Performance Of Antenna Array Research Articles

16-channel sleeve antenna array based on passive decoupling method at 14 T

At ultra-high fields, especially at 14 T, head coil arrays face significant challenges with coupling between elements. Although passive decoupling methods can reduce this coupling, the decoupling elements can cause destructive interference to the RF field of the head array, thus reducing the B1+ efficiency. The B1+ loss due to this effect can be even higher than that due to inter-element coupling. In this study, we develop a novel passive decoupling method to improve the performance of head coil arrays at 14 T. Specifically, passive dipole antennas were utilized to decouple the 16-channel sleeve antenna array, with their positioning optimized to minimize destructive interference with the array’s RF field by increasing their distance from the active antennas. We used electromagnetic simulations to optimize the position of the passive dipoles to obtain the best performance of the array. In addition, we introduced a 16-channel dipole antenna array to compare the array performance when evaluating the sleeve antenna array performance using a human body model. We also constructed the optimized sleeve antenna array and measured its S-parameters to verify the effectiveness of the decoupling strategy. Our results show that the improved passive decoupling method can well reduce the destructive interference of the decoupling elements to the RF field. The sleeve antenna array developed under this method exhibits higher B1+ efficiency and better transmission performance.

Enhancing the performance of graphene and LCP 1x2 rectangular microstrip antenna arrays for terahertz applications using photonic band gap structures

The terahertz (THz) frequency band (0.1–10 THz) has drawn a lot of attention due to the growing demand for greater resolutions, lower latency, faster data rates, and wider bandwidth in 6 G technologies. This range provides data speeds exceeding tens of gigabits per second, large bandwidth, great spectral resolution, and non-ionizing characteristics. THz signals have potential; however they are affected by attenuation, route losses, and atmospheric conditions, necessitating the use of specialised antenna designs. This work presents a 300 GHz rectangular microstrip patch antenna with Graphene as the patch material and Liquid Crystal Polymer (LCP) as the substrate. Photonic band gap (PBG) substrates are used to incorporate cuboid and cylindrical air gaps in square and triangular lattices, hence improving performance. The highest performance is found with cylindrical air gaps in a triangular lattice PBG substrate, which has a bandwidth of 29.56 GHz, a return loss of –48.12 dB, a gain of 10.4 dBi, a directivity of 10.8 dBi, and a radiation efficiency of 91 %. These results establish the proposed antennas as highly effective for broadband and high-speed THz applications, particularly in 6 G systems like advanced sensing applications, ultra-fast device-to-device (D2D) communications, potential beam steering applications, and non-invasive imaging solutions.

Twelve-Element MIMO Wideband Antenna Array Operating at 3.3 GHz for 5G Smartphone Applications

This work presents a 12-element multiple-input–multiple-output (MIMO) wideband antenna array for mobile smartphones. The antenna element is mainly composed of two parts, greatly improving the antenna array bandwidth: one is a meandering, looped radiating element and the other is a U-shaped slot. For the antenna element design, the meandering, looped radiating element measures 12.95 × 6 mm2, while the U-shaped slot has a size of 15 × 3 mm2. Meanwhile, the reflection coefficient indicates that the designed antenna array operates at 3.3 GHz with a bandwidth of 500 MHz; the transmission coefficient shows that the isolation between the antenna elements is better than 12 dB. In addition, more antenna array performances are presented, including nearly omnidirectional radiation characteristics, antenna efficiency ranging from approximately 17 to 60%, envelope correlation coefficients (ECCs) below 0.065, and diversity gain (DG) values of the MIMO antenna system close to 10 dB. The measurement results are highly consistent with the simulation results of the designed wideband antenna array, indicating its great potential for future practical engineering applications.

Simulation and Design of Three 5G Antennas

In the context of 5G networks, this paper investigates microstrip array antennas and mobile terminal MIMO array antennas. It introduces two innovative designs and, based on these, develops and fabricates a mobile terminal antenna. The first of these designs, a 4 × 4 microstrip array antenna operating in the LTE band 42 (3.4–3.6 GHz), is researched and fabricated and an innovative approach, combining embedded and coaxial feeding methods, is proposed and employed. Measurement results indicate a bandwidth of 373 MHz (3.321–3.694 GHz), achieving a relative bandwidth of 10.7%. The antenna exhibits a high gain of 12.7 dBi, with an undistorted radiation pattern, demonstrating excellent directional characteristics. The second of these designs, a “loop-slot” MIMO antenna designed for 5G mobile devices with metal frames, is investigated. By opening slots in the metal frame and integrating them into the antenna’s feeding structure, the decoupling principle is analyzed from the perspective of characteristic mode theory. This design shares resonant modes between the loop and slot antennas, allowing for the overlapping placement of the two antenna units. Experimental results confirm an isolation level exceeding 21 dB, with significantly reduced dimensions. Finally, an eight-unit MIMO antenna is designed and fabricated for 5G mobile devices with metal frames. Continuous optimization of the “loop-slot” module layout and unit spacing leads to a compact and miniaturized antenna structure. Measurement results show an isolation level exceeding 17 dB, radiation efficiency ranging from 65.8% to 73.7%, and an envelope correlation coefficient (ECC) below 0.03. Finally, an analysis of specific absorption rate (SAR) demonstrates excellent MIMO performance in terms of human body radiation exposure.

Synthesis of sparse rectangular planar arrays with weight function and improved grey wolf optimization algorithm

AbstractThe present article proposes a novel hybrid approach for addressing the synthesis problem of rectangular planar arrays under multiple constraints, through joint optimization of the weight function and the improved grey wolf optimization (IGWO) algorithm. Firstly, the grey wolf optimization (GWO) algorithm is improved by using tent chaotic mapping, nonlinear convergence factor, dominant wolf dynamic belief strategy, and opposition‐based learning strategy to increase the population diversity and the ability to jump out of the local optimum. Secondly, the array elements are weighted using the weight function to generate the position distribution matrix, which reduces the thinned matrix optimization time and improves the optimization efficiency. Finally, the position distribution matrix is used to generate the thinned array, and the IGWO algorithm is applied to perform the sparse optimization with multiple constraints. The effectiveness of the method is verified through numerical simulation and full‐wave simulation experiments, demonstrating its capability to enhance array antenna performance and reduce peak sidelobe level (PSLL). These experimental results hold significant engineering implications and provide valuable references for addressing the array distribution problem under multiple constraints.

Coupling Modeling for Ripple of Array Power Supply and Electromagnetic Performance of Active Phased Array Antennas

Coupling Modeling for Ripple of Array Power Supply and Electromagnetic Performance of Active Phased Array Antennas

Far-field pattern accuracy improvement in planar near-field measurement using infinitesimal dipole modeling

This paper discusses the challenges in accurately measuring the far-field performance of array antennas, which have become more complex and larger due to recent trends in increasing the number of elements and the antenna size. The far-field measurement method, which is a general method for measuring a radiation pattern in a far-field, is difficult to be utilized at a high frequency due to limitations in physical chamber size and difficulty in diagnosing an antenna. In order to improve these problems, a near-field measurement method is used as an alternative. Even though using a near-field measurement, the accuracy of the derived far-field pattern is reduced at low elevation angles due to zero-padding of data outside the measurement area. The integration of the near-field measurement with the source reconstruction is a promising approach to enhance the measurement limits of the far-field pattern analysis. This paper aims to extend the previous work to accurately predict the far-field radiation pattern, especially in the low elevation angles. The verification of the proposed method is performed for a standard gain horn and 4 by 4 patch array antennas, with and without beam steering.

Circularly Polarized Series Array and MIMO Application for Sub-Millimeter Wave/Terahertz Band

This article presents a compact, planar, and circularly polarized array antenna operating in the W-band (84.5–110 GHz), with all its prototypes fabricated using a low-cost, traditional, microwave printed circuit board composed of Rogers RT/duroid 5880 (ε<sub>r</sub> = 2.2, tanδ = 0.009). The final design that was fabricated and measured was a 4 × 4 array antenna having an overall size of 9 mm × 20 mm × 0.254 mm that used series feeding to reduce its sidelobes. Measurements of the 4 × 4 patch antenna array showed approximately 6.9% 3-dB axial ratio bandwidth along with 15.2 dBi maximum right-hand circularly polarized (RHCP) antenna gain at 100 GHz. The array antenna yielded RHCP radiation characterized by a low profile, low cross-polarization levels (<−25 dB), low sidelobe levels (≤−10 dB), and high radiation efficiency (>91%). Additionally, a two-port MIMO antenna system was investigated by considering side-by-side and front-tofront configurations, both of which achieved good isolation and considerable envelope correlation coefficient and diversity gain values. Therefore, the proposed series array and MIMO antennas can be reasonable candidates for 6G applications of the sub-THz band (100– 110 GHz) in ultra-high-speed wireless and satellite communication systems.

Improving Scanning Performance of Patch Phased Array Antenna by Using a Modified SIW Cavity and Sequential Rotation Technique

Improving Scanning Performance of Patch Phased Array Antenna by Using a Modified SIW Cavity and Sequential Rotation Technique

Delay analysis of ring resonator-based beam-forming network in z-domain

During the next generation of wireless cellular networks, the millimeter-wave (mm-wave) spectrum will bring new opportunities for exceptionally high data transfer speeds and extensive network connectivity. Millimeter waves, on the other hand, are subject to a significant loss of propagation, which is the most significant impediment. A beneficial solution to this difficulty, which can be overcome, is to use a beam-forming system that consists of many antennas. The purpose of this study is to provide a concept for an integrated photonic beam-forming system that utilises multiple ring resonators for a 1 × 4 phase array antenna operating in the Ka-Band frequency range. The waveguide technology is the foundation for a signal that operates at 28 GHz. It is through the use of the optical ring resonator that the actual time delay line may accomplish its goal. The suggested method can be imDuring the next generation of wireless cellular networks, the millimeter-wave (mm-wave) spectrum will bring new opportunities for exceptionally high data transfer speeds and extensive network connectivity. Millimeter waves, on the other hand, are subject to a significant loss of propagation, which is the most significant impediment. A beneficial solution to this difficulty, which can be overcome, is to use a beam-forming system that consists of many antennas. The purpose of this study is to provide a concept for an integrated photonic beam-forming system that utilises multiple ring resonators for a 1 × 4 phase array antenna operating in the Ka-Band frequency range. The waveguide technology is the foundation for a signal that operates at 28 GHz. It is through the use of the optical ring resonator that the actual time delay line may accomplish its goal. The suggested method can be implemented as a variable true time delay (TTD) line to change the radiation angle of phase array antennas (PAA). The main lobe radiated by the PAA can be directed squint-free between the angles from −28° to +28°. The mathematical analysis and design of the beam producing the structure are presented. Following that, delays of 650 ps, 350 ps, and 250 ps could be produced with coupling coefficients of κ = 0.5 , κ = 0.7, and κ = 0.9 , respectively, and the associated phase shifts were 0.469π, 0.146π, and 0.387π.plemented as a variable true time delay (TTD) line to change the radiation angle of phase array antennas (PAA). The main lobe radiated by the PAA can be directed squint-free between the angles from −28° to +28°. The mathematical analysis and design of the beam producing the structure are presented. Following that, delays of 650 ps, 350 ps, and 250 ps could be produced with coupling coefficients of κ = 0.5 , κ = 0.7, and κ = 0.9 , respectively, and the associated phase shifts were 0.469π, 0.146π, and 0.387π.

An Improved OMP Algorithm for Enhancing the Anti-Interference Performance of Array Antennas.

The demand for precise positioning in noisy environments has propelled the development of research on array antenna radar systems. Although the orthogonal matching pursuit (OMP) algorithm demonstrates superior performance in signal reconstruction, its application efficacy in noisy settings faces challenges. Consequently, this paper introduces an innovative OMP algorithm, DTM_OMP_ICA (a dual-threshold mask OMP algorithm based on independent component analysis), which optimizes the OMP signal reconstruction framework by utilizing two different observation bases in conjunction with independent component analysis (ICA). By implementing a mean mask strategy, it effectively denoises signals received by array antennas in noisy environments. Simulation results reveal that compared to traditional OMP algorithms, the DTM_OMP_ICA algorithm shows significant advantages in noise suppression capability and algorithm stability. Under optimal conditions, this algorithm achieves a noise suppression rate of up to 96.8%, with its stability also reaching as high as 99%. Furthermore, DTM_OMP_ICA surpasses traditional denoising algorithms in practical denoising applications, proving its effectiveness in reconstructing array antenna signals in noisy settings. This presents an efficient method for accurately reconstructing array antenna signals against a noisy backdrop.

Design and Simulation of a High Performance 5G mm-Wave MIMO Antenna Array for Mobile Applications

This paper presents the design and simulation of an efficient multiple input multiple output (MIMO) antenna array for 5G millimeter-wave (mm-wave) mobile applications. With a dielectric constant of 2.2 and a loss tangent of 0.0009, the substrate employed is a Rogers RT5880 that is 0.254 mm thick. The 37 GHz frequency spectrum, reserved for millimeter-wave mobile applications for 5G, is covered by the proposed MIMO antenna arrays. The single antenna element has a gain of 6.44 dBi, which is increased to 7.89 dBi with a two-element array configuration and 10.88 dBi with a four-element array configuration. The proposed MIMO antenna array performance metrics—including reflection coefficient, VSWR, radiation efficiency, and gain—are seen and discovered to be below the accepted threshold. In the desired operating frequency band, it is noticed that more than 85% of the proposed MIMO antenna array's radiation efficiency is achieved. According to simulation findings, the proposed design may be potentially feasible for mobile applications using millimeter waves in the 5G network.

Reliability Evaluation Method for Array Antenna Considering Performance Changes.

The existing array antenna reliability evaluation method based on the n/k system is analyzed. As the failed T/R module's influence on the array antenna's performance is not considered, the reliability of the array antenna is overestimated. To improve the accuracy of the array antenna reliability evaluation, the performance changes caused by T/R failures in different locations are considered. The reliability evaluation method considering the performance changes is established. The performance and probability of the array antenna's state are calculated, and accurate reliability is obtained by calculating all the available state's probabilities. The complexity of the reliability evaluation method is analyzed, and the reliability evaluation method for large-scale array antennae is established. The large-scale array antenna is divided into several subarrays. The performance and reliability of each subarray are analyzed, and the array antenna's reliability is calculated through subarrays. The array antenna's performance changes are considered with the proposed method, the overestimation problem of the existing reliability evaluation method is solved, and the accuracy of the array antenna reliability evaluation is improved.

A Low-profile Dual-band Dual-polarization Co-aperture Array Antenna with High Isolation

This paper proposes a low-profile high-isolation dual-polarization array antenna operating in the L/S band. The radiating unit of the array antenna adopts U-shaped bending dipoles to realize the staggered arrangement of high- and low-band units, and is connected to the feeding network by a coaxial cable. To achieve the non-influence of high-band and low-band feed networks, multi-layer printing technology is used and grooves are etched on the metal plate. In order to reduce the coupling of the high- and low-band dipoles at low frequency, a bandpass filter is added to the high-band feed network, which greatly improves the isolation at low-frequency. The measured results show that the impedance bandwidth of the array is 4.5% (0.971-1.015 GHz) and 7.5% (1.89-2.04 GHz), with gains of 15 and 19 dBi at 1 GHz and 2 GHz, respectively. And the isolation between the dual-polarized ports more than 50 dB and 35 dB was achieved at 1 GHz and 2 GHz, respectively. The proposed array will have practical value in L/S band full-duplex wireless communication systems.

Optimizing Performance of Antenna Arrays with Clustered Fractal Shapes for Multiband Applications

Fractal antennas are mainly used in multiband applications. However, these types of arrays suffer from numerous disadvantages, such as high sidelobe levels, low directivity, poor taper efficiency, and high design computational complexity. In this paper, the conventional fractal procedures are redesigned and efficient clustered subarrays are deployed, such that their multiband properties are maintained while simultaneously achieving significant improvements in radiation characteristics. A genetic optimization algorithm is used to find the optimal clustered fractal shapes and their associated amplitude distributions, such that the sidelobe levels are minimized at the narrower beam width, i.e. maximum feasible directivity. Since the optimization process is carried out at the clustered level, it can be represented by merely a few variables, which solves the problem of time intensity. Simulation results confirm the superiority of the proposed clustered fractal array, where the sidelobe level has been reduced to more than -10 dB over a wide range of frequencies. Directivity and taper efficiency have been improved by more than 6 dB and 50%, respectively, in comparison to the parameters of conventional, original fractal arrays. Moreover, the proposed fractal array pattern offers an additional advantage, as it is capable of wide sidelobe nulling at some undesired directions.

Performance analysis of the dual-band trapezoidal antenna array for ultra-wideband application

Designing a wireless transmission system with high data rates, high fidelity, and small size is a tough undertaking that has become more popular in the digital age. One of the most important components of wireless communication systems, such as wireless LANs, mobile WIMAX, and Bluetooth devices, is the design of an efficient antenna system. The new circular slot Trapezoidal patch antenna array, which operates in the ultra wide band frequency range of 3.1 GHz to 10.6 GHz, is introduced in this study. The FR4 substrate on which the antenna system is built has a dielectric constant of 4.4. The CST microwave studio suite is used to develop and analyze the performance of the compact structure patch antenna array. Antenna performance is examined in the frequency range of 2 GHz to 5 GHz. Antenna array resonance frequency is 3.1 GHz. By inserting a quarter wave line between the SMA connection and the micro stripline, 50 ohm impedance matching may be achieved. In comparison to previous studies, the intended antenna array has a minimum VSWR of 1.18, a maximum radiation efficiency of ?4.842 dB, and a directivity of 8.645 dBi. Using network analyzer, the test and simulation data were analyzed. The intended use of the antenna array system is for biomedical imaging and body area networks. Abbreviations: UWB: ultra wideband; EMI: electromagnetic interference; MIMO: multiple input multiple output; WLAN: wireless local area network; VSWR: voltage standing wave ratio; AVA: antipodal vivaldi antenna; DGS: defected ground structure; RF: radio frequency.

Enhancing long-range radar (LRR) automotive applications: Utilizing metasurface structures to improve the performance of K-band Longitudinal Slot Array Antennas

In this paper, we introduce a groundbreaking modification to a K-band substrate integrated waveguide (SIW) Longitudinal Slot Array Antenna for Vehicle-to-Everything (V2X) applications, particularly long-range radar (LRR) in the automotive industry. Our approach harnesses an elliptic metasurface capable of distinguishing between TE and TM modes in relation to radiation direction. By utilizing metasurfaces, we effectively address the issue of mutual coupling between antenna elements, which often results in subpar antenna performance. This modification focuses on improving various antenna characteristics, including frequency bandwidth (expanded by approximately four times), sidelobe level (reduced by 4 dB), aperture efficiency (increased to about 44%), and cross-polarization (reduced by an average of 10 dB). In essence, the results demonstrate that the increased number of longitudinal elements can be effectively enhanced by utilizing the metasurface structure, while maintaining an acceptable level of efficiency. As an illustrative case, we design a 1 × 32-element Longitudinal Slot Array Antenna using the Elliott method operating at 24.3 GHz, with the antenna size measuring 12.5 × 154 mm2. Experimental measurements validate our design, showcasing a 10 dB return loss bandwidth of 24.05–24.45 GHz, a maximum gain of 14.45 dBi, a sidelobe level of 24.5 dB, cross-polarization exceeding 30 dB, and an impressive aperture efficiency of 65%.

An Analytical Investigation on the Performance of 1D and 2D Antenna Arrays for mm-Wave Modern Communication Systems

Millimeter wave (mm-Wave) wireless technology has invaded every aspect of modern life because of its ability to transmit data quickly and securely. This paper presented a square patch antenna at a resonance frequency of 26.2GHz for millimeter wave wireless communication. The proposed antenna consists of single square radiating element. The suggested antenna was designed using CST Microwave Studio’s version 2020 on a Rogers RO 3003 lossy substrate with a relative permittivity of 3 . The result of this paper shows a minimum S11 of 19.34 dB, a gain of 6.97dBi, with bandwidth of 2GHz at the resonant frequency of 26.2GHz. The gain was enhanced to 16dBi and 25.8dBi with a high radiation efficiency by converting the single element patch antenna to a uniform linear array of 8 elements and uniform planar array of 8 × 8 elements respectively. The simulation results show that despite the simple design of the patch (without holes and cracks), which facilitates manufacturing in a small size; However, it achieves higher gain than the more complex designs found in the previous literature to suit mm wave communication requirements. Also, we used CST Microwave Studio for simulation which provides two methods for implementing arrays: the array factor method, which builds virtual arrays (the direct method), or building arrays by repeating the elements depending on the required size of the array, A comparison has been conducted between the numerical analysis of both methods, and the results show that even though the numerical analysis of the second method gives more accurate results that can be close to a manufactured antenna array, it needs high processing ability and time. Creating arrays with array factor may save time and processing ability but the results may not be accurate. Therefore, a relation was driven to show the error that can be added to give precise results.

Effect of polarized signals on the performance of adaptive antenna arrays

Effect of polarized signals on the performance of adaptive antenna arrays

Novel broadband circularly polarized pentagonal printed antenna design for wireless power transmission applications

<p>This paper provides a new conception for a microstrip patch antenna array that operates in a circularly polarized manner for wireless power transmission (WPT) at 2.45 GHz. The proposed conception combines four pentagonal patches and the defected ground structure (DGS) method. The antenna array with a dielectric constant of 4.4 and a tangential loss of 0.025 is printed on a FR4 where its thickness is about 1.58 mm. The developed design aims to optimize the antenna array performance. Th e main contribution, to the telecommunications and WPT fields, is to achieve a maximum energy transfer with low losses, while also ensuring adequate adaptation to the excitation port. To prove the effectiveness of this design, simulation results were obtai ned using computer simulation technology microwave studio (CST MWS) software and validated by another solver high - frequency structure simulator (HFSS). Simulation results are presented and compared with those obtained using existing conceptions in the lite rature. The proposed design has proven to be very effective in achieving the intended objectives, which makes this design very good for radiofrequency (RF) energy collection and its various applications to power a variety of devices without harming our pla net.</p>