1,721,001 research outputs found
A Synthesis Technique for the Beam Scanning with Aperiodic Arrays
No full textThis paper proposes a method to find the optimal positions of the elements of a linear aperiodic array, with the aim of performing the scanning of the beam in an angular region of interest, by phase-only control. A recently proposed Gaussian approach is adopted, in which the desired pencil beam is approximated by a Gaussian function. By a proper formulation of the problem, the element positions are synthesized in closed form, so as to perform a continuous beam scanning by suitably modifying only the excitation phases. The amplitude distribution of the array elements is uniform, so that the feeding network is simple to realize, and the mutual coupling effects are reduced. © 2019 European Association on Antennas and Propagation
Gaussian approach for the synthesis of phase-only beam-scanning linear aperiodic antenna arrays
Full text linkThis paper describes a method for the synthesis of linear aperiodic antenna arrays with beam scanning capability. The algorithm is based on a recently proposed Gaussian approach, regarding linear aperiodic arrays of isotropic elements with uniform amplitude distribution, which yields the optimal element positions of the array in such a way as to form a Gaussian beam of prescribed properties. The latter approach is here extended to solve a problem of beam scanning in an angular region of interest. Precisely, the array element positions are determined in such a way as to form a pencil beam, that can be pointed in any direction of the angular region of interest by a suitable distribution of the excitation phases. Thus, a continuous beam scanning can be performed by phase-only control. It is also shown that the alternating projection approach can mitigate the pattern degradation that arises for pointing angles near the end-fire direction
Compressive sensing approach to the synthesis of sparse antenna arrays
No full textThe Compressive Sensing (CS) technique, first introduced in the field of image processing, is nowadays used in many engineering problems. Electromagnetics counts a number of problems which have been solved with a suitable CS-based strategy, such as, for examples, the diagnosis and synthesis of antenna arrays, the estimation of directions of arrival, and the solution of inverse scattering and radar imaging problems. This paper presents an overview of some algorithms based on the CS approach, recently developed by the authors for the synthesis of sparse antenna arrays, also including additional constraints
Design of a Simple Feeding Network for 5G Multidirectional Antennas
Full text linkMultidirectional antennas are one of the enabling technologies for the widespread diffusion of intelligent vehicles, which are expected to fill smart cities in the near future characterized by the fifth generation cellular system (5G). In this context, this paper proposes a simple and versatile design procedure for a feeding network that realizes the beam steering of linear antenna arrays. The developed procedure is intended for a feedline, which must meet some requirements typical in a 5G scenario, such as, for example, easy mass production, low cost, easy integration with other system components and compactness. Precisely, a Blass matrix using the microstrip technology and identical branch line directional couplers is implemented so that the multidirectional antenna system can be entirely printed on a compact and cheap printed circuit board (PCB). However, when the coupling value is fixed in advance some pointing directions may be not realizable. So, this paper proposes an algorithm, which evaluates a desired number of beams in such a way to have a simple design procedure of a feeding network for a multidirectional linear antenna array. The effectiveness of the developed solution is validated by numerical result
Gaussian approach versus Dolph-Chebyshev synthesis of pencil beams for linear antenna arrays
Full text linkA very simple and fast method for the synthesis of pencil beams with linear antenna arrays of equally spaced elements is presented. The proposed procedure starts selecting the desired pencil beam as a Gaussian function. This is very convenient for two reasons: first, the continuous line-source distribution that exactly produces the desired pencil beam (i.e. the Fourier transform of it) is in turn a Gaussian function and is immediately calculated. Second, a suitable weighted sampling of this distribution gives the excitations of the array elements in closed form. Two numerical examples reveal the good performances of the proposed approach, also in comparison with the classical method by Dolph-Chebyshev. It is shown that the synthesised array factors well approximate the desired pencil beams in real time, in particular ensuring a very good behaviour in the side lobe regions. Furthermore, the ‘dynamic range ratio’ of the excitations, defined as the ratio between the maximum and the minimum amplitude of the excitations, is very low and close to unity when the array length is sufficiently small
On the Design of a Circularly Polarized Microstrip Antenna Array for CubeSat in the Ka-Band
No full textThis paper describes the preliminary phases of the design of a planar antenna array to be mounted on a face of a CubeSat operating in the Ka-frequency band. In order to compensate the high attenuation of the millimeter-waves, the antenna is required to be circularly polarized, and the final array is composed of subarrays of sequentially rotated square microstrip patches with truncated corners. In particular, two candidate geometries are presented for the subarray, which improve a prototype previously realized at the University of Trieste. Then, the performances of three possible configurations for the final array are evaluated. © 2019 European Association on Antennas and Propagation
Phase-Only reconfigurable aperiodic arrays
No full textIn this paper a deterministic procedure is presented for the synthesis of phase-only reconfigurable aperiodic arrays. The proposed approach develops in three steps: at first, one aperiodic array for each of the desired patterns is derived, then a unique aperiodic geometry is suitably selected, and finally a deterministic phase-only synthesis algorithm is applied to the latter aperiodic array, in order to determine suitable excitation phases and to achieve reconfigurability. Although the optimality of the solution is not guaranteed, a numerical example is proposed to test the method
Pencil Beam Constrained Synthesis of Linear Sparse Arrays in Presence of Coupling Effects
No full textIn this work an efficient method is presented for the pencil beam constrained synthesis of linear sparse arrays. As a first step, the positions of a number of isotropic radiators are found on an aperture of given length. Then, the isotropic radiators are replaced with real antenna elements, and the excitations are optimized in such a way that, taking the mutual coupling into account, the radiation pattern belong to a prescribed mask. Two numerical examples show the effectiveness of the proposed approach
Fast 3D Synthesis of Aperiodic Rectangular Arrays
No full textWe propose a fast and simple method to generate a 3D pencil beam with a sparse array of elements having uniform excitations and located on a rectangular grid. The presented algorithm extends a recently proposed Gaussian approach, introducing a desired pattern as the product of two suitable Gaussian functions. This reduces the problem to a couple of independent one-dimensional problems, and the optimal positions of the array elements are found in closed form. Numerical examples show the effectiveness of the method
3D Millimeter-Wave Peer-to-Peer Networks With Boundary Located Destination
Full text linkThis letter presents a theoretical analysis for estimating the coverage probability and the average link capacity of an interfered peer-to-peer millimeter-wave communication, when the destination lies at the boundary of a three-dimensional cell. The proposed model provides closed-form expressions for the statistics of the desired and undesired signal powers, by accounting for the impact of directional antenna gains, path-loss attenuation, mid-scale fading, interference, and noise
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