Journal articles: 'Uniform Linear Array'

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Venkata Rama Rao, S., A. Mallikarjuna Prasad, and Ch Santhi Rani. "Direction of Arrival Estimation of Uncorrelated Signals Using Root-MUSIC Algorithm for ULAs and UCAs." International Journal of Engineering & Technology 7, no. 4.36 (2018): 398. http://dx.doi.org/10.14419/ijet.v7i4.36.23813.

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In this paper, Root-MUSIC algorithm for direction of arrival (DOA) estimation of uncorrelated signals is explored both for uniform linear and uniform circular arrays. The basic problem in Uniform Linear Arrays (ULAs) is Mutual coupling between the individual elements of the antenna array. This problem is reduced in Uniform Circular Arrays (UCAs) because of its symmetric structure. The DOA estimation of uncorrelated signals that have different power levels is simulated on a MATLAB environment. And the noise consider is white across all the array elements. The factors considered for simulation are number of number of snapshots, array elements, radius of circular array, array length, and signal to noise ratio.

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Chepala, Anil, Vincent Fusco, Umair Naeem, and Adrian McKernan. "Uniform Linear Antenna Array Beamsteering Based on Phase-Locked Loops." Electronics 12, no. 4 (2023): 780. http://dx.doi.org/10.3390/electronics12040780.

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Phased arrays are extensively used in many modern beam-scanning applications such as radar and satellite communications. Electronic beam scanning makes phased arrays an important aspect of modern antenna array systems. This Tutorial aims to promote the basic understanding of the principle and operation of a phased array to general undergraduate students. This paper starts with a discussion on the theory of operation and some basic definitions of antenna parameters followed by derivations of two-element and N-element array patterns and, finally, a five-element array design. The essential hardware based on Phase-Locked Loops (PLLs) as phase controllable RF sources required to build an array and the basic tools required for software and measurement set-up to demonstrate the beam-scanning phased array operation are presented. This enables students to quickly understand and set-up an experiment to verify the phased array operation with commercial off-the-shelf components. In addition, the hardware and software necessary for autonomous control are discussed. By combining basic concepts of phase arrays with a series of simple coding and intuitive laboratory experiments, students can easily understand the Uniform Linear Array (ULA) scanning operation.

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HOU, Shuhua, Xuanzhi ZHAO, Zengli LIU, Yi PENG, and Na WANG. "Ternary redundant sparse linear array design with high robustness." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 41, no. 1 (2023): 125–35. http://dx.doi.org/10.1051/jnwpu/20234110125.

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Sparse linear array is prone to element failure affected by environmental and other factors in practical application, resulting in the decline of degrees of freedom and the attenuation or even failure of direction of arrival (DOA) estimation performance. To address this problem, a ternary redundant sparse array composed of three uniform linear arrays with different spacings at specific distances is designed, and the analytical expression of its degrees of freedom is derived. The configuration rules of the array are concise, and the difference coarrays of the array are hole-free. Mathematically proves that all virtual array elements can be covered with a weight of not less than 3 except the 4 farthest. The array has lower sensors importance and less generalized k-fragility. The array design takes into account the maximum degrees of freedom, redundancy and sparsity. In case of sensors failure, compared with the other sparse linear arrays, the array has more stable difference coarrays and higher uniform degrees of freedom. Compared with multiple-fold redundancy arrays, the array has lower mutual coupling. Simulation results show that the ternary redundant array has superior robustness and higher DOA estimation accuracy under sensors failure.

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NamGoong, Geol, Jong-Tae Lim, and Do-Sik Yoo. "ESPRIT target position estimation with uniform linear array and uniform circular array." Journal of Korea Navigation Institute 16, no. 6 (2012): 952–59. http://dx.doi.org/10.12673/jkoni.2012.16.6.952.

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Tang, Yujia, Zhangjian Li, Yaoyao Cui, Chen Yang, Jiabing Lv, and Yang Jiao. "Micro Non-Uniform Linear Array (MNULA) for Ultrasound Plane Wave Imaging." Sensors 21, no. 2 (2021): 640. http://dx.doi.org/10.3390/s21020640.

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Ultrasound plane wave imaging technology has been applied to more clinical situations than ever before because of its rapid imaging speed and stable imaging quality. Most transducers used in plane wave imaging are linear arrays, but their structures limit the application of plane wave imaging technology in some special clinical situations, especially in the endoscopic environment. In the endoscopic environment, the size of the linear array transducer is strictly miniaturized, and the imaging range is also limited to the near field. Meanwhile, the near field of a micro linear array has serious mutual interferences between elements, which is against the imaging quality of near field. Therefore, we propose a new structure of a micro ultrasound linear array for plane wave imaging. In this paper, a theoretical comparison is given through sound field and imaging simulations. On the basis of primary work and laboratory technology, micro uniform and non-uniform linear arrays were made and experimented with the phantom setting. We selected appropriate evaluation parameters to verify the imaging results. Finally, we concluded that the micro non-uniform linear array eliminated the artifacts better than the micro uniform linear array without the additional use of signal processing methods, especially for target points in the near-field. We believe this study provides a possible solution for plane wave imaging in cramped environments like endoscopy.

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Ahmad, Zeeshan, Zain ul Abidin Jaffri, Shu-Di Bao, and Meng Chen. "Frequency diverse array radar with non-uniform array spacing based on sigmoid function." Journal of Electrical Engineering 73, no. 1 (2022): 36–42. http://dx.doi.org/10.2478/jee-2022-0005.

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Abstract As a widely recognized electronic beam steering concept, frequency diverse array (FDA) radar is an effective and feasible solution to provide beam scanning ability in both angle as well as range dimension as a function of time. However, the conventional FDA radar employing progressive incremental frequency offsets across the array elements generates an S-shaped and range-angle coupled beampattern. As such, the FDA beampattern can be decoupled into range-angle dimensions by employing non-linear frequency offsets or using non-uniform arrays. Frequency offsets design has been extensively researched in recent years, whereas non-uniform arrays were given little attention so far. In this paper, we propose a novel FDA radar with a unified configuration of non-uniform linear array, and non-linear frequency offsets to achieve a high-resolution dot-shaped range-angle dependent beampattern. More specifically, the non-uniform inter-element spacing is calculated using the sigmoid function, and non-linear frequency offsets are generated by logistic map, and triangular window function. Simulation results clearly demonstrate the performance advantages of the proposed FDA radar in terms of beam width and side lobe levels.

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An, Zhi Juan, Yan Dong Zhang, and Liang Xu. "Research on the Phase Center of Uniform Linear Array." Advanced Materials Research 1049-1050 (October 2014): 2037–40. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.2037.

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Accurate estimation of array’s phase center is of great importance in navigation, tracking and other aircraft and aerospace systems. In this paper first the effect of reference point on the phase pattern of a uniform linear array is studied and the phase center of the array is estimated. Then the effect of beamsteering on the location of phase center in phased arrays is theoretically analyzed, finally numerical simulations are carried out and the results are in good agreement with the theoretical analysis.

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Fawad, Iffath, and H. V. Kumaraswamy. "Extended Nested Array Configuration with Increased Degrees of Freedom for DOA Estimation." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (2022): 1830–35. http://dx.doi.org/10.22214/ijraset.2022.42650.

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Abstract: In this paper, a new linear array configuration inspired by the two-level Nested Array concept has been proposed. The proposed geometry comprises of two Uniform Linear Arrays (ULAs) with different spacings and an additional element, this geometry results in a hole-free Difference Co-Array (DCA). In comparison to most of the existing sparse array configurations, the proposed geometry has simple closed-form expressions for the element positions and Degrees of Freedom (DoFs), also providing consecutive DoFs hence, avoiding the need for spatial interpolation. Spatially Smoothed MUltiple SIgnal Classification (SS-MUSIC) algorithm has been deployed for Direction of Arrival (DOA) estimation. Numerical simulations using MATLAB are performed to exhibit the superior performance of the proposed geometry. Keywords: DOA estimation, Co-array Processing, Spatial Smoothing, Degrees of Freedom, Non-Uniform Linear Arrays

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Ibrahim, Dlnya, and Aras Mahmood. "Linear 2.4 GHz Array Optimization Using Genetic Algorithm Technique." Journal of Zankoy Sulaimani - Part A 25, no. 1 (2023): 11. http://dx.doi.org/10.17656/jzs.10907.

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Genetic algorithm (GA) is global numerical optimization approach is based on the genetic recombination and assessment in nature. This kind of optimization can be utilized to optimize the amplitude, phase levels and spacing distribution for the elements of an antenna array to achieve its best performance. In this study the genetic algorithm of the 4NEC2X software has been used to optimize the element spacing ( of both a uniform and non-uniform (Binomial and Chebyshev) current excitation for 10-element, 2.4 GHz linear broadside dipole antenna arrays. As a consequence, for the above-mentioned array antennas the spacing optimization yielded a notable improve in their directivity and Gain (dBi), such that for the uniform current excitation the gain was reached to 14.8dBi and for both Binomial and Chebyshev non-uniform current excitation the gain increased to 12.57 dBi and 15.04 dBi respectively.

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Tewfik, A. H., and W. Hong. "On the application of uniform linear array bearing estimation techniques to uniform circular arrays." IEEE Transactions on Signal Processing 40, no. 4 (1992): 1008–11. http://dx.doi.org/10.1109/78.127980.

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Palacios, Joan, Donno Danilo De, and Joerg Widmer. "Lightweight and Effective Sector Beam Pattern Synthesis with Uniform Linear Antenna Arrays." IEEE Antennas and Wireless Propagation Letters 16 (July 27, 2016): 605–8. https://doi.org/10.1109/LAWP.2016.2594092.

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In this letter, we present a lightweight and effective method for the synthesis of sector beam patterns by using uniform linear arrays. With the objective to approximate a desired array-factor response, we formulate an optimization problem that can be simplified and solved in closed form assuming real instead of complex array weights. As a solution to this problem, we derive a compact expression to compute the optimal array weights as a function of only the desired beamwidth and steering direction. Numerical experiments demonstrate that, compared to classical, state-of-the-art techniques, our solution can better approximate the target radiation mask, yet requires one order of magnitude lower computational complexity.

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Pratik, Tawde*1 Servesh Gupta2 Shrinivas Paivernekar3 &. Pranjali Shelke4. "SIMULATION OF MICROSTRIP ANTENNA PHASED ARRAY USING UNIFORM AND BINOMIAL DISTRIBUTIONS AND SCHELKUNOFF'S POLYNOMIAL BASED ARRAY BEAM SYNTHESIS METHOD USING MATLAB." GLOBAL JOURNAL OF ADVANCED ENGINEERING TECHNOLOGIES AND SCIENCES 5, no. 4 (2018): 10–14. https://doi.org/10.5281/zenodo.1238610.

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Antennas with given radiation pattern may be arranged in a pattern (line, circle, plane etc.) to yield a different radiation pattern. An antenna array is a configuration of multiple antennas (elements) arranged to achieve the given radiation pattern. These arrays are classified as linear array, circular array, planar array etc. based on placement or an arrangement of these multiple elements in a specific geometrical shape. There are multiple design issues of the antenna array are available in the form of different variables such as, shape of the array, element spacing between array elements, excitation amplitude of individual array element, excitation phase of the individual array element, patterns of array elements etc.

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Mei, Fengtong, Daming Wang, Chunxiao Jian, Yinsheng Wang, and Weijia Cui. "A Design Method of Sparse Array with High Degrees of Freedom Based on Fourth-Order Cumulants." Mathematical Problems in Engineering 2021 (July 1, 2021): 1–13. http://dx.doi.org/10.1155/2021/9915963.

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Recently, the design of sparse linear array for direction of arrival (DOA) estimation of non-Gaussian signals has attracted considerable interest due to the fact that the fourth-order difference coarray offered by non-Gaussian significantly increases the aperture of a virtual linear array, which improves the performance of DOA estimation. In this paper, a super four-level nested array (S-FL-NA) configuration based on fourth-order cumulants (FOC) is proposed. The S-FL-NA consists of uniform linear arrays which have different interelement spacing. The proposed array configuration is designed based on interelement spacing, which, for a given number of sensors, is uniquely determined by a closed-form expression. We also derive the closed-form expression for the degrees of freedom (DOFs) of the proposed array. The optimal distribution of the number of sensors in each uniform linear array of the proposed array is given for an arbitrary number of sensors. Compared with the existing sparse arrays, the proposed array can provide a higher number of degrees of freedom and a larger physical array aperture. In addition, to improve the calculation speed of the fourth-order cumulant matrix, we simplify the FOC matrix by removing some redundancy. Numerical simulations are conducted to verify the superiority of the S-FL-NA over other sparse arrays.

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Liu, Chang, Xiao Tang, and Zhi Zhang. "A New Gain-Phase Error Pre-Calibration Method for Uniform Linear Arrays." Sensors 23, no. 5 (2023): 2544. http://dx.doi.org/10.3390/s23052544.

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In this paper, we consider the gain-phase error calibration problem for uniform linear arrays (ULAs). Based on the adaptive antenna nulling technique, a new gain-phase error pre-calibration method is proposed, requiring only one calibration source with known direction of arrival (DOA). In the proposed method, a ULA with M array elements is divided into M−1 sub-arrays, and the gain-phase error of each sub-array can be uniquely extracted one by one. Furthermore, in order to obtain the accurate gain-phase error in each sub-array, we formulate an errors-in-variables (EIV) model and present a weighted total least-squares (WTLS) algorithm by exploiting the structure of the received data on sub-arrays. In addition, the solution to the proposed WTLS algorithm is exactly analyzed in the statistical sense, and the spatial location of the calibration source is also discussed. Simulation results demonstrate the efficiency and feasibility of our proposed method in both large-scale and small-scale ULAs and the superiority to some state-of-the-art gain-phase error calibration approaches.

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Saxena, Prerna, and Ashwin Kothari. "Optimal Pattern Synthesis of Linear Antenna Array Using Grey Wolf Optimization Algorithm." International Journal of Antennas and Propagation 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/1205970.

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The aim of this paper is to introduce the grey wolf optimization (GWO) algorithm to the electromagnetics and antenna community. GWO is a new nature-inspired metaheuristic algorithm inspired by the social hierarchy and hunting behavior of grey wolves. It has potential to exhibit high performance in solving not only unconstrained but also constrained optimization problems. In this work, GWO has been applied to linear antenna arrays for optimal pattern synthesis in the following ways: by optimizing the antenna positions while assuming uniform excitation and by optimizing the antenna current amplitudes while assuming spacing and phase as that of uniform array. GWO is used to achieve an array pattern with minimum side lobe level (SLL) along with null placement in the specified directions. GWO is also applied for the minimization of the first side lobe nearest to the main beam (near side lobe). Various examples are presented that illustrate the application of GWO for linear array optimization and, subsequently, the results are validated by benchmarking with results obtained using other state-of-the-art nature-inspired evolutionary algorithms. The results suggest that optimization of linear antenna arrays using GWO provides considerable enhancements compared to the uniform array and the synthesis obtained from other optimization techniques.

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Xu, Haiyun, Weijia Cui, Fengtong Mei, Bin Ba, and Chunxiao Jian. "The Design of A Novel Sparse Array Using Two Uniform Linear Arrays considering Mutual Coupling." Journal of Sensors 2021 (August 17, 2021): 1–15. http://dx.doi.org/10.1155/2021/9934097.

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The sparse arrays using two uniform linear arrays have attracted considerable interest due to the capability of giving analytical expression of sensor location and owning robust direction-of-arrival (DOA) facing strong mutual coupling and sensor failure. In order to achieve the maximum consecutive virtual uniform linear array in difference coarray, in this paper, a design method of a novel sparse array using two uniform linear arrays (NSA-U2) is proposed. We first analyze the relationship between the values of displacement of two subarrays and difference coarray, and then we give the analytical expressions of the displacement and the number of consecutive lags. By discussing the selection of number of subarray sensors, the design of NSA-U2 is completed. Moreover, through choosing a proper compressed interelement spacing, NSA-U2 can be robust to mutual coupling effect. Numerical experiments prove the effectiveness and favorable performance of DOA estimation with mutual coupling.

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Maldonado, Gonzalo, Alberto Reyna Maldonado, Luz I. Balderas, and Marco A. Panduro. "Time-Modulated Antenna Arrays for Ultra-Wideband 5G Applications." Micromachines 13, no. 12 (2022): 2233. http://dx.doi.org/10.3390/mi13122233.

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This research presents the design of time-modulated antenna arrays with UWB performance. The antenna arrays consider a linear topology with eight UWB disk-notch patch antennas. The technological problem is to find out the optimum antenna positions and/or time sequences to reduce the side lobes and the sidebands in all of the UWB frequency ranges. The design process is formulated as a bacterial foraging optimization. The results show that the uniform array generates a better SLL performance whereas the non-uniform array obtains a wider bandwidth. The uniform array obtains an SLL < −20 dB from 3.37 GHz to 4.8 GHz and the non-uniform array generates an SLL < −7 dB from 2.97 GHz to 5.26 GHz. The sideband levels are very similar for both cases with a value of around −17 dB.

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Singh, Satyanand. "Minimal Redundancy Linear Array and Uniform Linear Arrays Beamforming Applications in 5G Smart Devices." Emerging Science Journal 4 (October 6, 2021): 70–84. http://dx.doi.org/10.28991/esj-2021-sp1-05.

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Minimum Redundancy Linear Arrays (MRLAs) and Uniform Linear Arrays (ULAs) investigation conducted with the possibility of using them in future 5G smart devices. MRLAs are designed to minimize the number of sensor pairs with the same spatially correlated delay. It eliminates selected antennas from the entire composite antenna array and preserves all possible antenna spacing. MRLAs have attractive features for linear sparse arrays, even if the built-in surface is deformed, it works without problems. To our knowledge, MRLAs have not been applied to smart devices so far. In this work, a 7-element ULAs and 4-element MRLAs (same aperture) were used for the simulation. The Half Power Beamwidth (HPBW) is 0.666 and the Null-to-Null Beamwidth ( ) is 1.385 in ψ-space. In comparison, the standard 4-element arrays are 1.429 and 3.1416, while the standard 7-element linear arrays are 0.801 and 1.795 respectively. Experimental results show that 4-element MLRAs have a narrower mean beam, much higher sidelobes and shallow nulls. Therefore, in terms of main lobe features, 4- elements MRLAs have an improvement over the standard 7-element ULAs. Doi: 10.28991/esj-2021-SP1-05 Full Text: PDF

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Sun, Muye, and Tianyu Duanmu. "DOA estimation technology based on array signal processing nested array." Applied and Computational Engineering 64, no. 1 (2024): 23–29. http://dx.doi.org/10.54254/2755-2721/64/20241345.

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Research on non-uniform arrays has always been a focus of attention for scholars both domestically and internationally. Part of the research concentrates on existing non-uniform arrays, while another part focuses on optimizing the position of array elements or expanding the structure. Of course, there are also studies on one-dimensional and two-dimensional DOA estimation algorithms based on array spatial shapes, despite some issues. As long as there is a demand for spatial domain target positioning, the development and refinement of non-uniform arrays will continue to be a hot research direction. Nested arrays represent a unique type of heterogeneous array, whose special geometric shape significantly increases degrees of freedom and enhances estimation performance for directional information of undetermined signal sources. Compared to other algorithms, the one-dimensional DOA estimation algorithm based on spatial smoothing simplifies algorithm complexity, improves estimation accuracy under nested arrays, and can effectively handle the estimation of signal sources under uncertain conditions. The DFT algorithm it employs not only significantly improves angular estimation performance but also reduces operational complexity, utilizing full degrees of freedom to minimize aperture loss. Furthermore, the DFT-MUSIC method greatly reduces algorithmic computational complexity while performing very closely to the spatial smoothing MUSIC algorithm. The sparse arrays it utilizes, including minimum redundancy arrays, coprime arrays, and nested arrays, are a new type of array. Sparse arrays can increase degrees of freedom compared to traditional uniform linear arrays and solve the estimation of signal source angles under uncertain conditions, while also enhancing algorithm angular estimation performance.

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Cheng, Chi-Hao. "A Sub-Nyquist Uniform Linear Array Receiver Design." IEEE Access 9 (2021): 114359–66. http://dx.doi.org/10.1109/access.2021.3104853.

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Su, Qiao, Yuehong Shen, Yimin Wei, Changliang Deng, and Linyuan Zhang. "SSP-Based UBI Algorithms for Uniform Linear Array." Circuits, Systems, and Signal Processing 36, no. 10 (2017): 4077–96. http://dx.doi.org/10.1007/s00034-017-0500-2.

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Deng, Wei Bo, Hong Xin Sun, Ying Ning Dong, and Qiang Yang. "Optimal Design of Non-Uniform Linear Array Using Genetic Algorithm." Applied Mechanics and Materials 556-562 (May 2014): 3686–91. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3686.

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An arrangement method for non-uniform linear array using genetic algorithm (GA) is proposed. It is a general purpose method and needs only the angle range of the signal directions and the desired aperture of the array. It has few parameters, simple processing steps and a strong stabilization. It can be applied to optimize arbitrary array configuration. Modified multiple signal classification (MMUSIC) algorithm is discussed for estimating coherent sources using the non-uniform linear array. Simulation results show that the performance of the direction of arrival (DOA) estimation has been improved effectively on contrast with other array structures, the validity of the proposed method is proved.

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Mohammed, Amine Ihedrane, and Bri Seddik. "Direction of Arrival Using Uniform Circular Array Based on 2-D MUSIC Algorithm." Indonesian Journal of Electrical Engineering and Computer Science 12, no. 1 (2018): 30–37. https://doi.org/10.11591/ijeecs.v12.i1.pp30-37.

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This study presents the conception, simulation, realisation and characterisation of a patch antenna for Wi-Fi. The antenna is designed at the frequency of 2.45 GHz; the dielectric substrate used is FR4_epoxy which has a dielectric permittivity of 4.4.this patch antenna is used to estimate the direction of arrival (DOA) using 2-D Multiple Signal Classification (2-D MUSIC) the case of the proposed uniform circular arrays (UCA). The comparison between Uniform circular arrays and Uniform Linear arrays (ULA) demonstrate that the proposed structure give better angles resolutions compared to ULAs.

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Park, Yongsung, and Peter Gerstoft. "Alternating projections-based gridless compressive beamforming with co-prime arrays." Journal of the Acoustical Society of America 152, no. 4 (2022): A143. http://dx.doi.org/10.1121/10.0015834.

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Direction-of-arrivals (DOAs) estimation, beamforming, retrieves the angles of several sources from the outputs of receiving a sensor array. Compressive beamforming is a sparse signal recovery approach and has shown superior performance on DOA estimation. To overcome the angular searching grid issue, gridless techniques have been proposed. Most methods require a uniform linear array and use standard convex solvers that are computationally expensive. We propose a gridless compressive beamformer based on alternating projections. This method estimates DOAs by projecting a solution matrix alternatively. One projection works for measured-data-fitting, and the other works for having sparse DOAs. Our approach improves speed and accuracy and deals with arbitrary-shaped linear arrays. We validate the method using experimental data and test the DOA performance for a single snapshot, multiple snapshots with coherent arrivals, and co-prime arrays, a well-known non-uniform array.

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Riabko, Andrii, Tetiana Vakaliuk, Oksana Zaika, Roman Kukharchuk, and Yuriy Smorzhevsky. "Comparative analysis and selection of the geometry of the microphone array based on MEMS microphones for sound localisation." Radioelectronic and Computer Systems 2025, no. 1 (2025): 211–30. https://doi.org/10.32620/reks.2025.1.15.

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The subject of this article is the design and optimization of the geometric configuration of omnidirectional MEMS microphone arrays for sound localization tasks. The goal is to determine the most effective array architecture and beamforming algorithms to achieve compactness, accuracy, and balanced omnidirectional coverage. The tasks to be addressed include analyzing spatial-frequency characteristics of various microphone array geometries (Uniform Linear Array, Uniform Planar Array, Uniform Circular Array, and Uniform Concentric Array), comparing beamforming algorithms (delay-and-sum, differential, and superdirective), and evaluating their performance under isotropic noise fields and coherent noise sources. The methods used involve the application of both established and author-derived analytical models for transfer functions and directivity coefficients, as well as experimental validation using a prototype device built on a Raspberry Pi 5 platform with an Adafruit PCA9548 8-Channel STEMMA QT expansion board and SPH0645LM4H-B omnidirectional MEMS microphones. The results show that similar geometric configurations of microphone arrays from omnidirectional microphones can be used for sound localization tasks at low frequencies because they are characterized by good values of Array Directivity and HPBW. This means creating a sufficiently narrow main beam, where the level of the sidelobe SLL does not differ from that of the main lobe at high frequencies. The best configurations were URA Microphone Arrays with n = 8 and d = 23 cm. Conclusions. Differential beamforming algorithms have demonstrated superior performance in isolation of target signals in challenging acoustic environments. The Uniform Circular Array (UCA) combined with DAS or EF DAS algorithms provides reliable omnidirectional coverage and balanced frequency response, making it ideal for applications requiring uniform sensitivity. Optimizing the spacing and radius of the microphone arrays further enhances directivity and minimizes sidelobe levels. In future work, we will focus on improving array designs using SSL reduction methods to expand localization accuracy across a wider frequency range.

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Razzak, Atteeq, Tehseen Rahim, and Azeem Razzak. "On-Board Wide Broad Bandwidth Switching Linear and Planar Antenna Arrays for Industrial Use in an Era of Industrial Revolution." International Journal of Circular Economy and Waste Management 2, no. 2 (2022): 1–11. http://dx.doi.org/10.4018/ijcewm.306210.

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The paper outlines the analysis of horn antenna and arrays of microstrip antenna for onboard high data rate transmission in the X-Band ( 10 Ghz). The antenna arrays consists of eight equispaced linear array elements with beam formation and gain of 20 dB. In satellite communication, we require the transmission of waves which are circularly polarized. This is achieved by placing helical antenna elements, which has the advantage that the antenna is broadband and transmission is circularly polarized. This paper also considers method of feeding the linear array, where only a first few elements produce radiation and the pattern is highly distorted. Linear array feed from both ends will produce uniform excitation so that the entire array is excited, with low distortion of pattern.

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Ifeoma, B. Asianuba. "Side Lobe Reduction in Linear Array Antenna using Numerical Computation Approach." European Journal of Advances in Engineering and Technology 6, no. 4 (2019): 29–35. https://doi.org/10.5281/zenodo.10687581.

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<strong>ABSTRACT</strong> Large amount of energy is saved when a transmitting antenna propagates its field radiations painstakingly in the required direction of propagation. For this reason, reduction in side lobe radiation is essential to avoid degrading the total power and efficiency of the radiating structure. In this paper, a numerical approach is adopted other than the well known stochastic approach to reduce side lobe radiations in linear array antennas. This choice is as a result of the short design cycle of the numerical solution for antenna field problems, full exploration of design space and provision of large physical insights on the design output. The parameters of the array antenna are deployed in the reduction of the side lobe radiations. These include; non-uniform inter-element spacing, non-uniform excitation amplitude and varying number of antenna elements. Radiation patterns for linear array antenna with non-uniform characteristics are generated from the simulation result. The patterns with the least side lobe and beam width are determined. This outcome ensures signals are not transmitted in undesirable directions and efficient communication process can be guaranteed. 

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Li, Ying, and Gong Zhang. "2D-DOA Estimation for MIMO Radar on Monostatic L-Shaped Minimum-Redundancy Linear Arrays." Advanced Materials Research 926-930 (May 2014): 2871–75. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.2871.

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This paper discussed the problem of two dimensional (2D) direction of arrival (DOA) estimation for multi-input multi-output (MIMO) radar. The minimum-redundancy linear array (MLRA) is introduced into the transmitting array and receiving array, which enables the high efficiency of the radar system. By utilizing the algorithm of multiple signal classification (MUSIC), we illustrate that the proposed scheme performs better than the uniform linear arrays (ULA) configuration under the same conditions. Simulation results verify the effectiveness of our scheme.

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Liu, Sheng, Jing Zhao, and Yu Zhang. "2D DOA Estimation with a Two-Parallel Array Consisting of Two Uniform Large-Spacing Linear Arrays." International Journal of Antennas and Propagation 2020 (April 30, 2020): 1–8. http://dx.doi.org/10.1155/2020/4069307.

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In this paper, an improved propagator method (PM) is proposed by using a two-parallel array consisting of two uniform large-spacing linear arrays. Because of the increase of element spacing, the mutual coupling between two sensors can be reduced. Firstly, two matrices containing elevation angle information are obtained by PM. Then, by performing EVD of the product of the two matrices, the elevation angles of incident signals can be estimated without direction ambiguity. At last, the matrix product is used again to obtain the estimations of azimuth angles. Compared with the existed PM algorithms based on conventional uniform two-parallel linear array, the proposed PM algorithm based on the large-spacing linear arrays has higher estimation precision. Many simulation experiments are presented to verify the effect of proposed scheme in reducing the mutual coupling and improving estimation precision.

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Lang, Rongling, Hao Xu, and Fei Gao. "Robust Direction Estimation of Terrestrial Signal via Sparse Non-Uniform Array Reconfiguration under Perturbations." Remote Sensing 16, no. 18 (2024): 3482. http://dx.doi.org/10.3390/rs16183482.

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DOA (Direction of Arrival), as an important observation parameter for accurately locating the Signals of Opportunity (SOP), is vital for navigation in GNSS-challenged environments and can be effectively obtained through sparse arrays. In practical application, array perturbations affect the estimation accuracy and stability of DOA, thereby adversely affecting the positioning performance of SOP. Against this backdrop, we propose an approach to reconstruct non-uniform arrays under perturbation conditions, aiming to improve the robustness of DOA estimation in sparse arrays. Firstly, we theoretically derive the mathematical expressions of the Cramér–Rao Bound (CRB) and Spatial Correlation Coefficient (SCC) for the uniform linear array (ULA) with perturbation. Then, we minimize CRB as the objective function to mitigate the adverse effects of array perturbations on DOA estimation, and use SCC as a constraint to suppress sidelobes. By doing this, the non-uniform array reconstruction model is formulated as a high-order 0–1 optimization problem. To effectively solve this nonconvex model, we propose a polynomial-time algorithm, which can converge to the optimal approximate solution of the original model. Finally, through a series of simulation experiments utilizing frequency modulation (FM) signal as an example, the exceptional performance of this method in array reconstruction has been thoroughly validated. Experimental data show that the reconstructed non-uniform array excels in DOA estimation accuracy compared to other sparse arrays, making it particularly suitable for estimating the direction of terrestrial SOP in perturbed environments.

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31

Patwari, Ashish, and G. Ramachandra Reddy. "A Conceptual Framework for the Use of Minimum Redundancy Linear Arrays and Flexible Arrays in Future Smartphones." International Journal of Antennas and Propagation 2018 (September 18, 2018): 1–12. http://dx.doi.org/10.1155/2018/9629837.

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This work applies existing array processing principles to devise a new area of application. The properties of minimum redundancy linear arrays (MRLAs) and flexible arrays are studied, keeping in mind the possibility of using them in flexible 5G smartphones of the future. Millimeter frequencies for 5G communications enabled the use of a decent number of array elements, even at the user equipment (UE). MRLAs possess attractive properties among linear sparse arrays and flexible conformal arrays (flexible arrays) operate satisfactorily even when the surface they are built into changes shape. To the best of our knowledge, MRLAs were not applied to smartphones previously. In this work, a 16-element uniform linear array (ULA) and a 7-element MRLA (with the same aperture) are considered for simulations. Array factors of both the arrays in flat and bent positions have been computed using MATLAB. The effect of phase compensation and bending radii on the array pattern were verified. That phase compensation using the projection method (PM) restores the array pattern even for a bent MRLA is a major finding. Possible array processing modes have been suggested for a 5G smartphone in which the array could be made to operate in any of the four configurations: a flat ULA, a bent ULA, a flat MRLA, and a bent MRLA.

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Tsai, J. A., R. M. Buehrer, and B. D. Woerner. "BER Performance of a Uniform Circular Array Versus a Uniform Linear Array in a Mobile Radio Environment." IEEE Transactions on Wireless Communications 3, no. 3 (2004): 695–700. http://dx.doi.org/10.1109/twc.2004.826332.

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Kenane, El Hadi, and Farid Djahli. "Optimum design of non-uniform symmetrical linear antenna arrays using a novel modified invasive weeds optimization." Archives of Electrical Engineering 65, no. 1 (2016): 5–18. http://dx.doi.org/10.1515/aee-2016-0001.

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Abstract This paper presents a new modified method for the synthesis of non-uniform linear antenna arrays. Based on the recently developed invasive weeds optimization technique (IWO), the modified invasive weeds optimization method (MIWO) uses the mutation process for the calculation of standard deviation (SD). Since the good choice of SD is particularly important in such algorithm, MIWO uses new values of this parameter to optimize the spacing between the array elements, which can improve the overall efficiency of the classical IWO method in terms of side lobe level (SLL) suppression and nulls control. Numerical examples are presented and compared to the existing array designs found in the literature, such as ant colony optimization (ACO), particle swarm optimization (PSO), and comprehensive learning PSO (CLPSO). Results show that MIWO method can be a good alternative in the design of non-uniform linear antenna array.

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Chang, Lin, Hao Zhang, Hua Yang, Tingting Lv, and Ning Tang. "Virtual covariance matrix reconstruction-based adaptive beamforming for small aperture array." PLOS ONE 18, no. 10 (2023): e0293012. http://dx.doi.org/10.1371/journal.pone.0293012.

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Recently, many robust adaptive beamforming (RAB) algorithms have been proposed to improve beamforming performance when model mismatches occur. For a uniform linear array, a larger aperture array can obtain higher array gain for beamforming when the inter-sensor spacing is fixed. However, only the small aperture array can be used in the equipment limited by platform installation space, significantly weakening beamforming output performance. This paper proposes two beamforming methods for improving beamforming output in small aperture sensor arrays. The first method employs an integration algorithm that combines angular sector and gradient vector search to reconstruct the interference covariance matrix (ICM). Then, the interference-plus-noise covariance matrix (INCM) is reconstructed combined with the estimated noise power. The INCM and ICM are used to optimize the desired signal steering vector (SV) by solving a quadratically constrained quadratic programming (QCQP) problem. The second method proposes a beamforming algorithm based on a virtual extended array to increase the degree of freedom of the beamformer. First, the virtual conjugated array element is designed based on the structural characteristics of a uniform linear array, and received data at the virtual array element are obtained using a linear prediction method. Then, the extended INCM is reconstructed, and the desired signal SV is optimized using an algorithm similar to the actual array. The simulation results demonstrate the effectiveness of the proposed methods under different conditions.

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Abdalmalak, Kerlos Atia, Ayman Abdulhadi Althuwayb, Choon Sae Lee, et al. "Standing-Wave Feeding for High-Gain Linear Dielectric Resonator Antenna (DRA) Array." Sensors 22, no. 8 (2022): 3089. http://dx.doi.org/10.3390/s22083089.

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A novel feeding method for linear DRA arrays is presented, illuminating the use of the power divider, transitions, and launchers, and keeping uniform excitation to array elements. This results in a high-gain DRA array with low losses with a design that is simple, compact and inexpensive. The proposed feeding method is based on exciting standing waves using discrete metallic patches in a simple design procedure. Two arrays with two and four DRA elements are presented as a proof of concept, which provide high gains of 12 and 15dBi, respectively, which are close to the theoretical limit based on array theory. The radiation efficiency for both arrays is about 93%, which is equal to the array element efficiency, confirming that the feeding method does not add losses as in the case of standard methods. To facilitate the fabrication process, the entire array structure is 3D-printed, which significantly decreases the complexity of fabrication and alignment. Compared to state-of-the-art feeding techniques, the proposed method provides higher gain and higher efficiency with a smaller electrical size.

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Wang, Jian Rong, Ju Zhang, Song Gun Hyon, and Jian Guo Wei. "Sound Source Localization Based on Microphone Uniform Linear Array." Advanced Materials Research 748 (August 2013): 634–39. http://dx.doi.org/10.4028/www.scientific.net/amr.748.634.

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In order to locate the sound source based on the microphone uniform linear array and reduce the impact of noise and reflection, improved multiple signal classification algorithm and a kind of weighted average filters be used in this paper. According to the microphone array speech processing characteristics, we improved the traditional multiple signal classification algorithm and designed a kind of weighted average filters. Then, we made the computer simulation experiments. The experimental results show that the location of the sound source is the peak with the highest power in the spatial spectrum. Besides, the frequency domain diagram is more smoothly and the power of the noise and reflection is effectively reduced except sound source through the weighted average processing. Therefore, improved multiple signal classification algorithm can achieve sound source localization based on the microphone uniform linear array. And the impact of the noise and reflection is effectively reduced by processing of the weighted average filters.

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JHANG, Wei, Shiaw-Wu CHEN, and Ann-Chen CHANG. "Efficient Hybrid DOA Estimation for Massive Uniform Linear Array." IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E102.A, no. 5 (2019): 721–24. http://dx.doi.org/10.1587/transfun.e102.a.721.

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Cao, Xiang, Jingmin Xin, Yoshifumi Nishio, and Nanning Zheng. "Spatial Signature Estimation with an Uncalibrated Uniform Linear Array." Sensors 15, no. 6 (2015): 13899–915. http://dx.doi.org/10.3390/s150613899.

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JHANG, Wei, Shiaw-Wu CHEN, and Ann-Chen CHANG. "Computationally Efficient DOA Estimation for Massive Uniform Linear Array." IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E103.A, no. 1 (2020): 361–65. http://dx.doi.org/10.1587/transfun.2019eal2107.

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Zhang, Ying, Guang Yao Xin, and Xiao Fei Zhang. "DOA Estimation for Uniform Linear Array with Compressive Sensing." Applied Mechanics and Materials 713-715 (January 2015): 1239–43. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1239.

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This paper discusses that the application of compressive sensing in direction of arrival (DOA) estimation. Traditional DOA estimation algorithms, such as MUSIC, ESPRIT, have shortcomings of high demand of initialization and sufficient number of snapshots and high sensitivity to signal-to-noise ratio (SNR). The proposed DOA estimation algorithm via OMP method based on compressed sensing (CS) can solve the above-mentioned problem and has good estimation performance. Computer simulations verify the effectiveness of the OMP algorithm.

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Elbarbary, K., and E. Azzouz. "SUPPRESSION OF COHERENT INTEREFERENCES USING UNIFORM LINEAR ANTENNA ARRAY." International Conference on Aerospace Sciences and Aviation Technology 10, ASAT CONFERENCE (2003): 1–10. http://dx.doi.org/10.21608/asat.2013.24694.

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Zhongfu Ye, Jisheng Dai, Xu Xu, and Xiaopei Wu. "DOA Estimation for Uniform Linear Array with Mutual Coupling." IEEE Transactions on Aerospace and Electronic Systems 45, no. 1 (2009): 280–88. http://dx.doi.org/10.1109/taes.2009.4805279.

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Huang, Long Yang, and Wei Jun Pan. "Synthesizing Pattern with Broad Nulls through Orthogonal Method." Advanced Materials Research 121-122 (June 2010): 992–95. http://dx.doi.org/10.4028/www.scientific.net/amr.121-122.992.

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Based on the Gram-Schmidt orthogonalization method utilized for pattern synthesis of linear array without constraints, null derivative constraints are proposed to implement pattern synthesis with broad nulls. The advantage of the simplified computation resulted from steering vector orthogonalization in unconstrained orthogonal approach is maintained, and the uniform or non-uniform linear array pattern synthesis can be realized by this method. The experimental results show that the null constrained orthogonal approach can fulfill linear array pattern synthesis with constrains such as null constrains, first-order and second-order derivative null constraints.

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Khan, Waseem, Saleem Shahid, Waleed Iqbal, et al. "Semi-Coprime Array with Staggered Beam-Steering of Sub-Arrays." Sensors 23, no. 12 (2023): 5484. http://dx.doi.org/10.3390/s23125484.

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A split-aperture array (SAA) is an array of sensors or antenna elements in which the array is split into two or more sub-arrays (SAs). Recently proposed SAAs, namely coprime and semi-coprime arrays, offer to attain a small half-power beamwidth (HPBW) with a small number of elements, compared to most conventional unified-aperture arrays, at the cost of reduced peak-to-side-lobe ratio (PSLR). To reduce HPBW and increase PSLR, non-uniform inter-element spacing and excitation amplitudes have proven helpful. However, all the existing arrays and beam-formers suffer increased HPBW, degraded PSLR or both when the main beam is steered away from the broadside. In this paper, we propose staggered beam-steering of SAs, a novel technique for decreasing HPBW. In this technique, we steer the main beams of the SAs of a semi-coprime array to angles slightly different from the desired steering angle. In conjunction with staggered beam-steering of SAs, we have utilized Chebyshev weights to suppress the side lobes. The results show that the beam-widening effect of Chebyshev weights can be mitigated considerably by staggered beam-steering of the SAs. Ultimately, the unified beam-pattern of the whole array offers HPBW and PSLR better than the existing SAAs, uniform and non-uniform linear arrays, especially when the desired steering angle is away from the broadside direction.

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XIE, Lei, and Chao SUN. "Array gain of a horizontal uniform linear array in the continental shelf slope." SCIENTIA SINICA Physica, Mechanica & Astronomica 46, no. 9 (2016): 094308. http://dx.doi.org/10.1360/sspma2016-00123.

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Rahiman Sheik, Abdul, and Dr Kalva Sri Rama Krishna. "Constrained synthesis of the Linear Antenna Array using Social Group Optimization." International Journal of Engineering & Technology 7, no. 2.17 (2018): 105. http://dx.doi.org/10.14419/ijet.v7i2.17.11568.

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In this paper, novel algorithm known as social group optimization is use for array synthesis problem. The algorithm is implemented to the electromagnetic problem solving and its performance is evaluated. The array design is carried out with the objective of sidelobe level (SLL) suppression with uniform beam width (BW) constraint. The amplitude only technique is used to determine the coefficients of current excitation which produce the desired radiation pattern with the objectives and constraints. The analysis is carried out in terms of radiation pattern for different length of linear arrays. The simulation based experimentation is carried out in Matlab.

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Wang, Chen, and Hao Huan. "A Novel Nested Array Structure for DOA Based on CCM of Subarrays." Journal of Physics: Conference Series 2625, no. 1 (2023): 012057. http://dx.doi.org/10.1088/1742-6596/2625/1/012057.

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Abstract An innovative nested array structure that can notably increase the DOF and the linear arrays’ direction of arrival (DOA) estimated performance is proposed. For the conventional nested array, we vectorize the ACM’s output of the whole array and then remove the repeated rows to get a virtual array’s output. In contrast with classical nested arrays, the superiority of the new nested array is that it utilizes the combination of reverse ordering and conjugation of the inner uniform linear array (ULA) for one of the two subarrays and the sparse outer ULA for another to increase the array aperture. This means the outer sparse ULA’s sensor spacing is approximately the length of the entire inner ULA in the classical nested array structure. Yet, it is about twice the length in the new nested array structure. We generate one lengthy consecutive virtual uniform array excluding any redundant virtual sensors by vectorizing the two subarrays’ cross-correlation matrix (CCM), which is mentioned above. With the export signal of the virtual array and its conjugate form of it, an equivalent covariance matrix of full rank is constructed, which is called the Toeplitz matrix, to compensate for the rank lack of the virtual array’s ACM. For the sake of obtaining the DOA of input signals, the conventional DOA estimation method will be implemented on the ACM. The increase in outer sparse ULA’s sensor spacing ensures an increase in virtual array aperture in principle, which means it is capable of increasing the number of DOA estimations, which is called DOF, and optimizing the DOA estimated performance in contrast with the ULA and classical nested arrays. Results from trials certify the preponderance of the proposed structure in the aspect of DOF and the accuracy of DOA estimation.

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Chung, Hyeonjin, Jeungmin Joo, and Sunwoo Kim. "Off-Grid DoA Estimation on Non-Uniform Linear Array Using Constrained Hermitian Matrix." Energies 13, no. 21 (2020): 5775. http://dx.doi.org/10.3390/en13215775.

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In this paper, an off-grid direction-of-arrival (DoA) estimation algorithm which can work on a non-uniform linear array (NULA) is proposed. The original semidefinite programming (SDP) representation of the atomic norm exploits a summation of one-rank matrices constructed by atoms, where the summation of one-rank matrices equals a Hermitian Toeplitz matrix when using the uniform linear array (ULA). On the other hand, when the antennas in the array are placed arbitrarily, the summation of one-rank matrices is a Hermitian matrix whose diagonal elements are equivalent. Motivated by this property, the proposed algorithm replaces the Hermitian Toeplitz matrix in the original SDP with the constrained Hermitian matrix. Additionally, when the antennas are placed symmetrically, the performance can be enforced by adding extra constraints to the Hermitian matrix. The simulation results show that the proposed algorithm achieves higher estimation accuracy and resolution than other algorithms on both array structures; i.e., the arbitrary array and the symmetric array.

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WANG, Na, Xuanzhi ZHAO, Zengli LIU, and Jingjing ZHANG. "DOA estimation method of spatial spectrum product for distributed coprime linear array." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, no. 5 (2021): 1130–38. http://dx.doi.org/10.1051/jnwpu/20213951130.

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Coprime array isAsparse array composed of two uniform linear arrays with different spacing. When the two subarrays are inAnon-coherent distributed configuration, the direction of arrival (DOA) method based on the covariance analysis of the complete coprime array is no longer effective. According to the essential attribute that the distance between the elements of two subarrays can eliminate the angle ambiguity, based on the mathematical derivation, Aspatial spectral product DOA estimation method for incoherent distributed coprime arrays is proposed. Firstly, the spatial spectrum of each subarray is calculated by using the snapshot data of each subarray, and then the DOA estimation is realized by multiplying the spatial spectrum of each subarray. The simulation results show that the estimation accuracy and angle resolution of the present method are better than those of the traditional ambiguity resolution methods, and the estimation performance is good in the mutual coupling and low SNR environment, with the good adaptability and stability. Moreover, by using the flexibility of distributed array, the matching error is effectively solved through the rotation angle.

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Sun, Li-juan, Zhen-kai Zhang, and Hamid Esmaeili Najafabadi. "Shared Aperture Multibeam Forming of Time-Modulated Linear Array." Complexity 2019 (November 26, 2019): 1–10. http://dx.doi.org/10.1155/2019/4101909.

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A novel technique is proposed in this paper for shared aperture multibeam forming in a complex time-modulated linear array. First, a uniform line array is interleaved randomly to form two sparse array subarrays. Subsequently, the theory of time modulation for linear arrays is applied in the constructed subarrays. In the meantime, the switch-on time sequences for each element of the two subarrays are optimized by an optimized differential evolution (DE) algorithm, i.e., the scaling factor of the sinusoidal iterative chaotic system and the adaptive crossover probability factor are used to enhance the diversity of the population. Lastly, the feasibility of the new technique is verified by the comparison between this technique and the basic multibeam algorithm in a shared aperture and the algorithm of iterative FFT. The results of simulations confirm that the proposed algorithm can form more desired beams, and it is superior to other similar approaches.

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Journal articles on the topic 'Uniform Linear Array'

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