Azimuth Plane Research Articles

A System-Performance-Based Comparison of Sparse Regular and Irregular Antenna Arrays for Millimeter-Wave Multi-User MIMO Base Stations

A system-level study was conducted that evaluated the system performance of various dense and sparse antenna array configurations for application in millimeter-wave multi-user multiple-input multiple-output base stations. The performance was evaluated by investigating the probability that a user experiences an outage when a zero-forcing pre-coder is used in a random line of sight scenario. This paper shows that the outage probability significantly decreased when irregular sparse arrays were used rather than regular sparse or regular dense arrays. A re-configurable linear array was designed and realized as a demonstrator. It used 3D-printed aluminum box horn antenna elements that had wide scanning range in the azimuthal plane and a small scanning range in the elevation plane. For the demonstrator, it was shown that the outage probability was reduced from 3.85% to 0.64% by moving from a sparse regularly spaced array to a sparse randomly spaced array. This amounted to an improvement of a factor of six. The sparse topology allowed for the usage of large antenna elements that had an increased gain and still achieved wide-angle scanning, while reducing mutual coupling to a minimum.

Sub-6 GHz and mm-Wave 5G Vehicle-to-Everything (5G-V2X) MIMO Antenna Array

A multi-beam and multi-polarized Multiple-Input Multiple-Output (MIMO) antenna system, which operates at Sub-6 GHz and mm-wave frequency bands is realized for 5G Vehicle-to-Everything (5G-V2X) application. Since the vehicle needs to communicate in different scenarios with the others, e.g. vehicles, passengers, control units, and mobile networks, in the surrounding area, an antenna with 360° coverage area is required. In this paper, an eight-element MIMO antenna is designed and implemented for this purpose. Four elements are distributed evenly in a circular substrate placed in the azimuth plane. Meanwhile, the other four elements are printed on two orthogonal substrates which are fixed perpendicularly to the circular substrate. Each radiating component is a tapered slot antenna integrated with a dipole to operate at both microwave and mm-wave bands. The simulated and measured results demonstrate capability of the proposed design in covering the whole surrounding area (360° coverage in azimuth plane). The antenna achieves a realized gain of more than 9 dBi at the mm-wave range and 4 dBi at the microwave range.

A Dual Slant-Polarized Cylindrical Array of Tightly Coupled Dipole Antennas

This study proposes a design of a low-profile ultra wide-band cylindrical antenna array with plus/minus 45-degree dual polarization. The proposed compact cylindrical antenna array produces an omnidirectional radiation pattern in the azimuth plane to cover all directions. It consists of <inline-formula> <tex-math notation="LaTeX">$20\times 4$ </tex-math></inline-formula> dual-polarized elements within a diameter of 131 mm and a height of 116 mm. The array elements are tightly coupled slant-polarized wideband dipole antennas, and hence, rotational symmetry of radiation patterns in the horizontal plane is achieved for the two orthogonal polarizations. Furthermore, a metasurface structure has been designed and placed over the interconnected array elements to achieve ultrawideband capabilities. The proposed array provides less than &#x2212;10 dB reflection coefficient over a frequency band between 1.7 GHz and 5.9 GHz. The cross-polarization discrimination (XPD) is 15 dB at boresight in the azimuth plane. The electromagnetic characteristics of the cylindrical array and its corresponding planar array before bending have been evaluated and compared via simulations, and verified by measurements. The compact size, lightweight, and printable design of the proposed antenna array enable low-cost manufacturing and ease of installation. The proposed array design overcomes many challenges encountered in wide-band MIMO systems by covering the entire sub-6 GHz band while providing wide 360-degree coverage in the azimuth plane, hence, supporting multibeam applications.

Experimental investigation of performance of high-shear atomizer with discrete radial-jet fuel nozzle: mean and dynamic characteristics

The present study focuses on the performance of a novel high-shear atomizer with a discrete radial-jet fuel nozzle to overcome the constraints associated with the simplex-pressure-swirl and duplex-fuel nozzles at the high-end power demand of a gas turbine combustor. The high-shear atomizer consists of multiple inner and outer radial swirlers with interchangeable flare and fuel nozzle. The performance of the atomizer with discrete radial-jet fuel nozzle is elucidated at ALR (mass ratio of air to liquid) 14.1 through variations in geometrical design parameters of the swirl cup. The parameters of interest are the split ratio (γ), relative swirl direction of inner and outer swirler (co- and counter-rotation), flare angle (θ) and flare mixing length (η). Spray characteristics at ALR 4.72, 7.08 and 9.44 are also presented for an atomizer by freezing the geometrical design. The particle image velocimetry diagnostic technique is employed to capture the spray flow field. The non-dimensional radial (W/Df; W, radial width of CTRZ (in mm) and Df, exit diameter of flare (mm)) and axial (L/Df) sizes of the central toroidal recirculation zone and near field swirl number (SN5) of the flow are explored. Further, variations in the droplet size distribution of the atomizer across all the ALR are discussed in detail. The Sauter mean diameter across all the test cases is found to be in the range of 9–30 μm, 15–37 μm, 15–50 μm and 23–75 μm at ALR 14.1, 9.44, 7.08 and 4.72 respectively, which shows good atomization capability of the atomizer with discrete jets. The spatial distribution of the spray volume/mass in an azimuthal plane is examined in the circumferential and radial directions, which shows consistent and excellent azimuthal symmetry of the spray even with a decrease in ALR value. The overall mean and dynamic spray characteristics of the atomizer suggest that high-shear atomizer in combination with a discrete radial-jet fuel nozzle would be a better candidate than an atomizer with a simplex pressure-swirl fuel nozzle in rich-quench-lean concept-based gas turbine combustors.

Cross-Slotted Waveguide Array With Dual Circularly Polarized Radiation at W-Band

This article discusses the design of a cross-slotted waveguide array structure to be adopted for W-band communication between 84 and 86 GHz. Each array waveguide element contains 16 cross-slots along the broad wall to enable circularly polarized radiation behavior with a gain reaching up to 14 dBi and a cross-polarization isolation of more than 20 dB in the elevation plane. The design of the cross-slots is implemented with bent arms in order to accommodate them at an offset position from the waveguide narrow wall. Such position ensures the radiation of a circularly polarized wave. A waveguide-based feeding network with serpentine-shaped transitions is implemented to feed the eight-element cross-slotted array topology. The design of the feeding network ensures an equal power split and in-phase distribution between the eight elements with a phase deviation that does not exceed 20°. The overall cross-slotted waveguide array is prototyped as a proof of concept. The measured results show a maximum gain of 24.5 dBi for both polarization schemes. The measured half power beamwidth (HPBW) is 8° in the elevation plane and 12° in the azimuthal plane. The measured cross-polarization between the two circularly polarized schemes at both ports reaches a level of more than 26 dB. The comparison between the simulation and measurement results proves the validity of the proposed approach in achieving a high-gain dual circularly polarized structure for millimeter-wave communication.

Packable and Readily Deployable Tightly Coupled Dipole Array (TCDA) With Integrated Planar Balun

To overcome the limited payload dedicated to onboard antennas for CubeSat/SmallSat applications, this paper presents a novel, foldable, dual-polarized Tightly Coupled Dipole Array (TCDA). In comparison to previous vertical feeds used for TCDAs, this array integrates a planar microstrip balun feed to enable foldability. The proposed array attains 5.4:1 (0.6-3.20 GHz) impedance bandwidth with VSWR < 3 at broadside and scans down to 45∘ at all azimuth planes. Notably, a substrate-integrated in-plane folding mechanism based on Lamina Emergent Torsion (LET) joints is employed to achieve foldability coupled with a simple fabrication process. The average simulated radiation efficiency was 95% across the band. A 5 × 8 prototype array was fabricated and tested to verify the finite array’s foldability, bandwidth, and gain performance. This prototype achieves 80% one-dimensional size reduction, yielding 60% overall volume reduction. Consequently, the array prototype can be folded and stowed in a compact volume of 1.4U ( 25 cm× 7.2 cm× 9 cm ).

Annular Surface Plasmon Polariton-Based Frequency-Scanning Leaky-Wave Antenna for Full Azimuth Coverage

This article presents a single-layered annular surface plasmon polariton (SPP)-based leaky-wave antenna (LWA) for full azimuth beam scanning in 60 GHz applications. The groundless annular SPP transmission line (TL) has a special feeding mechanism that can be operated at 60 GHz in the SPP mode. Periodically radiating circular patches with gradually smaller sizes near the TL create an additional momentum that helps convert the slow wave SP mode into the radiating leaky mode. This results in frequency-dependent continuous beam scanning in the azimuth plane. The theoretical, numerical, and experimental results of the proposed device agree well. The antenna has an overall scanning range of 268°, −10 dB impedance BW of 15.33%, and a peak gain of 19.7 dBi with an average sidelobe level (SLL = −10 dB) and a cross-polar level of −20 dB. Owing to the low-profile compactness and improved performance, the proposed single-layered LWA is a promising candidate for 60 GHz V-band millimeter (mm)-wave applications.

Modeling of a Negative Refractive Index Metamaterial Unit-Cell and Array for Aircraft Surveillance Applications

In this paper, a unique negative refractive index-metamaterial (NRI-MTM) structure is proposed for traffic alert and collision avoidance system (TCAS) for aircraft application. The NRI-MTM unit-cell structure is a combination of square and circular split ring structures. The proposed square and circular split ring metamaterial (SCM) is designed on the top of a 1.6 mm thick FR-4 substrate, with a single circular split ring on the bottom of the substrate. The total dimension of the SCM unit-cell is 23 × 23mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (0.08λ × 0.08 λ), resonating at 1.06 GHz. This unit-cell is further used to create a 5×4 array structure with a dimension of 130 × 111mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (0.46 λ × 0.4 λ). A High-Frequency Structure Simulator (HFSS) is used to assess the electromagnetic properties of the proposed structures. Furthermore, in order to analyse the double negative (DNG) behaviour of the designed SCM structure, the unit-cell is rotated from 0 to 360 degrees with a step of 60 degrees along the azimuthal plane. On doing so, it is observed that, the proposed SCM structures, including unit-cell and array structures, exhibit DNG and NRI properties over the frequency band of 0.5 to 1.2 GHz, thus making it optimum for aircraft surveillance application. The SCM unit-cell and 5 × 4 SCM array structure were fabricated, and the measured results are in well agreement with the simulated results. Further, the array structure is used as a superstrate on the patch antenna to analyze the impact of the MTM on the antenna performance. In comparison to the antenna without the MTM structure, the 5 × 4 SCM array loaded antenna has a gain improvement of 2.8dB and a bandwidth enhancement of 31.5MHz.

Structural changes of a radially symmetric thermocapillary flow in the shallow cavity partially covered by a solid film

This paper presents a numerical study of spatial transformations of a radially symmetric flow in a shallow fluid-filled cylindrical cavity partially covered by a solid non-deformable film. The upper central part of the liquid has a free surface where an intense light beam is focused to produce a hot spot on the symmetry axis. The heating generates a divergent thermocapillary motion on the free surface, which causes the fluid to flow under the immovable solid film. The edge of this film induces thermal perturbations, which, at specific heat generation values, begin to increase and give rise to a gradual radial flow symmetry breakdown that visually demonstrates the onset of vorticity in the azimuthal plane. Three-dimensional calculations have been carried out based on the interfacial hydrodynamics equations using Comsol Multiphysics software. The results of numerical calculations confirm that the instability occurs in the area corresponding to the boundary between the free surface and the solid film. The motion in the azimuthal direction becomes more evident with the growth of heating intensity. The vorticity in the azimuthal plane makes the flow structure significantly more complex compared to the axisymmetric radial flow. Thus, there is a predominantly radial flow in the area of free surface and, at the same time, the vortices with the azimuthal velocity component are observed under the film. As in the experiment, the number of vortices is determined by the ratio of the area of free surface to the covered area. It is shown that the appearance of motion in the azimuthal direction depends on the joint action of several physical mechanisms, which have been initialized in the theoretical model by means of various piecewise thermal and mechanical conditions at the upper boundary.

Design of Broadband Circularly Polarized All-Textile Antenna and Its Conformal Array for Wearable Devices

A broadband circularly polarized (BCP) all-textile antenna and its wearable conformal antenna array (WCAA) are investigated for body-centric communications. Initially, a circularly polarized (CP) microstrip patch antenna loaded with a piece of the modified metasurface is designed to achieve wide impedance and axial ratio (AR) bandwidths. The characteristic mode analysis is employed to understand the operating mechanism, which provides clear physical insight into each mode at various frequencies. Due to the adoption of textile (i.e., felt) as substrate and nylon conductive fabric as conductor, the proposed antenna is flexible, totally conforming to the curve-shaped human body. The antenna with broadside radiation is suitable for off-body communications. For verification, the prototype operating at 5 GHz (5.15–5.825 GHz) band was fabricated. The measured −10 dB impedance and 3 dB AR bandwidths of 35.1% and 17.5% with a peak gain of 8.5 dBi are achieved. Furthermore, the BCP antenna is used as an element to constitute the WCAA, and the omnidirectional radiation pattern in the azimuth plane is achieved for on- and off-body communications. The considerations about how to achieve omnidirectional radiation and avoid radiation nulls are studied in detail. Finally, the WCAA was fabricated and tested; the measured results guarantee its potential for wearable applications.

A Compact, Band-Notched Ultra-Wideband Fully-Recessed Antenna With Pattern Diversity for V2X Communications

In this paper, a compact, band-notched ultra-wideband (UWB) fully-recessed antenna with pattern diversity is proposed and demonstrated for vehicle-to-X communications. The antenna is composed of a multi-port central radiator fully embedded inside a bowl-shaped ground structure with a flush top. The multi-port central radiator consists of a top circular plate, four split-quarter conical monopoles, four vertically-and horizontally-orientated strips, a central metallic cylinder, and a bottom cylinder. Moreover, four F-shaped monopoles are loaded to the multi-port central radiator for producing two narrow notched bands. The integrated antenna achieves a form factor of 0.23λL3, where λL is the free space wavelength at the lowest working frequency. The proposed antenna was fabricated and characterized, achieving a measured S11 < -10 dB band ranging from 1.7 to 6 GHz with two stopbands at around 2.5 and 5.15 GHz for all four ports. Moreover, the measured mutual coupling is smaller than -15 dB, while the envelope correlation coefficients (ECCs) are below 0.1 between different input ports. A vertically-polarized (VP) omni-directional pattern can be supported when all four ports are excited simultaneously, whereas four directional patterns pointing towards different directions in the azimuthal plane can be realized when the four ports are excited individually. The demonstrated antenna is a promising candidate in multiple-input multiple-output communication systems for a wide variety of platforms.

Additively Manufactured Amplitude Tapered Slotted Waveguide Array Antenna With Horn Aperture for 77 GHz

In this work, a combined frontend of horn and slotted waveguide array antenna serving as feeding subsystem is presented. This setup allows to implement an amplitude taper in one plane while using the horn aperture to shape the far field radiation characteristics in the perpendicular plane independently and tailored to the individual demand of the application. Moreover, the feeding system is implemented as a loop resulting in a standing wave distribution for a wide frequency range in order to increase the antenna bandwidth. Two specimens with different horn apertures are additively manufactured in slotted waveguide technology from UV curable photopolymer resin using a digital light processing 3D printer and subsequently metal coated by electroless silver plating. A relatively large bandwidth of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{B}_{-10\text {dB}} = 7.2$ </tex-math></inline-formula> GHz and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{B}_{-15\,\text {dB}}$ </tex-math></inline-formula> of 4.9 GHz is achieved in measurements indicating a relative bandwidth of 9 % and 6 % respectively. Antenna Gain is characterized as 17.5 and 20.17 dBi in measurements while maintaining a sidelobe level of 20–22.5 dB at 77 GHz and exhibiting a radiation efficiency of 78.9 and 79.4 %. The proposed antenna architecture provides a flexible approach for beam shaping in applications where azimuth and elevation planes exhibit different or contrary requirements, e.g. broad vs. narrow field of view - especially suitable for automotive MIMO-radar sensors.

Fast DoA estimation of the signal received by textile wearable antenna array based on ANN model

MLP_DoA module, being an integral part of the smart TWAA DoA subsystem, intended for fast DoA estimation is proposed. Multilayer perceptron network is used to create the MLP_DoA module that provides a radio gateway location in azimuthal plane at its output when a spatial correlation matrix, found by receiving the radio gateway signal using two-element textile wearable antenna array, is on its input. MLP_DoA network training with monitoring the generalization capabilities on the validation set of samples is applied. The accuracy of the proposed modeling approach is compared to the classical approach in MLP_DoA module training previously developed by the authors. Comparison of the presented ANN model with the root MUSIC algorithm in terms of accuracy and program execution time is also done.

A Narrow Beam Steering Antenna Array for Indoor Positioning Systems Based on Wireless Sensor Network

This paper proposes the 2.45 <i>GHz</i> planar Beam Steering Antenna Array for Indoor Positioning Systems. The antenna array consists of a phase shifter based on a 4 &#x00D7; 4 Butler matrix, and an array of four dipole Yagi antennas. By choosing one of four beams using a switching controller, the main beam of the antenna can steer in four directions from +37&#x00B0;, &#x2013;12&#x00B0;, +12&#x00B0; to &#x2013;36&#x00B0;. The antenna has a narrow fan beam with a beamwidth in the azimuth plane of from +21.5&#x00B0; to +24.5&#x00B0; and in the elevation plane of approximately 90&#x00B0; which effectively minimizes multipath signals. These advantages are suitable for positioning systems to increase location accuracy. The antenna achieves a peak gain of from 9.1 to 9.8 <i>dBi</i> in four directions, a wide band of 400 <i>MHz</i>. The fully electronically steerable antenna prototype has been designed using CST software, simulated based on the finite element method, and fabricated on the RO4003C substrate as well as measured. The antenna is implemented in the Indoor Positioning System using three different location methods, including trilateration, triangulation, and fingerprinting, to highlight the antenna&#x2019;s advantages in improving location accuracy with the ratio between the mean location error and area of 0.051, 0.033, and 0.023 respectively.

Determination of Spectral and Broadband Albedos in Visible-near Infrared Bands for Different Phenophases of Wheat Using Hemispherical Directional Reflectance Measurements

Albedo is an important parameter in radiation balance, energy balance, atmospheric correction of remote sensing data and weather forecasting models. The values of albedo of agricultural area vary with changes in biophysical parameters at different phenophases of the crop. Spectral and broadband albedo of visible-infrared bands for wheat canopy was estimated with numerical and spectral integration of hemispherical directional reflectance factors (HDRFs). The HDRF measurements on wheat were acquired at 54 view angles (6 azimuthal planes × 9 view zenith angles) to cover the hemispheric span up to 60° view zenith at 7-8 days’ interval during early growth stages to physiological maturity. Canopy and atmospheric parameters were measured parallel to HDRFs of the crop. The spectral and broadband albedo of wheat varies in decreasing pattern with advancement of growth stages. Visible-infrared albedo of crop was maximum at early growth stages (tillering and booting; 0.23) and minimum at late growth stages (late milking and dough; 0.15). The albedo values retrieved from HDRF in this investigation can be useful for phenophase specific applications in cropland fluxes algorithms, crop phenotyping, regional climate modeling and other remote sensing studies.

Reduction of side lobes in the entire azimuth plane in a planar elliptical array antenna

SummaryA novel synthesis method to reduce the maximum side lobe in the entire azimuth plane and for achieving a desired value of directivity of a concentric elliptical array antenna is addressed in this paper. Three well‐performing meta‐heuristic optimization algorithms, teaching learning‐based optimization (TLBO), symbiotic organism search (SOS), and quantum particle swarm optimization (QPSO), are employed to optimize the cost function and to obtain the desired radiation pattern. Different simulation‐based experiments are performed to obtain the best possible set of angular positions and the distribution of isotropic antennas across the ellipses by rigorously maintaining non‐overlapping constraints. The major benefit of the proposed design is the deprecation of interference in all phi planes. The statistical analysis of the simulation results demonstrate perceptible improvement compared with that of a uniformly spaced concentric elliptical array and hence show the efficiency of the proposed algorithms. In both simulation studies, the results obtained using TLBO, SOS, and QPSO are compared. Analysis of the results exhibits that for the stated objective, the TLBO‐ and SOS‐based side lobe reduction approach performs superior to QPSO method. Proposed multi‐objective research work could lead to reduce payload and can simultaneously achieve isoflux coverage in entire azimuth plane on the earth surface which can essentially be utilized in (Low Earth Orbit) LEO and (Geostationary Earth Orbit) GEO satellites applications.

Orthotropic anisotropy analysis and parameter estimation from 3-D vertical seismic profile data

SUMMARY Orthotropic velocity models are commonly considered as to have the lowest complexity (or highest symmetry) that can realistically describe the combined effect of Earth’s velocity heterogeneity in the vertical and in the horizontal (radial) directions. Velocity heterogeneity in the vertical direction is commonly caused by horizontal stratification of subsurface rock layers with different elastic properties or caused intrinsically by microlayered rocks such as shales. In the horizontal direction, azimuthal variation of the Earth’s stress field can initially lead to preferential deformation of pore space in the rocks and eventual development of aligned (vertical) fractures that are commonly regarded as the main cause for seismic azimuthal anisotropy. Building an appropriate orthotropic velocity model that can explain seismic velocity variations in vertical planes and along any azimuthal direction can therefore enhance the quality of seismic data processing and imaging. This, however, requires knowledge of several anisotropy parameters defined in the three symmetry planes of the orthotropic model and also the orientation of these planes. A combination of P- and S-wave slowness and polarization data derived from vertical seismic profile (VSP) measurements has been routinely used to estimate parameters of less complex anisotropic media such as transverse isotropy with vertical axes of symmetry (VTI). The accuracy of anisotropy parameter estimation by these methods depends primarily on the availability of data that are used in the inversion and the size of anisotropy parameters. In this study, we develop a benchmark for the accuracy of orthotropic parameters that are estimated from 3-D VSP measurements using P-wave slowness only method. Through numerical analysis, we model a wide range of fracture-induced orthotropic symmetries by adding vertical fractures to a background VTI media and show that the accuracy of our orthotropic parameter estimation method is dependent on anisotropy in the host media, intensity of fracturing, noise level in slowness data and slowness data coverage in both the dip and azimuthal planes. We then expand our accuracy analysis work to multilayer media by examining the accuracy of P-wave slowness method for orthotropic anisotropy parameter estimation by inverting finite-difference data generated in a pseudo 3-D VSP experiment. We show that, for a typical 3-D VSP experiment, reasonable estimates of orthotropic parameters in the model can only be obtained with slowness data taken from Xmax/Z ≥ 1 and line azimuth interval ϕ ≤ 10° where Xmax is the maximum source to receiver offset and Z is the receiver depth. We finally describe how field VSP measurements can be inverted for orthotropic anisotropy parameters.

Metamaterial-Inspired Flat Beamsteering Antenna for 5G Base Stations at 3.6 GHz.

In this paper, a metamaterial-inspired flat beamsteering antenna for 5G applications is presented. The antenna, designed to operate in the 3.6 GHz at 5G frequency bands, presents an unique flat form factor which allows easy deployment and low visual impact in 5G dense scenarios. The antenna presents a multi-layer structure where a metamaterial inspired transmitarray enables the two-dimensional (2D) beamsteering, and an array of microstrip patch antennas is used as RF source. The use of metamaterials in antenna beamsteering allows the reduction of costly and complex phase-shifter networks by using discrete capacitor diodes to control the transmission phase-shifting and subsequently, the direction of the steering. According to simulations, the proposed antenna presents steering range up to , achievable in both elevation and azimuth planes, independently. To prove the concept, a prototype of the antenna has been built and experimentally characterised inside an anechoic chamber. Although constructed in a different substrate (FR4 substrate) as initially designed, beamsteering ranges up to in azimuth and in elevation, limited to the proposed case-studies, are reported with the prototype, validating the antenna and the usefulness of the proposed design.

28 GHz circular polarized fan‐out antenna array with wide‐angle beam‐steering

The article presents 28 GHz circular polarized antenna arrays designed in an embedded wafer level ball grid array (eWLB) package for 5G applications. The antenna arrays are realized on a re-distribution layer (RDL) in the fan-out region of the chip package. Two separate but identical arrays perform RX and TX operations where a crossed dipole is used as a building block of the array. These 4-element arrays have <−10 dB impedance bandwidth covering 25.3–29.8 GHz (4.5 GHz bandwidth) while presenting 10 dBi maximum realized gain. The measurement results show <3 dB axial ratio in the band 26–29.5 GHz, and the main beam can be steered in ± 50 ∘ in the azimuth plane when array elements are fed by appropriate phases from the chip. The radio frequency module provides 31 dBm maximum equivalent isotropic radiated power (EIRP).

Broadband Dual-Polarized Antenna Array With Endfire Radiation for 5G Mobile Phone Applications

This letter presents a wideband compact dual-polarized antenna with endfire radiation pattern for the fifth-generation millimeter-wave (mm-wave) applications. The antenna achieves a –10 dB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> bandwidth of 16.5% (25–29.5 GHz). The antenna has a thickness of 1.6 mm and a clearance of 3.4 mm. The presented four-element array achieves a maximum realized gain of 9.9 and 9.1 dBi for horizontal mode (H-mode) and vertical mode (V-mode), respectively. The antenna has a wide beamwidth in both elevation and azimuth planes with good scanning performance for both H-mode and V-mode.