Linear Antenna Array Research Articles

Synthesis of Unequally Spaced Linear Antenna Array for Subsidiary Maxima Elimination Using LGChOA Algorithm

Synthesis of Unequally Spaced Linear Antenna Array for Subsidiary Maxima Elimination Using LGChOA Algorithm

Investigation and Implementation of Miniaturized Microwave System for Linear Array Antenna Loaded With Omega Structures Planar Array

Investigation and Implementation of Miniaturized Microwave System for Linear Array Antenna Loaded With Omega Structures Planar Array

Design of Antipodal Vivaldi Antenna for Medical Imaging Application

The microwave imaging (MWI) system in medical applications is commonly used to detect abnormalities in the human body. The purpose of this study was to design an Antipodal Vivaldi Antenna (AVA) for medical imaging applications using MWI. The research method used is based on the AVA design simulation of the CST Studio Suite 2019 application using time and frequency domain methods, which has dimensions of 60x40 mm2 with an antenna structure that works in the frequency range of 6.3-9.6 GHz, the impedance for bandwidth is -10 dB, using Flame Retardant-4 (FR-4) thickness 1.6 mm (= 4.3, tan δ = 0.025) as substrate material. A linear array of antennas was utilized in the simulation, either with or without a phantom. The phantom options include an absence of a phantom (only antennas), a cube-shaped water phantom, and a water phantom containing an anomaly. The result of the simulation on the AVA design produces a bandwidth of 41.61%, a gain of 5.16 dB, a return loss of -26.73 dB, a Specific Absorption Rate (SAR) value of 0.26 W/kg and a graph of S-parameters (S21). It can be concluded that the MWI system using the AVA design in this study has the potential to properly detect the presence of anomalies.

МАТЕМАТИЧНА МОДЕЛЬ ДОСЛІДЖЕННЯ КОЕФІЦІЄНТІВ ВІДБИТТЯ ВІД РУПОРНИХ ВИПРОМІНЮВАЧІВ ФАЗОВАНИХ АНТЕННИХ РЕШІТОК

The article is devoted to the problem of researching reflection coefficients from horn emitters that are part of a phased antenna array. It was found that the advantage of using horn antennas is the high directivity of their radiation, a significant efficiency and a fairly high amplification factor. However, their main drawback is the back radiation (scattering) of electromagnetic waves by the elements of the antenna design. This affects the radar visibility of samples of weapons and military equipment and their electromagnetic compatibility. To eliminate these shortcomings, the article analyzes the differential characteristics of the backscatter diagrams of aperture antennas in order to improve the mathematical model of the reradiated field study, taking into account the reflection coefficients from horn emitters. In the course of the study, the causes and regularities of such a phenomenon as the reflection of electromagnetic waves from internal inhomogeneities of horn antennas were clarified, in order to reduce it. The given graphs of the dependence of the amplitudes of the reflected electromagnetic field on the observation angles show that the improvement of the alignment in the antenna path will cause an increase in the maximum signal amplitude in the transmission mode. According to the principle of inversion of antennas, such an arrangement will improve the absorption of waves of higher types directed to the openings of a single emitter or an equidistant antenna array. This will reduce the voltage standing wave factor and the level of side lobes. Therefore, the sounding radar station will receive a reduced level of the reflected signal, which will improve the defense of weapons samples that include a horn as a separate antenna or as part of equidistant linear phased antenna arrays. Keywords: phased antenna array; pyramidal horn emitter; reduction of the effective scattering surface; reflection coefficient.

Low SLL enhanced gain proximity coupled linear antenna array for 5G wireless communications

This manuscript presents a proximity-fed linear seven-element array antenna with significantly suppressed cross-polarization level for fifth generation (5G) wireless communications. The proposed structure uses a Chebyshev form of power distribution to couple the non-uniform radiating elements. Generally, a conventional series-fed array with identical and similar number of elements provides a minimum sidelobe level (SLL) of 13.5 dB and a gain up to 14.51 dBi (maximum). However, the proposed array provides SLL lower than −21.11 dB and a gain of 15.54 dBi at 28 GHz. Moreover, measured cross-pol discrimination is observed to be greater than 36 dB in elevation plane and in the azimuth plane as well. The proposed antenna array includes seven rectangular patches of varying widths on the upper substrate and is fed through proximity coupling using slit-loaded segmented feed lines on the lower substrate. The developed array antenna exhibits a 5.82 % fractional bandwidth from 26.52 to 28.11 GHz with a radiation efficiency of 91 %. Experimental and simulation results of vital antenna parameters are in close agreement. The overall radiation behavior of the proposed antenna array is found to be superior when compared with the other state of the art approaches, as shown in a comprehensive comparison table.

Linear antenna array modeling with deep neural networks

In modern wireless telecommunication systems, antenna arrays are widely used as elements of multiple – input multiple – output technology. In the fifth-generation systems, arrays are utilized to realize beamforming that forms the radiation pattern of the base station in the direction of the mobile user. This requires the utilization of many-element antenna arrays that are precisely controlled to achieve the required radiation properties. In this paper we apply the concept of deep neural network to model antenna array radiation properties. In this proof-of-concept research we aim at investigating to what extent it is possible to use deep neural networks for modeling antenna arrays. We consider a full-wave model of linear array with a reflector, which was controlled by the phase and amplitude of the signals feeding the elementary radiators. The applied method made it possible to solve the direct and inverse problems. The results that we obtained show that deep neural networks are able to model antenna array properties.

An efficient linear and elliptical antenna array design using sail fish optimization

Abstract This article introduces an innovative approach to antenna array design, focusing on synthesizing the optimal radiation pattern for fifth-generation (5G) communication. The authors have designed a reliable linear and elliptical antenna array (EEA) of dipole elements by employing sailfish optimization (SFO). 5G technology promises transformative improvements in wireless communication with high data rates, expanded capacity, minimal latency, and exceptional service quality. The crux of 5G lies in the precision of antenna array design, aiming for an emission pattern with minimal side lobe levels (SLLs) and a narrow half-power beam width (HPBW). A narrower HPBW is essential for efficient long-range communication, whereas reducing the SLLs enhances signal clarity. The SFO optimizes the current excitation of each antenna element for reducing the mutual coupling effects and lowering the SLL and HPBW values in linear and EEAs. This paper uses the exact excitation to each element to show the linear antenna arrays (LAA) (10-, 16-element) design examples and EAA (8-, 12-, 20-element) structures. The LAA and EAA design examples obtained with the SFO algorithm establish the advancement in SLL suppression over the uniform antenna array and the methods proclaimed in the recent article.

A Combined Electronic Position- and Partial Amplitude-Control Synthesis Technique for Sidelobe Reductions in Linear Array Antennas

A Combined Electronic Position- and Partial Amplitude-Control Synthesis Technique for Sidelobe Reductions in Linear Array Antennas

LMS and RLS beamforming algorithms based linear antenna array with known mutual coupling

This study explores the application of LMS and RLS algorithms in adaptive beamforming for a linear array of half wavelength dipole (HWD) antennas with known mutual coupling. The research initiates by deriving analytical expressions for the covariance matrix of signal impinging on an HWD antenna array, accounting for mutual coupling effects. Leveraging these expressions, we calculate the weights for both LMS and RLS algorithms, enabling the evaluation of the overall far-field radiation patterns of the HWD antenna array. The results demonstrate that these algorithms effectively steer the main lobe of the radiation pattern towards the desired user while creating nulls in the direction of undesired users. Notably, simulations indicate that the proposed compensation method enhances the performance of beamforming algorithms, particularly when considering mutual coupling effects. Specifically, the LMS algorithm outperforms the RLS algorithm in reducing interference, resulting in lower side lobe levels (SLL) in the radiation pattern.

Dual Band 1x4 Linear Metamaterial Bowtie Antenna Array for Autonomous Vehicle in Public Safety Band Communications

This research presents the design, simulation, and fabrication of a dual-band 1x4 linear metamaterial bowtie antenna array for applications in 5G wireless systems and public safety band communications. The single-element antenna is a compact dual-band structure with a complementary split-ring resonator (TCSRR) element, and it exhibits resonant frequencies of 3.5 GHz and 4.9 GHz, covering the sub-6GHz 5G spectrum and the public safety band. The antenna aray design is optimized for impedance matching and radiation efficiency. The 1x4 linear antenna array is designed with a quarter-wave transformer feed network and carefully controlled mutual coupling to enhance gain and directionality. Simulated and measured results confirm the performance of the array, with a reflection coefficient within -10 dB from 3.2 GHz to 3.85 GHz and from 4.55 GHz to 5.95 GHz and 3.45 GHz to 3.75 GHz and 4.45 GHz to 5.7 GHz, respectively. The array exhibits a peak realized gain of up to 8.7 dBi and efficient radiation patterns. This work offers promising insights into the development of antenna systems for advanced wireless communication applications and vehicle-to-vehicle communication in public safety band.

Design and Analysis of Microstrip Patch Antenna Array and Electronic Beam Steering Linear Phased Antenna Array with High Directivity for Space Applications.

This study proposes an E-shaped microstrip patch antenna array (MSPAA). The substrate is RT/Duroid5880. Its 2.2 dielectric constant gives it a larger bandwidth than substrate materials with higher dielectric constants. The periphery dimension of a single E patch is 50 × 41 mm2. The areas of 2 × 2 and 3 × 3 MSPAAs are 120 × 96 and 180 × 144 mm2, respectively. Array members are 10 and 7 mm apart horizontally and vertically, respectively. MTM technology builds the projected MSPAA. This work looks at the effects of gain, reflection coefficient (return loss), directivity, bandwidth, and VSWR on proposed 2 × 2 and 3 × 3 MSPAAs with different patch lengths of 30, 40, and 60 mm, patch widths of 40, 50, and 60 mm, and substrate thicknesses of 0.8 and 1.6 mm. Also, this study compares the performance of existing E-shaped MSPAAs with proposed 2 × 2 and 3 × 3 MSPAAs. The suggested MSPAA performs better than the existing E-shaped MSPAA. The series network analyzer measures the prototype MSPAA's experimental outcomes. The polynomial is recommended for estimating the antenna array area with odd and even rows and columns. CST Studio Suite software analyzes and designs antenna arrays, and simulation findings are compared with hardware results. The main benefit of the proposed 2 × 2 MSPAA is that it reduces sidelobes. It has a gain of 8.9 dBi, a directivity of 8.95 dBi, a VSWR of 1.02, a return loss of -32.91 dB, and a bandwidth of 0.1 GHz at both 1.6 and 0.8 mm substrate material thicknesses. Across its operating range of 3.8-4.2 GHz, the recommended array antenna has a radiation gain of 7.01-7.81 dB and an efficiency of 68.51-71.11%. At 4 GHz, this study looks at how electronic steering affects the phase angle of the excitation signal, the number of elements, and the distance between elements in the beam steering linear phased antenna array (BSLPAA) using MATLAB.

Directly Connected Linear Antenna Array With Band-Notch Characteristics for UWB Applications

Directly Connected Linear Antenna Array With Band-Notch Characteristics for UWB Applications

CRB-based comparative study of array signal processing direction finding methods supported with SDR platform implementation

Radio Direction-Finding (DF) is an extremely important process in numerous commercial and military applications. Array signal processing-based DF methods have been developed to improve estimation performance in recent applications that require higher resolution and accuracy. Practically, angle of arrival (AOA) estimation is challenging due to various intrinsic and extrinsic parameters that affect the results. Therefore, clarifying these parameters and researching their impact on various DF methods are considered important research topics. The Cramer-Rao Bound (CRB) for estimating AOA is calculated based on a model of a linear antenna array system. This bound identify the factors that significantly impact the estimation performance. The current study conducts a comparative analysis of the most widely used array-signal-processing-based direction-finding (DF) methods under different conditions of the CRB parameters. According to the simulation results, Multiple Signal Classification (MUSIC) AOA estimator provides more accurate and stable results. Accordingly, it is chosen for implementation using a prototype testbed based on Software Defined Radio (SDR) technology using National Instruments Universal Software Radio Peripheral (NI-USRP) platform version 2930. Experimental outcomes were tested at various AOA values. The appendix includes the complete derivation for the CRB relation applied on the system model.

A Simple Blass Matrix Design Strategy for Multibeam Arbitrary Linear Antenna Arrays

A Simple Blass Matrix Design Strategy for Multibeam Arbitrary Linear Antenna Arrays

SLL Reduction in Linear Antenna Arrays by Genetic Algorithm, Flower Pollination Algorithm, and Grey Wolf Optimization with Iteration and Population Parameters

SLL Reduction in Linear Antenna Arrays by Genetic Algorithm, Flower Pollination Algorithm, and Grey Wolf Optimization with Iteration and Population Parameters

Real-time linear antenna array synthesis of broadside pattern using improved dwarf mongoose optimization algorithm

Real-time linear antenna array synthesis of broadside pattern using improved dwarf mongoose optimization algorithm

An experimental study on local and global optima of linear antenna array synthesis by using the sequential least squares programming

Antenna array syntheses are usually nonlinear optimization problems with many local optima and constraints. A mathematical optimizer is limited to solving the synthesis problems in case that it might get trapped in a very poor local optimum. To address how poor the local optima with the synthesis problems, an experimental study is done on the local and the global optima of array syntheses by using the sequential least squares programming (SLSQP), which is a fast mathematical optimizer to search a local optimum. The experimental study show that the patterns of local optima are very close to the global optimal pattern in the case of equally spaced array, while in the case of unequally spaced array, the local and global optimal patterns are likely much different. The SLSQP algorithm is consequently recommended to quickly solve the synthesis problem in the case of equally spaced array. For the case of unequally spaced array, a DE-SLSQP hybrid algorithm is proposed to balance the global search and the quick convergence.

1-D and 2-D Beam Steering Arrays Antennas Fed by a Compact Beamforming Network for Millimeter-Wave Communication

In this article, a new Beamforming Network (BFN) realized in Broadside Coupled Stripline (BCS) is proposed to feed 1 × 4 and 2 × 2 arrays antenna at 28 GHZ-Band. The new BFN is composed only of couplers and phase shifters. It doesn't require any crossover compared to the conventional Butler Matrix (BM) which requires two crossovers. The tight coupling and low loss characteristics of the BCS allow a design of a compact and wideband BFN. The new BFN produces the phase differences of (±90°) and (±45°, ±135°) respectively in x- and y-directions. Its integration with a 1 × 4 linear array antenna reduces the array area by 70% with an improvement of the gain performance compared with the conventional array. The integration with a 2 × 2 array allows the realization of a full 2-D beam scanning. The proposed concept has been verified experimentally by measuring the fabricated prototypes of the BFN, the 1-D and 2-D patch arrays antennas. The measured 11.5 dBi and 11.3 dBi maximum gains are realized in θ0 =14° and (θ0, ϕ0)=(45°,345°) directions respectively for the 1-D and 2-D patch arrays. The physical area of the fabricated BFN is only (0.37λ0 × 0.3λ0 × 0.08λ0), while the 1-D array and 2-D array antennas areas without feeding transmission lines are respectively (0.5λ0 × 2.15λ0 × 0.08λ0) and (0.9λ0 × 0.8λ0 × 0.08λ0).

Optimal Pattern Synthesis of Linear Array Antennas Using the Nonlinear Chaotic Grey Wolf Algorithm

The grey wolf optimization (GWO) algorithm is a new nature-inspired meta-heuristic algorithm inspired by the social hierarchy and hunting behavior of grey wolves. In this paper, the GWO algorithm is improved to overcome previous shortcomings of being easily trapped in local optima and having a low convergence rate. The proposed enhancement of the GWO algorithm utilizes logistic-tent double mapping to generate initialized populations, which enhances its global search capability and convergence rate. This improvement is called the nonlinear chaotic grey wolf optimization (NCGWO) algorithm. The performance of the NCGWO algorithm was evaluated with four representative benchmark functions. Then, the NCGWO algorithm was applied to perform an optimal pattern synthesis of linear array antennas (LAAs) using two distinct approaches: optimizing the amplitudes of the antenna currents while preserving uniform spacing and optimizing the positions of the antennas while assuming uniform excitation. To validate the effectiveness of the proposed approach, the results obtained by the NCGWO algorithm were compared with those obtained by other intelligent algorithms. Additionally, the NCGWO algorithm was applied to a more complex planar antenna array to further validate its performance. Our results demonstrate that the NCGWO algorithm exhibits superior performance regarding electromagnetic optimization problems compared to widely recognized algorithms.

Формирование максимума напряженности электрического поля в заданной точке пространства сфокусированной линейной антенной решеткой

The possibility of forming a maximum of the electric field strength at a given point in space with the help of a focused one-dimensional linear antenna array is considered. It is shown that the location of the maximum electric field strength does not coincide with the point of in-phase addition of electromagnetic waves emitted by the elements of the antenna array - the focusing point. The dependence of the shift of the maximum electric field strength on the focus point for various focal lengths and sizes of antenna arrays is presented. It has been found that the value of the shift in the focusing coordinates is determined only by the size of the antenna array and does not depend on the number of its elements. The relationship between a decrease in the intensity of an electromagnetic wave and a shift in the maximum amplitude of the electric field strength is described. The paper presents the dependences of the amplitude of the electric field strength for antenna arrays of various linear sizes and the calculation results confirmed the theoretical concepts. A phase portrait for antenna arrays of various sizes is presented showing the in-phase arrival of waves at a given point in space. According to the family of dependencies presented in the paper, it can be concluded that the greater the ratio of the linear dimensions of the antenna array to the focal length, the smaller the shift in the maximum amplitude of the electric field strength.re frequency plane as a result of an iterative process, which makes it possible to determine the values of the required function.