 dBi, respectively. Thus, the proposed prototype outperforms recent relevant studies, demonstrating its suitability for enhancing antenna gain and directivity in the 5G network.

Rotational blow molding of thermotropic liquid crystal polymers and resulting orientational structure and mechanical properties

Liquid crystal polymers(LCP)is one of the most promising choices of 5G antenna material in the future, but its rigid rod-like macromolecular chain and the lack of melt elasticity make it difficult to produce film. In this paper, LCP film is successfully prepared based on a blow molding device developed in-house which the mandrel rotates in reverse with the outer die and the effect of annular shear on the orientation structure and mechanical properties of LCP film is investigated. SEM graphics show that obvious self-reinforcing fibers and the fiber cross structure are formed in the LCP film under the synergistic effect of annular shear flow field and axial extrusion. Polarization infrared pole diagram and 2D-WAXD results prove that the orientation degree of LCP film tends to be uniform with the increase of rotational speed. The tensile results show that the die rotation greatly reduces the gap between the longitudinal and transverse mechanical properties of the film, and even the transverse properties exceed the longitudinal properties at the rotational speed of 55 rpm. The LCP film with uniform mechanical properties is obtained eventually. • LCP film was successfully prepared based on a self-made blow molding device which the mandrel rotates in reverse with the outer die. • The rotation of the die made the LCP film formed a fibers cross structure. • The rotation die can effectively promote the orientation of the LCP molecular chain in all directions. • The transverse tensile strength of the RLCP55 exceeds the longitudinal strength.

Reconfigurable circular patch MIMO antenna for 5G (sub‐6 GHz) and WLAN applications

SummaryIn this article, a circular patch microstrip feed line monopole radiator with a dimension of 15 × 20 × 1.6 mm3 is proposed. An inverted L‐shaped stub is employed in the partial ground plane to achieve optimum bandwidth, radiation pattern and radiation efficiency. To further cover the sub‐6 GHz spectrum (3.4–3.8 GHz) for future 5G communications, a two‐element MIMO antenna configuration is designed by utilising the single element antenna. The edge‐to‐edge distance between the two elements is 0.15λ0 (15 mm). The propose antenna achieved dual‐operating bands of 3.35–4.60 and 4.93–5.19 GHz in the diode (D) = ON state. The minimum isolation between 3.35–3.94 and 4.99–5.16 GHz frequency range is −14.5 and −12.5 dB, respectively, by incorporating a rectangular stub between two inverted L‐shaped stubs. The MIMO antenna has a peak gain of 2.68 dBi at 5.1 GHz frequency. The average total efficiency at port‐1 between 3.35–3.94 and 4.93–5.19 GHz frequency range is 65%, whereas at port‐2 is 75%. In terms of the envelop correlation coefficient (ECC), mean effective gain (MEG) and total active reflection coefficient (TARC), the proposed antenna's diversity performance characteristics are investigated and the obtained values are 0.09, ±3 and −3 dB, respectively. The suggested MIMO antenna is designed on a FR4 substrate with a dielectric constant of 4.4 and an electrical dimension of 0.34λ0 × 0.20λ0 × 0.015λ0 mm3 (where λ0 represents the free space wavelength at lower cut‐off frequency [2.95 GHz]). Therefore, the proposed antenna can find applications for rain or fog as well as for identification and tracking (weather radar) on S‐band at 3 GHz frequency, 5G (sub‐6 GHz) and WLAN applications.

A compact four-band high-isolation quad-port MIMO antenna for 5G and WLAN applications

A miniaturized quad-port multiple-input-multiple-output (MIMO) antenna, generating four-band and high port isolation properties, is developed for 5G and wireless local area network (WLAN) applications. The realized MIMO antenna consists of four elements. Each element combines multiple L-shaped and rectangular branches with concave grounds, so that good impedance matching in four frequency bands is reached. The four elements are orthogonally placed to reduce current coupling. Moreover, four pairs of rotationally symmetrical strip lines are added to further improve the isolation between the units at low frequency. The antenna has been optimized to achieve a compact size of 39 mm × 39 mm × 1.6 mm, covering three 5G bands (2.6/3.5/4.8 GHz) and the 5.8 GHz WLAN band. In addition, inter-port isolation is better than 21.5 dB. Furthermore, the measured envelop correlation coefficient is smaller than 0.012 in the desired bands. Measurements also show that the radiation patterns and gains of the fabricated antenna agree well with the simulated ones. The diversity gain is as good as 9.94 dB. Moreover, the channel capacity loss is satisfactory, being below 0.4 bits/s/Hz. Satisfactory efficiency and diversity performance are realized. These facts indicate that the antenna system is a promising candidate for MIMO usage on 5G and WLAN devices.

A low profile antipodal Vivaldi antenna with improved front‐to‐back ratio and sidelobe levels for 5G applications

In this article, a novel miniaturized antipodal Vivaldi antenna (AVA) is proposed with significant improvement in the back and sidelobe levels (SLLs) to mitigate their adverse effect on the communication system components. The proposed AVA enhances SLL up to −5.7 dB and front to back ratio (FBR) to 20.2 dB. These improvements are accomplished by antenna size reduction and gain enhancement. The proposed AVA is miniaturized by 22.27% and the gain is increased up to 4 dBi compared to the conventional AVA (CAVA). The AVA is designed by incorporating substrate integrated waveguide (SIW) and corrugations. The use of corrugations improves the FBR and gain. Next, the improvements in the bandwidth and SLL are achieved by SIW. The antenna dimensions are 15 × 6 × 0.5 mm3 and it provides the enhanced and almost constant gain of 9.5 ± 1.5 dBi. The antenna is designed for the 38 GHz band of 5G applications and it has an impedance bandwidth of 36–48.43 GHz. The efficiency of an antenna is above 94% over the desired frequency range. The antenna is fabricated and verified with experimental results. The proposed antenna makes it as one of the best choices as a 5G antenna.

CSRR and open-stub based circular polarized and double band eight-ports MIMO antenna for 5G and ISM band applications

CSRR and open-stub based circular polarized and double band eight-ports MIMO antenna for 5G and ISM band applications

UWB Microstrip Patch Antenna with 5G Lower Band Notch Characteristics

For fifth generation (5G) lower band wireless application at a frequency of (4.5–5.5) GHz, recently ASEAN region countries have suggested 5G forums and band rejection antennas for 5G (4.5–5.5) GHz lower band. A UWB antenna has been constructed and suggested by use of the Roger RT5880 with defected ground on a rectangular radiating patch and a ring shape type of resonator (RSR) on ground plane to achieve the desired performance. It was decided to construct a band rejection within UWB antenna for 5G which included adding a rectangular slot on the radiating patch as well as placing RSR to the ground plane of the proposed antenna. The results support the theory that the antenna is capable of transmitting and receiving in the UWB except band notched bandwidth. Additionally, the results show that the antenna possesses good performance across the whole UWB spectrum with a gain of 4.6 dBi. This, in addition to its ability to support the lower 5G band notched, is why the suggested antenna is a good contender for future 5G wireless implementations within UWB bandwidth.

Wideband Antenna for High-Frequency 5G Wireless Communication

In this study, a wideband patch array antenna for high-frequency 5G wireless communication is proposed. The wideband high-frequency 5G antenna is needed to handle the increase in 5G data traffic. The proposed antenna, a 2 × 16 element array with gap-coupled parasitic elements and a multi-section or stepped transformer feeding network with feed cover to prevent unwanted feed radiation, can cover 5G new radio (NR) n257 (26.5–29.5 GHz), n258 (24.25–27.5 GHz), and n261 (27.5–28.35 GHz) bands. Using parasitic elements with a single substrate instead of cavity and stacked structures, a wide impedance bandwidth (dB magnitude of S&lt;sub&gt;11&lt;/sub&gt; &lt; –10) of 24.2% (23.75–32 GHz) is achieved. A high cross-polarization discrimination (XPD &gt; 25.2 dB) is achieved using orthogonal dual polarization. The peak gain obtained is 18.69 dB.

Flexible interconnected 4-port MIMO antenna for sub-6 GHz 5G and X band applications

A flexible 4-port 4-element interconnected MIMO antenna is proposed for Sub-6 GHz 5G and X-band applications. The 4-element structure attains a low profile of 0.612λ2 (at 3.34 GHz) through careful placement of antenna elements. The elementary antenna top side is formed of an inverted E and inverted L-shaped conductive structure attached to both sides of the central feed line. Two hollow tilted square-shaped assemblies are added horizontally with the inverted L for performance enhancement. The bottom plane consists of a truncated ground with a vertical stub on the side for achieving wideband performance. The MIMO configuration along with polarization diversity is attained by positioning the elementary antenna symmetrically in a sequential rotational manner. The interconnection between ground planes is ensured by placing an I-shaped strip which is further modified by adding a slotted rectangular stub on the central vertical line for better isolation. The flexible antenna demonstrated minimum efficiency and maximum gain of 70% and 4 dBi, respectively in addition to accomplishing a bandwidth of (40%) 3.34–5.01 GHz and (3.31%) 8.9–9.2 GHz while satisfying the MIMO diversity performance in terms of envelope correlation coefficient (ECC) < 0.17. Finally, the antenna performance in terms of S-parameters and MIMO diversity parameters are tested by bending the antenna along the X and Y axis that demonstrated decent performance thus making the MIMO antenna worthy for its use in Sub-6 GHz 5G and X Band Applications with tight space requirements.