Circular Antenna Array Research Articles

On the possibility of long‐distance transmission of OAM beam in rectangular tunnels

AbstractThis letter explores the possibility of long‐distance transmission of an orbital angular momentum (OAM) beam through rectangular tunnels. Theoretical analysis reveals that the OAM beam propagating in the tunnel with square cross section fulfills the conditions for axial propagation and exhibits azimuth symmetry. In comparison with free‐space OAM generation, we draw the conclusion that long‐distance transmission of OAM beams is achievable in the tunnels with square cross section. The validity of our conclusion is further substantiated through numerical experiments. Simulation results demonstrate that the first‐order OAM beam radiated by a uniform circular antenna array exhibits favorable helical phase distribution and the circular symmetry of the amplitude distribution in the tunnel beyond the Rayleigh distance. However, these characteristics degrade with increasing mode order and propagation distance, because the increase of high‐order OAM beam divergence angle and propagation distance will exacerbate the impact of multipath effects in the tunnel environment.

Radiation Pattern Analysis and Phase Shifter for Base Station Mobile Communication Circular Array Antenna at 900MHz Frequency by Using 4NEC2X Software

Background: This paper presents the utilization of phase shifters to manipulate and control the radiation patterns in Uniform Circular Array (UCA) antennas. UCAs, known for their 360-degree coverage and symmetrical radiation patterns, are enhanced by incorporating phase shifters, enabling dynamic beam steering and pattern shaping. Materials and Methods: A uniform circular antenna array operating at 900 GHz frequency has been intended for use in base stations using 4NEC2X simulation software. Results: A single-element dipole antenna having a 2.14 dBi gain is used as a base for constructing a uniform 0.5 λ spacing circular array. The number of elements gradually increased from 2 to 12, raising the gain to 12.3 dBi. HPBW decreased both in vertical and horizontal plans from 80o to 60o and 360o to 20o respectively this implies that the circular array antenna's directivity is enhanced. The eight-element array beam scanning was performed from 0o to 360o without any distortion in radiation pattern, gain, and directivity, contradictory with the linear array. Conclusions: The studied case and simulation output illustrate the impact of the element numbers and phase shifter configurations on properties of the radiation pattern of the uniform circular array can be obtained when increasing the number of elements, the gain increases too and scanning the main beam without any change and distortion

Dual‐port circular patch antenna array: Enhancing gain and minimizing cross‐polarization for mm‐wave 5G networks

Dual‐port circular patch antenna array: Enhancing gain and minimizing cross‐polarization for mm‐wave 5G networks

Synthesis of concentric circular antenna array for reducing the sidelobe level by employing sine cosine optimization algorithm

AbstractThe sine cosine algorithm (SCA), a meta‐heuristic optimization method, is used in this study to provide a precise linear and elliptical antenna array design for synthesizing the ideal far‐field radiation pattern in the fifth‐generation (5G) communication spectrum. The wireless communication system will undergo dramatic changes thanks to the forthcoming 5G technology, which offers exceptionally high data rates, increased capacity, reduced latency, and outstanding service quality. The most important component of 5G communications is an accurate antenna array design for an optimum far‐field radiation pattern synthesis with a suppressed sidelobe level (SLL) value and half power beam width (HPBW). While long‐distance communication necessitates a low HPBW, the entire side lobe area needs a suppressed SLL to prevent interference. The SCA is used in this case to the optimal feeding currents applied to each array member in the design examples of the concentric circular antenna arrays (CCAA) discussed in this article. It shows the litheness and attainment of the propound algorithm named SCA, chosen CCAAs with three rings and varying amounts of components or antenna array sets those are stated as follows: Set I (4, 6, 8 elements), Set II (8, 10, 12 elements), Set III (6, 12, 18 elements), Set IV (8, 14, 20 elements) with and without the center element are amalgamate. Apply the PSO, Jaya, and SCA optimization algorithms for all four Sets of antenna arrays and compare the attained results; the SLL values achieved by the SCA technique are contrasted with those of other current optimization techniques. The outcomes of all examinations reveal that the SCA algorithm achieved a superior SLL reduction over other optimization techniques.

Complementary split resonant ring inspired wide-angle frequency-scanning patch array leaky-wave antenna with open-stopband suppression

In this paper, a wide-angle scanning and dual-linearly polarized leaky-wave antenna (LWA) is proposed based on symmetrical complementary split resonant ring (CSRR) feeding lines. The CSRR excites high-dispersed spoof surface plasmon polaritons (SSPPs) and is inspired to enlarge the scanning angle of the circular patch array antenna. The coupling between CSRR and circular patch determines the unit cell dispersion characteristics of LWA, and the coupling between CSRR and circular patch is controlled by designing their respective periods, p/b, to suppress the open-stopband and reduce the grating lobe, The value of p/b controls the frequency range of the open-stopband. Two parallel CSRR feeding lines are located on the bottom layer of the antenna and feed the array antenna of 11 circular patches above the feeding layer with both differential and common modes excitations. The two modes switch with 1-bit phase shifters on the two parallel feeding lines fed with a Wilkinson power splitter and electronically switch dual-linearly polarized radiations. The proposed scenario of the LWA prototype is validated through simulations and experiments. According to the measurements, horizontally polarized radiation achieves large beam scanning angle from −59.5° to +40° in the frequency range from 8 to 11 GHz with common mode excitation. And vertically polarized radiation scanning the main beam from −47° to +41° in the frequency range from 7.8 to 10.8 GHz with differential-mode excitation. The measured peak gains of the two polarizations are 14.4 dBi and 14.2 dBi, respectively, and the cross-polarization ratios are above 21 dB.

Optical integrated reconfigurable mode generator-multiplexer for radio-frequency orbital angular momentum.

Radio-frequency orbital angular momentum (RF-OAM) mode multiplexing has received increasing attention in next-generation (6G) wireless communication as a new spatial multiplexing dimension to further extend data capacity. In particular, the circular antenna array (CAA) based RF-OAM generation using photonic methods is a promising approach due to its flexible reconfigurability, low propagation loss, high operating bandwidth, and high pattern quality. However, most current reports focus either on the bulk optics-based implementations or on band-limited delay line-based approaches. In this paper, we present a novel phased array-based integrated photonic RF-OAM generator-multiplexer for a four-antenna CAA system supporting three RF-OAM modes at 16 GHz for both fast mode switching and mode multiplexing. It consists of a specially designed interleaved optical filter and a four-element phased array based on cascaded phase shifters. By changing the pair of wavelengths used, the output RF-OAM modes can be quickly switched between fundamental mode and ±1 modes. A bandwidth of 1 GHz was experimentally demonstrated. Mode multiplexing can be achieved when all three wavelength pairs are loaded.

Synthesis of Circular Antenna Arrays for Achieving Lower Side Lobe Level and Higher Directivity Using Hybrid Optimization Algorithm

Circular antenna arrays (CAAs) find extensive utility in a range of cutting-edge communication applications such as 5G networks, the Internet of Things (IoT), and advanced beamforming technologies. In the realm of antenna design, the side lobes levels (SLL) in the radiation pattern hold significant importance within communication systems. This is primarily due to its role in mitigating signal interference across the entire radiation pattern’s side lobes. In order to suppress the subsidiary lobe, achieve the required primary lobe orientation, and improve directivity, an optimization problem is used in this work. This paper introduces a method aimed at enhancing the radiation pattern of CAA by minimizing its SLL using a Hybrid Sooty Tern Naked Mole-Rat Algorithm (STNMRA). The simulation results show that the hybrid optimization method significantly reduces side lobes while maintaining reasonable directivity compared to the uniform array and other competitive metaheuristics.

A mutation hill climber for thinning of concentric circular antenna arrays

ABSTRACT Thinned concentric circular antenna arrays (CCAAs) are crucial in modern wireless communication systems. CCAAs are widely used for efficient communication, directivity, and beamforming capabilities. Nevertheless, CCAAs encounter a challenge of radiation patterns characterised by high sidelobe levels (SLL). Designing thinned CCAAs to surmount this limitation for optimal performance can be complex and challenging. This paper employs a mutation hill climber (MHC) algorithm to optimise the CCAA structure. The goal is to attain an optimal design that balances the number of switched-on elements and reduces the maximum SLL. The performance and efficacy of the MHC are examined using two different cases of thinned CCAA design: two-ring and ten-ring configurations. Simulation results reveal the superiority of the MHC over the latest binary metaheuristic techniques in achieving the lowest maximum SLL and the number of switched-on elements. For the two-ring thinned CCAA, the MHC effectively switched off 50 antenna elements, reducing the maximum SLL by 24.92 dB. Meanwhile, for the ten-ring thinned CCAA, the MHC reduced the number of switched-on antenna elements from 440 to 184, reducing the maximum SLL by 34.09 dB.

An optimal concentric circular antenna array design using atomic orbital search for communication systems

Abstract In this study, optimum radiation patterns of Concentric Circular Antenna Arrays (CCAAs) are obtained by using the Atomic Orbital Search (AOS) algorithm for communication spectrum. Communication systems stands as a nascent technological innovation poised to revolutionize the landscape of wireless communication systems. It distinguishes itself through its hallmark features, notably an exceptionally high data transmission rate, expanded network capacity, minimal latency, and a commendable quality of service. The most important issue in wireless communication is a precision antenna array design. The success of this design depends on suppressing the maximum sidelobe levels (MSLs) values of the antenna in the far-field radiation region as much as possible. The AOS, which is a rapid and flexible search algorithm, is a novel physics-based algorithm. The amplitudes and inter-element spacing of CCAAs are optimally determined by utilizing AOS to the reduction of the MSLs. In this study, CCAAs with three and four rings are considered. The number of elements of these CCAAs has been determined as 4–6–8, 8–10–12 and 6–12–18–24. The radiation patterns obtained with AOS are compared with the results available in the literature and it is seen that the results of the AOS method are better.

Hybridization of almost difference sets and DFT technique for concentric circular antenna array thinning

This paper introduces a hybrid methodology for minimizing the peak sidelobe level (PSLL) in concentric circular antenna arrays (CCAAs). Traditionally, the almost difference set (ADS) approach has been utilized for determining active element positions, but its effectiveness in PSLL reduction is limited. To address this limitation, the proposed methodology integrates the ADS approach with the discrete Fourier transform (DFT) technique. This integration optimizes excitation amplitudes for activated elements within the ADS-based thinned array, resulting in significant PSLL reduction. Simulation results across various case studies demonstrate that the hybrid ADS-DFT method achieves lower PSLL values than existing thinning techniques while maintaining high computational efficiency. Additionally, electromagnetic (EM) simulations validate the efficiency of the proposed method, considering mutual coupling effects.

Experimental Evaluation of an SDR-Based UAV Localization System.

UAV communications have seen a rapid rise in the last few years. The drone class of UAV has particularly become more widespread around the world, and illicit behavior using drones has become a problem. Therefore, localization, tracking, and even taking control of drones have also gained interest. Knowing the frequency of a target signal, its position can be determined (as the angle of arrival with respect to a fixed receiver point) using radio frequency-based localization techniques. One such technique is represented by the subspace-based algorithms that offer highly accurate results. This paper presents the implementation of the MUSIC algorithm on an SDR-based system using a uniform circular antenna array and its experimental evaluation in relevant outdoor environments for drone localization. The results show the capability of the system to indicate the AoA of the target signal. The results are compared with the actual direction computed from the log files of the drone application and validated with a professional direction-finding solution (i.e., Narda SignalShark equipped with the automatic direction-finding antenna).

Withdrawal Notice: Design and Synthesis of Circular Antenna Array for Low Side Lobe Level and High Directivity Using Artificial Hummingbird Optimization Algorithm

The article has been withdrawn at the request of the authors of the journal Recent Advances in Electrical and Electronic Engineering. Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused. The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.com/editorial-policiesmain. php. BENTHAM SCIENCE DISCLAIMER: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

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.

Optimal pattern synthesis of circular antenna arrays with improved effective aperture and beam area

Abstract Circular antenna array (CAA) is one of the most widely used antenna array designs. This paper addresses the design challenges of the CAA with the non-uniform single ring, which is placed in an X-Y plane with the best sidelobe level (SLL) and improved first null beamwidth (FNBW). It has been solved using differential evolution, craziness-based particle swarm optimization (CRPSO), and novel particle swarm optimization (NPSO) techniques. An optimal combination of feeding current and inter-element spacing provides an array pattern with the best SLL and improved FNBW, as well as some other parameter calculations of the antenna array like maximum directivity, maximum effective aperture, total effective aperture, maximum beam area, total beam area, circumference, and radius of the CAAs using these techniques. There are six designs of CAAs with different antenna elements (i.e., 10-, 12-, 16-, 20-, 36-, and 64-elements) which have been taken into account. Simulations are done in MATLAB. Based on various simulation results, we can analyze the performance of SLL and FNBW with other parameters using NPSO and compare them with different techniques of CAAs, as shown in the numerical analysis and simulation result section.

Distributed Sensitivity and Critical Interference Power Analysis of Multi-Degree-of-Freedom Navigation Interference for Global Navigation Satellite System Array Antennas.

Current research on the interference of GNSS (Global Navigation Satellite System) array antennas focuses on the single interference effect and the improvement of interference hardware capability, while the multi-degree-of-freedom (DOF) interference model and mechanism remain to be fully studied. Aiming at this problem, this paper analyzes the preconditions for the definition of anti-jamming degrees of freedom and the characteristics of super-DOF interference through formula derivation and simulation. First, by analyzing the influence of the number of interfering signals on the angular resolution, the prerequisite of the definition of anti-interference degrees of freedom in the airspace is proposed. Second, the definition of anti-interference degrees of freedom is used to calculate the change rule of the critical power of the interference under different numbers of interfering signals. Finally, the influence of super-DOF interference on the array antenna is analyzed. The results show that the prerequisite for the anti-interference freedom of the array antenna is that the distribution interval of the interfering signal is greater than 15°, taking a four-array element uniform circular array antenna as an example. The critical interference power of the array antenna decreases by about 15 dB when the number of interfering signals exceeds the degrees of freedom of the array antenna's interference immunity, provided that the interference resolution is satisfied. The conclusions of this paper give the critical power change rule of multi-DOF interference and the effect of super-DOF interference, as well as the prerequisites for the setting of interference signals, which can be used, for example, in the deployment of distributed interference sources and the development of anti-jamming algorithms.

Redefining uniform circular array’s limit by using square patch elements for higher order orbital angular momentum mode generation

This article proposes a technique to design the Uniform Circular Array (UCA) antenna for the generation of higher order of orbital angular momentum (OAM) modes using lesser number of antenna elements. Earlier, the highest possible OAM mode number (lmax) generated using conventional N-element UCA is limited by number of antenna elements N ≥ 2|lmax|. In the proposed design, a square patch element is placed between two antenna elements of conventional 4-element UCA to generate higher order OAM modes (0, ±1, ±2, and ±3 OAM modes) with lesser number of antenna elements. The proposed UCA is compact in size and requires less complex power dividing phase networks in comparison to conventional 8-element UCA to generate similar lmax. The proposed UCA with square patch is designed at 5.2 GHz and lmax of a N-element UCA with square patch is now limited by number of antenna elements as N ≥ |lmax|. The simulated and measured phase patterns for various OAM modes are in good agreement and supported by mathematical analysis. A comparison of the new structure with the conventional Uniform Circular Arrays available in the literature is also tabulated.

Massive MIMO With Circular Antenna Array: Design, Implementation, and Validation

Massive MIMO With Circular Antenna Array: Design, Implementation, and Validation

A computational model for generating multihyperuniform distributions for realistic antenna array and metasurface designs

This paper is aimed at studying the concept of multihyperuniformity and applying it to the design of shared-aperture antenna arrays and multi-bit coding metasurfaces. By formulating the theoretical foundation and essential geometric aspects related to this distribution, we create a computational model capable of generating both single hyperuniform and multihyperuniform distributions. Moreover, we put forward specific convergence acceleration techniques that effectively minimize computational time, particularly when dealing with a substantial number of elements. Considering the shape, size, and corresponding geometric constraints of the elements, we generate patterns suitable for practical designs of antenna arrays, as well as metasurfaces. We present an example of a multihyperuniform shared-aperture antenna array as illustration. Specifically, a penta-band circular patch antenna array operating in the C-band with low sidelobes and high realized gain over five different frequency bands is demonstrated. The computational model is also implemented for the design of a multi-bit coding metasurface with scattering reduction attributes.

Efficient and Accurate Pattern Synthesis of Circular Antenna Array Employing Iterative Fast Segmented Cyclic Convolution

Efficient and Accurate Pattern Synthesis of Circular Antenna Array Employing Iterative Fast Segmented Cyclic Convolution

High Purity Orbital Angular Momentum Modes Reconfiguration Using Uniform Circular Array Antenna to Enhance Channel Capacity and Spectral Efficiency

Technology based on OAM (orbital angular momentum) has great potential for enhancing the bandwidth efficiency of telecommunication systems. Although OAM waves are orthogonal, it is possible to multiplex various modes within a single frequency channel. Significantly, the overall spectrum efficiency, as well as channel capacity, can be improved. Multiple users can share the same frequency channel by using orthogonal modes, which eliminates the requirement for extra resources like time and frequency. This research uses MATLAB code to derive a uniform circular array (UCA) antenna factor under the cylindrical coordinate system. This factor is used to illustrate the array antenna's electric field to generate OAM waves or radio waves that carry the OAM mode. OAM modes can be reconfigured for the no. of UCA elements (N) needed to generate a ripple-free radiation pattern based on the UCA antenna factor. Additionally, the significance of UCA radius and observational distance (the field plane-UCA plane gap) on the phase distribution and radiation pattern from OAM mode 1 to 5 is graphically evaluated and optimized. The MATLAB simulations compute the electric field phase distribution pattern (EFPDP) and normalized radiation pattern (NRP) at 76 GHz. The method predicts the peak, side lobes, and comparable radiation patterns of the radiation pattern, offering an effective means of optimizing OAM modes and analysing trade-offs.