This study presents a 5G antenna array for millimetre-wave communications. Overall size of the proposed antenna array is 40 × 15 mm2, and operates in a measured 23.76–42.15 GHz frequency range. A ...planar four-way feed network has been designed, optimised and used to excite the antenna array elements. The single element of the array is spiral monopole surrounded by a boundary of vias with extended ground plane in an inverted U-shaped manner. Hexagonal parasitic patches have been introduced at the backside to enhance impedance performance of the antenna element. Peak gain of the proposed antenna array is 11.5 dBi with radiation efficiency more than 83% in its entire operating band. The antenna gives a narrow beam-width of as low as 10.1°. Single element and its 1 × 4 array have been fabricated using standard printed circuit board (PCB) process. Measured results show excellent compliance with the simulated design objectives. The antenna is low cost, low profile with simple design and is capable of being deployed in future 5G communication mobile networks.
A wide-angle scanning circularly polarized (CP) antenna array based on a novel polarizer is proposed. The working mechanism is that the linear polarization (LP) substrate integrated waveguide (SIW) ...slot antenna array can be converted into CP antenna array through the proposed hybrid polarizer. Specifically, the proposed hybrid polarizer consists of a dipole array polarizer with <inline-formula> <tex-math notation="LaTeX">6\times </tex-math></inline-formula> 6 elements and a metasurface polarizer with <inline-formula> <tex-math notation="LaTeX">19\times19 </tex-math></inline-formula> elements. The metasurface polarizer can realize the LP-CP conversion of the beams with a scanning angle range (−55°, 55°) and the dipole array polarizer can realize LP-CP conversion of beams with scanning angle ranges (−60°, −40°) and (40°, 60°) through reasonable design. Based on the complementary characteristics of the metasurface polarizer and dipole array polarizer for different scanning angles, the proposed hybrid polarizer gives the designed CP antenna array have good AR characteristics in the scanning angle range (−70°, 70°). Then, a <inline-formula> <tex-math notation="LaTeX">6\times </tex-math></inline-formula> 6 Butler matrix is designed to feed the proposed wide-angle scanning CP antenna array. Finally, a prototype of the wide-angle scanning CP antenna array is fabricated. The test results show that the AR of the proposed wide-angle scanning CP antenna array is less than 3 dB, the maximum scanning angle is −60°, and the maximum gain is more than 16.5 dBi in the operating frequency range 27.9-28.4 GHz.
In this communication, a beam-space semidefinite relaxation (BS-SDR) method is presented for synthesizing shaped power patterns of arbitrary antenna arrays. Different from the original semidefinite ...relaxation (SDR) method which optimizes all the element excitations directly, the proposed BS-SDR method constructs several analytical pencil beams whose directions cover the desired mainlobe region as well as the notch area, and the excitations for each beam basis are analytically obtained by solving the maximum Rayleigh quotient problem. Then, the proposed method optimizes only a few beam coefficients in the SDR frame to approximate the desired power pattern characteristics. In this way, the number of optimization variables can be significantly reduced, thus remarkably improving the time efficiency of the SDR-based shaped pattern synthesis. Several examples of synthesizing different shaped patterns for linear and conformal antenna arrays are provided to validate the effectiveness and advantages of the proposed method.
This article presents a novel, low-cost, beam-switchable $2 \times 10$2×10 antenna array system operating at 60 GHz. This antenna system is constructed of two rows of Chebyshev-tapered microstrip ...antenna arrays. Each row is a 10 element series-fed array which are fed by a $90^ \circ $90∘ coupler. The designed antenna array has only two input ports, but it is capable of generating three switchable beams. This antenna system can spatially scan $90^ \circ $90∘ with at least −5 dB normalised gain using only one SPDT switch and a single transceiver. The maximum gain realised by the system was measured as 16.4 dBi and the bandwidth (BW) was >1 GHz. The features of the proposed antenna system make it applicable to do mmWave research such as beamforming algorithms and channel sounding, and to use in handsets for 5G communication.
This article presents a deterministic hybrid algorithm combining the merits of Bayesian compressive sensing (BCS) and array dilation technique (ADT) for the synthesis of aperiodic and isophoric ...(equally fed) linear sparse array antennas (LSAAs). The hybrid technique overcomes the shortcomings of BCS, i.e., nonuniform amplitude taper which results into a lower taper efficiency, using hybridization with ADT resulting into an isophoric LSAA, thereby improving the taper efficiency. The proposed algorithm can be used to synthesize arbitrary antenna array patterns as per the reference pattern while complementing the constraints on the aperture length and the desired thinning levels. The hybrid algorithm provides a computationally efficient and deterministic technique for synthesizing LSAAs with low sidelobe level (SLL) and demonstrates a wide angular scanning with minimal loss in directivity and SLL over the scan volume. The results demonstrated are comparable or better than the prior literature on LSAAs.
Extremely large antenna array (ELAA) is regarded as one of the most crucial technologies for the next-generation communications due to its ability to significantly improve spectral efficiency. ...However, larger antenna aperture and higher frequency make the Rayleigh distances dramatically increased, resulting in more and more communications taking place in the near-field region. Different from traditional far-field communications, near-field communications are widely considered to be spherical wavefront-based rather than planar wavefront based, thus techniques designed for far-field scenarios might be no longer applicable. In this paper, we study the near-field communication system with an extremely large cylindrical antenna array (CLA). Under such a setup, we study the near-field beamforming, exploiting the geometrical relationship between CLA and user with the spherical-wavefront model. Specifically, we analyze the beamforming gain in the elevation angle, azimuth angle domain and distance domains, respectively. We then study the beam focusing properties in near-field CLA systems, namely the asymptotic orthogonality and the depth of focused beams. Moreover, a three-dimensional (3-D) near-field CLA codebook is proposed to make beam focusing more effective. Simulation results demonstrate that the proposed near-field codebook can effectively focus the beam to a certain location and thus improve the system achievable rate.
Robust Non-uniform LoS MIMO Array Design Palaiologos, Michail; Castaneda Garcia, Mario H.; Kakkavas, Anastasios ...
IEEE transactions on wireless communications,
2024
Journal Article
Recenzirano
The array design of multiple-input multiple-output (MIMO) systems in a line-of-sight (LoS) environment is investigated. Properly designed uniform array configurations at the transmitter (Tx) and ...receiver (Rx) can extract maximum spatial multiplexing gain only for a fixed transmit distance between the Tx and Rx arrays and for a fixed orientation of the arrays. However, such designs suffer from significant capacity variations when the position and/or orientation of the arrays is modified. To alleviate this, we examine robust, joint design of non-uniform Tx and Rx arrays, where the minimum capacity over a range of varying array positions and orientations is maximized. First, we show that, by leveraging convex relaxation, the joint Tx and Rx array design problem can be solved with convex optimization techniques in an iterative manner. Moreover, an alternative design method based on dynamic programming (DP) is proposed, which is shown to outperform the convex optimization approach. As the DP algorithm is quite demanding in terms of computational complexity, a modified DP-based algorithm is also proposed, where the Tx and Rx arrays are designed to have the same configuration. It is shown that the resulting non-uniform array configurations with the proposed designs outperform both uniform and non-uniform array designs of the literature in terms of the system robustness.
A novel circularly polarized (CP) aperture-coupled magneto-electric (ME) dipole antenna is proposed. The CP MEdipole antenna fed by a transverse slot etched on the broad wall of a section of ...shorted-end substrate integrated waveguide (SIW) is convenient to integrate into substrates. An impedance bandwidth of wider than 28.8%, a wide 3-dB axial ratio (AR) bandwidth of 25.9%, and gain of 7.7 ± 1.4 dBic over the operating band are achieved. Additionally, since the CP radiation is generated by the combination of two orthogonal ME-dipole modes, the antenna element has stable unidirectional radiation patterns that are almost identical in two principle planes throughout the operating band, which is desirable to array applications. By employing the proposed CP ME-dipole as radiating elements, an 8 x 8 high-gain wideband planar antenna array is proposed for 60-GHz millimeter-wave applications. A fabrication procedure of using conductive adhesive films to bond all print circuit board (PCB) layers together is successfully implemented to realize the array design with a three-layered geometry, which has advantages of low costs and possibility of large-scale manufacture. The measured impedance bandwidth of the fabricated prototype is 18.2% for |S 11 | <; -10 dB. Because of the wide AR bandwidth of the new antenna element, a wide AR bandwidth of 16.5% can be achieved by this array without the use of sequential feed. Gain up to 26.1 dBic and good radiation efficiency of around 70% are also obtained due to the use of a full-corporate SIW feed network with low insertion loss at millimeter-wave frequencies.
This study presents a cavity-backed aperture-coupled switch beam antenna array for 60-GHz applications. A 1 × 4-element cavity-backed aperture-coupled patch antenna array is adopted as the radiating ...part, which is fed by the Butler matrix feed network that consists of couplers, crossovers, and phase shifters. By using the cavity that can help suppress the surface wave propagation along the substrate, the array not only achieves a high-aperture efficiency and gain but also maintains a wide beam steering angle in the H-plane. The feed network is designed by using substrate integrated waveguide (SIW) technology with a low profile, low radiation loss, and low cost. Measured results show the array exhibits wide −10-dB impedance bandwidths of 12.6% (56.6–64.2 GHz) for port 1 and port 4 and 11.6% (56.8–63.8 GHz) for port 2 and port 3. The beam angle coverage is from −38° to 38° with good steerable radiation patterns.
The shared aperture antenna is regarded as one of the promising approaches to support new frequencies with very efficient space utilization. To the best of the authors' knowledge, there are few ...shared aperture antennas that include both the sub-6 GHz antenna and the millimeter-wave (mm-wave) beam-steering array for broadside applications. In this article, a broadside sharing aperture technique is developed so that a 2 <inline-formula> <tex-math notation="LaTeX">\times4\,\,26 </tex-math></inline-formula> GHz beam-steering substrate-integrated DRA (SIDRA) array can be integrated into a 3.5 GHz bandwidth enhanced perforated patch antenna in a coplanar and aperture-shared way. The proposed solution benefits from several aspects. First, the 3.5 GHz antenna features a compact size as this part is built on the substrate (where the mm-wave SIDRA is constructed) with a high permittivity. Second, the mm-wave SIDRA is a 3-D-type device, and in the case of coplanar integration, its height can be freely adapted to the thickness of 3.5 GHz antenna without concerning the impact from surface waves as many 2-D-type antennas have to do. Third, the antenna can be implemented with the multi-layer printed circuit board (PCB) process, yielding a high integrity level. The dual-frequency antenna was designed, fabricated, and measured. The performances of the antenna are reported with reasonable agreement between the measured and simulated results observed.
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