Antenna Array Elements Research Articles

Gain Improvement of Millimetre-Wave Two Element Array Antenna for 5G Networks by Using Frequency-Selective Surface-based Reflector

Gain Improvement of Millimetre-Wave Two Element Array Antenna for 5G Networks by Using Frequency-Selective Surface-based Reflector

Plasmonic antennas based on rectangular graphene nanoribbons with controlled polarization of terahertz and infrared radiation

Background. To develop new terahertz wireless communication systems with high throughput and transmission speeds, such as 6G and above, effective control of the polarization direction of emitted terahertz waves is necessary, but most methods are technologically complex and expensive. The implementation of terahertz antennas and devices based on 2D materials such as graphene solves the problem associated with developing effective control. Aim. Study of the possibility of controlling the polarization of terahertz and IR radiation of plasmonic antennas based on rectangular graphene nanoribbons by changing the chemical potential (application of an external electric field). Methods. This important scientific problem related to the design of terahertz antennas can largely be solved by simulation using the electrodynamic simulation program CST MWS 2023. Results. Plasmon terahertz antennas based on rectangular graphene nanoribbons were chosen as the object of analysis and the possibility of emitting waves of two orthogonal polarizations was shown. Methods have been identified for controlling the polarization of terahertz and IR radiation from such antennas, based on the selection of operating frequencies corresponding to the resonances of the modes of surface plasmon-polaritons, and the application of metallization to the dielectric substrate. Conclusion. The ability to control the polarization of terahertz and IR radiation makes it possible to create both new elements of plasmonic antenna arrays and new communication technologies, including future 6G networks.

4 × 4 graphene nano-antenna array for plasmonic sensing applications

The manuscript presents the design and investigation of square and L-shaped graphene plasmonic nano-antenna arrays on a silicon dioxide substrate for plasmonic biosensing applications. The design parameters, such as the shape of the nanostructure, spacing between the antenna array elements, size of the antenna array and chemical potential of the graphene are used to analyze the plasmonic resonance characteristics of the proposed plasmonic nano-antenna array. Initially, dispersive characteristics of graphene, such as conductivity, permittivity and refractive index are analyzed using its chemical potential for the validation of the graphene material for plasmonic sensing applications. The proposed square and L-shaped nanopatch antenna structures are radiating at 30 THz with a reflection coefficient of -28.4 dB and − 44.6 dB respectively at 0.1 eV chemical potential. It is observed that graphene nanopatch antenna radiates at 30 THz, 115 THz and 176 THz at a chemical potential of 1.3 eV. Further, the study demonstrated that the designed square and L-shaped nano-antenna exhibit a gain of 3.52 dB and 9.51 dB respectively at 30 THz. The gain can be increased further using a square and L-shaped nano-antenna array of dimensions 2 × 2, 3 × 3 and 4 × 4. It is observed that maximum gains of 33.44 dB and 30.86 dB are obtained for the square and L-shaped 4 × 4 plasmonic nanoarray antenna respectively. Finally, a nanocircuit model of square and L-shaped nano-antennas is proposed and validated through CST simulations.

Analyzing the trade-offs: non-identical antenna array elements in wireless communication systems

Analyzing the trade-offs: non-identical antenna array elements in wireless communication systems

Design of Asymmetric Metamaterial 8-Circular Element Array Antenna for 5G MIMO Applications

Design of Asymmetric Metamaterial 8-Circular Element Array Antenna for 5G MIMO Applications

Malfunctioning conformal phased array: Radiation pattern recovery with particle swarm optimisation

AbstractThe electronic beam steering in conformal phased arrays is formed by exciting the multiple antennas with appropriate phase shifts. However, the malfunctioning of phase shifters connected to the central antenna elements in the conformal array distorts the radiation pattern of the array system severely as compared to edge elements resulting in the reduction of the array gain and increase in the side lobe levels. Here, the authors propose a non‐dominated sorting multi‐objective particle swarm optimisation (NS‐MOPSO) technique capable of recalculating the independent phases of working antenna elements in the array in such a manner as to correct the overall radiation pattern. To illustrate the radiation pattern's recovery capabilities of the optimisation technique in case of malfunctioning of any random phase shifter(s), a 1 x 7 microstrip patch antenna array operating at 2.45 GHz on a wedge‐shaped conformal structure was designed in CST simulator. To test, the radiation pattern's recovery capabilities of the NS‐MOPSO approach, phase shifters connected to the antenna elements in the array were made to malfunction. Then the optimisation algorithm recalculates the phases for individual antenna elements to achieve the desired corrected radiation pattern. The simulated and measured radiation pattern recovery results are in good agreement with each other.

A Symmetrical 32 × 1 and 16 × 1 Elements Antenna Array Failure Correction with Nulls Using Brain Storm Optimization

A Symmetrical 32 × 1 and 16 × 1 Elements Antenna Array Failure Correction with Nulls Using Brain Storm Optimization

Low-Profile Differentially-Fed Tightly-Coupled Dipole Array

Introduction. Tightly coupled dipoles currently belong to one of the most popular types of antenna arrays. Their main advantages include an electrically low-profile height, the ability to scan the beam across a wide sector of angles without the onset of scan blindness, and a low level of cross-polarization. In recent years, the number of publications on the topic of antenna arrays of this type has increased significantly. The authors have paid sufficient attention to baluns included in the antenna array elements. However, the possibility of implementing a differentially-fed scheme in antenna arrays of this type remains poorly studied. This makes the study of this subject especially relevant in the development of radio devices where such feed technique is preferable.Aim. Differentially-fed tightly-coupled dipole array design and study.Materials and methods. The following materials were used to create the prototype: copper sheet, ceramic glass substrate ST-50-1, dielectric RO3003. A numerical study of the characteristics was carried out in the ANSYS HFSS environment; an experimental study of the prototype was carried out in an anechoic chamber using an automated measuring complex and a vector network analyzer.Results. The results of designing a planar antenna array of tightly-coupled dipoles for the X-band are presented. In the antenna array, each of the dipole arms is fed using a separate coaxial cable, while the two arms of one dipole are fed out-of-phase. The results of a numerical study of the characteristics of an 8 × 8 antenna array made from the developed elements are presented. Across the range from 6.5 to 12.25 GHz, the average active VSWR does not exceed 3, while the gain varies from 21.5 to 25.7 dBi. The possibility of beam scanning in a sector of angles up to ±45° is shown. The results of an experimental study of the radiation characteristics and matching of the prototype of a single element are presented.Conclusion. The importance of taking into account the effects that arise at the edges of finite antenna arrays during simulations is shown. The feasibility of manufacturing and measuring antenna array prototypes with a large number of elements is experimentally confirmed. The proposed element design demonstrates the possibility of implementing the differentially-fed scheme in tightly coupled antenna arrays.

Wideband, Dual-Polarized Patch Antenna Array Fed by Novel, Differentially Fed Structure

In this article, a 1 × 4 wideband, dual-polarized patch antenna array fed by a novel, differentially fed structure is proposed. The differentially fed structure of the antenna was realized by a parallel line structure that was printed on a PCB and connected with the inner and outer conductors of a coaxial cable. This method elaborately solved the problem of the narrow bandwidth of conventional microstrip differential feeding. By using a relatively thick air substrate (thickness = 0.19 λ0), stacked patches, a coupling feeding structure, and a differential feeding structure with the novel design, the element of the patch antenna array introduced below operated from 0.415 GHz to 0.707 GHz (achieving the 52.0% bandwidth) with a VSWR < 2.0, yielding a high port isolation less than −28 dB. For the array, an active VSWR less than 2.0 was also obtained with a port isolation of less than −25 dB, ranging from 0.405 GHz to 0.696 GHz. In the desired bandwidth, the array had an azimuth 3 dB beamwidth of about 19° for both horizontal polarization and vertical polarization. The antenna array also had good performance in scanning (stable gain and 3 dB beamwidth) and circular polarization (a 3 dB axial ratio bandwidth better than 54.5%).

Electrodynamic modeling of a four-channel antenna with an operating frequency band of octave

The actual problem of electrodynamic modeling of a four-channel antenna with an octave operating frequency range has been considered. The results of numerical electrodynamic modeling of a four-channel antenna have been presented. The considered antenna with an octave operating frequency range is a rectangular curtain comprising four independent non-equidistant channels. Numerical electrodynamic modeling of a four-channel antenna has been carried out in the ANSYS HFSS software package, with the convergence parameter DeltaS = 0.01. As a result of the simulation, the frequency characteristics of each channel have been obtained: VSWR, gain, reflection coefficient, directional pattern. The antenna provides a scanning angle as part of an ultra-wideband digital antenna array of at least ±30° in azimuth and from 0° to 60° in elevation. The gain of the antenna channels in the operating frequency range is not lower than 6 dB. According to the simulation results, the VSWR of each channel of the antenna in the operating frequency range does not exceed 2.55. To minimize the influence of mutual coupling of channels on the antenna characteristics, the distance from the phase centers of the curtain emitters to other elements of the ultra-wideband digital antenna array should be at least a wavelength in free space at the lower frequency of the operating frequency range. It has been shown that the considered four-channel antenna provides an octave operating frequency band and can be used as part of an ultra-wideband digital antenna array for direction finding of radiation sources.

Terahertz phased array antenna based on integrated taper emitters

We report on an all-dielectric integrated taper as a radiating element for terahertz phased array antenna. The taper was manufactured on the base of the silicon substrate and was integrated with effective-medium waveguide. The obtained value of return loss of the taper emitter is 12.9 dB at a radiation frequency of 145.5 GHz. The width of the radiation pattern is 56.2° in the plane of the substrate. To demonstrate the change of the radiation pattern at different values of the phase difference between the elements of the phased array antenna, an appropriate simulation was carried out. It was found that with a phase difference between each pair of adjacent elements of a phased array antenna of 60°, the direction angle of the mainlobe of the radiation pattern changes by 5.5°. A proof of concept experimental demonstration of scanning by the mainlobe of the radiation pattern of a terahertz phased array antenna was carried out. The obtained results open up the possibility of use of the proposed taper emitter in future phased array antennas as part of a new generation communication system with ultra-high data transfer rate.

Method of characteristic modes

In recent years, the number of works on the method of characteristic modes and problems solved with its help has increased significantly, which indicates an awareness of its potential and, in connection with this, a growing interest in this approach. The attractiveness of this method lies in the fact that it provides a clear physical picture of the occurring phenomena and the ensuing opportunity to build on this basis methods for creating structures with the required parameters and combating undesirable phenomena. Unfortunately, in the Russian-speaking segment of applied electrodynamics, very few researchers are engaged in the development and application of the approach under consideration. The purpose of this work is to increase the interest of Russian-speaking researchers in the method of characteristic modes. A review of publications devoted to the method of characteristic modes, both early, fundamental and already classic, associated with the names of R.J. Garbacz and R.F. Harrington, and those which have appeared in recent years and offer generalizations of the method for various electrodynamic structures, has been carried out. This includes composite structures consisting of a set of metal and dielectric bodies of various configurations. In addition, variants of the method for antenna arrays of both infinite periodic and finite sizes have been considered. Issues related to modal tracking problems, orthogonal properties of characteristic modes and improving the convergence of solutions have been considered. Much attention is paid to works containing solutions to specific practical electrodynamic problems using the method of characteristic modes. The works have been shown, in which simple and effective approaches based on the method of characteristic modes are given for the design of a ship's HF antenna system, on-board aircraft antennas in the short-wave region, antennas placed on the platform of a battle tank, and the concept of designing an antenna for an electrically small-unmanned aerial vehicle has been presented. Options for solving the problem of reducing the mutual coupling of elements in antenna arrays have been shown. Attention is paid to MIMO antennas, antennas for smartphones, systems with specified radiation zeros, antennas using metasurfaces. According to the authors, the characteristic mode method, taking into account the increasing possibilities of its application, will make it possible to take the next step in the development, analysis or synthesis of new antenna structures that meet ever-increasing modern requirements.

Adaptive Beamforming Based on Artificial Neural Networks

Adaptive beamforming is technique of signal processing play important role to increasing capacity of the wireless communication and radar systems by configured the steerable of radiation pattern and maximize gain and directivity in a direction of arrival (DoA) of desired users in order to minimizing side lobe and reducing signal to interference. We review recently the classic technique of adaptive algorithms; we specified tow method for this preprocessing beam former LMS and RLS. The least Mean Square (LMS) operate the weight vectors of antenna array elements for beamforming by iterative process as well need to be continuously adapted to the ever-changing environment. Moreover recursive least square (RLS) give advantage for fast convergence beamforming. In this paper we proved the performance of this algorithms by updating the weights in addition process based on estimated vectors using neural network, The first phase for smart beam former are used by direction of arrival (DoA) estimated using radial basis neural network (RBFNN). In next step the targets is generated from the optimum weight calculated using Minimum Variance Distortion less method (MVDLM). Finally, the simulation result for the new process is synthetized and shows using Matlab application.

Investigation of mutual coupling coefficients in dual-polarized antenna arrays

Background. Antenna arrays are widely used in various fields of radio engineering, such as radio and telecommunications, satellite communication systems, etc. One of the important characteristics of an antenna array is its radiation pattern. The estimation of impedance matrices, scattering matrices, and partial radiation patterns is usually performed based on the results of numerical electrodynamic modelling. In the case of a large number of antenna elements, such modelling and optimization of the array requires significant time.
 Aim. To investigate the mutual coupling between dual- polarised antenna elements included in a linear antenna array.
 Methods. Modelling of antenna arrays based on cross-dipole elements was performed using methods of electrodynamic modelling software. The study of the mutual coupling of antenna elements in the antenna array and verification of the developed mathematical model were carried out by numerical methods.
 Results. A physical interpretation of that there is no almost interaction between the elements operating in orthogonal polarizations, and the coefficients of mutual coupling decrease with increasing distance between antenna elements is given. Proposed a simplified model of mutual coupling, which reduces the computational complexity of the problem of determining the mutual coupling matrices.
 Conclusion. It is developed a mathematical technique that allows to calculate the characteristics of antenna arrays with a large number of antenna elements, meanwhile electrodynamic modelling is carried out only for an isolated antenna element and a two-element array.

Design of a Ka-Band Heterogeneous Integrated T/R Module of Phased Array Antenna

The central element of a phased array antenna that performs beam electrical scanning, as well as signal transmission and reception, is the transceiver (T/R) module. Higher standards have been set for the integration, volume, power consumption, stability, and environmental adaptability of T/R modules due to the increased operating frequency of phased array antennas, the variability of application platforms, and the diversified development of system functions. Device-based multichannel T/R modules are the key to realizing low-profile Ka-band phased array antenna microsystem architecture. The design and implementation of a low-profile, high-performance, and highly integrated Ka-band phased array antenna T/R module are examined in this paper. Additionally, a dependable Ka-band four-channel T/R module based on Si/GaAs/Low Temperature Co-fired Ceramic (LTCC), applying multi-material heterogeneous integration architecture, is proposed and fabricated. The chip architecture, transceiver link, LTCC substrates, interconnect interface, and packaging are all taken into consideration when designing the T/R module. When compared to a standard phased array antenna, the module’s profile shrunk from 40 mm to 8 mm, and its overall dimensions are only 10.8 mm × 10 mm × 3 mm. It weighs 1 g, and with the same specs, the single channel volume was reduced by 95%. The T/R module has an output power of ≥26 dBm for single-channel transmission, an efficiency of ≥25%, and a noise factor of ≤4.4 dB. When compared to T/R modules based on System-on-Chip (SOC) devices, the RF performance has significantly improved, as seen by an increase in single channel output power and a decrease in the receiving noise factor. This work lays a foundation for the devitalization and engineering application of T/R modules in highly reliable application scenarios.

Dielectric Lens Antenna for Industrial Radar Applications

Industrial radar applications like tank level measurement is an important research and application area in radar technology. Radar level measurement is a safe solution even under extreme process conditions (pressure, temperature) and vapors. Special antennas are required to meet electromagnetic requirements such as high gain, low sidelobe level and high bandwidth. The small side-beam level and narrow main beam primarily minimize reflections from the side of the tank, while the bandwidth determines the distance resolution of the measurement system. Another requirement is a small size and good manufacturability of the antenna. The main promising solutions are the use of microstrip, horn or dielectric lens antennas for tank level measurement systems. After several tests, we have concluded that the optimal choice for tank level radar measurement task, in terms of integrability and antenna parameters, is a dielectric antenna. The dielectric antenna has many other applications in modern mobile systems as 5 and 6 G systems where these antennas are elements of antenna arrays of beamforming or MIMO systems. In this paper, a special dielectric lens antenna is presented, satisfying main requirements, namely a circular antenna cross section, high antenna aperture efficiency and low sidelobe level. The center frequency of the antenna is 26 GHz with a band width of 1 GHz. The paper presents the analytic investigation and design of the dielectric lens antenna and the circular wave guide transition in detail. The electromagnetic design of the antenna was carried out using CST Microwave Studio 3D software.

A Decoupling Technique for Beamforming Antenna Arrays Using Simple Guard Trace Structures

This paper discusses decoupling techniques for suppressing electromagnetic coupling between elements of beamforming antenna arrays. Guard trace structures, which are commonly used for crosstalk reduction on printed circuit board technology, are proposed to be inserted between the array elements for coupling reduction. Two types of guard trace structures, i.e., straight guard traces and serpentine guard traces, were explored, and the effect of using via holes on both types of guard traces was studied. For this purpose, two-element antenna arrays with guard trace structures inserted between array elements were designed and simulated. The simulation results showed that a straight guard trace with vias (straight GTV) and a serpentine guard trace without vias (serpentine GT) could effectively reduce EM coupling between elements of array antennas. To verify the simulation results, prototypes of antenna arrays with straight GTV and serpentine GT were realized and measured. The measurement results showed coupling reductions of 5 dB and 6.4 dB could be achieved when straight GTV and serpentine GT are inserted between two array elements separated by edge-to-edge distances of 4 mm and 9.05 mm, respectively. Therefore, the proposed decoupling technique is suitable for beamforming antenna arrays with a very close distance between array elements.

Design of a compact filter integrated wideband and circularly polarized antenna array for K-band application

A compact filtering mechanism in the antenna system is required to avoid unwanted incoming electromagnetic waves in the working frequency band. A circularly polarized (CP), wideband, and high gain antenna array co-design with a wide bandpass filter (BPF) for a K-band satellite application at (17.7 to 21.2) GHz is studied in this paper. Antenna array elements with diagonal slots and BPF in the same frequency are compatible. For maximum radiation efficiency, the input impedance of the slotted 16 × 16 elements antenna array is matched to 50 Ω and equal to the output impedance of the BPF in the operating band. To implement the filtering concept, a co-design is modeled and simulated. The suggested wideband BPF and antenna array are integrated on a combined aperture, manufactured, and tested experimentally. Based on the results of the tests, it can be concluded that the suggested filtering antenna array is well matched (|S11| < −15 dB) throughout a wide frequency band of 17.7 GHz to 21.2 GHz. The final structure simulated and measured 3 dB axial ratio covers the functional spectrum with a maximum 25.3 dBi gain. High directive beams with a 20 dB cross-polarization suppression level in E & H planes are simulated and measured. Due to these advantages, the suggested antenna is an attractive option for use in K-band 3U satellite applications to minimize the requirement for extra filtering circuits in the RF system.

An efficient reconfigurable optimal source detection and beam allocation algorithm for signal subspace factorization

&lt;span lang="EN-US"&gt;Now a &lt;span&gt;days, huge amount of data is communicated through channels in wireless network. It requires an efficient parallel operation for the optimal utilization of frequency, time allocation and coding model for signal subspace factorization in smart antenna. In view of this requirement, an efficient reconfigurable optimal source detection and beam allocation algorithm (RoSDBA) is proposed. The proposed algorithm is able to allocate desired signal to the user space to reduce the noise and also for efficient allocation of subspace to remove disturbance in all directions. The proposed method efficiently utilizes the antenna array elements by accurate identification and allocation of antenna array elements such as individual radiators, radiation beam, signal strength, and disturbance factor. With respect to simulation analysis, the proposed method shows better performance for the resolution, radiation beam allocations, identification bias, distribution factor and time taken for the detection of various&lt;/span&gt; array arrangements and source numbers.&lt;/span&gt;

Rainbow link beamforming technology and relevant analysis

In the 5G era, millimeter wave has been mentioned as an important position. Millimeter wave has some problems that cannot be ignored: the free space path loss and atmospheric attenuation. To overcome these problems, millimeter wave systems rely on beamforming to overcome losses. Traditional techniques utilize phase antenna arrays for beamforming, which can cause delays in the time consumption and beam scheduling, and due to limited beams, this technology can only be connected to a limited number of devices, and each transmission occupies the entire bandwidth. This paper introduces a new technology called rainbow link, which is implemented by a new true time delay (TTD) array structure. This technology can achieve the allocation of different subcarriers to a large number of users in the corresponding beamforming direction. Users only need to select appropriate frequency resources. In this work, we calculate the performance of rainbow link with different parameters, and our results show that given 1 GHz bandwidth using 64 element antenna arrays, a rainbow-link cell achieves 1ms latency and 0.6M symbols per second with 0.03 active user rate.