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- Ghadimi, P., et al.
(författare)
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Dynamic response of a wedge through asymmetric free fall in 2 degrees of freedom
- 2019
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 2041-3084 .- 1475-0902. ; 233:1, s. 229-250
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Tidskriftsartikel (refereegranskat)abstract
- In this article, a mathematical model is presented for simulation of the coupled roll and heave motions of the asymmetric impact of a two-dimensional wedge body. This model is developed based on the added mass theory and momentum variation. To this end, new formulations are introduced which are related to the added mass caused by heave and roll motions of the wedge. These relations are developed by including the asymmetrical effects and roll speed. In addition, by considering the roll speed, a particular method is presented for the time derivative of half-wetted beam of an asymmetric wedge. Furthermore, two equations are derived for the roll and heave motions in which damping terms appear. Validity of the proposed method is verified by comparing the predicted results against available experimental data in two conditions of roll motion and no roll motion. Favorable agreement is observed between the predicted results and experimental data. The pressure and hydrodynamic load are computed, and the differences between the results associated with the considered conditions are explored. Subsequently, the effects of different physical parameters including deadrise angle, initial roll angle, and initial velocity on the dynamic response of a two-dimensional wedge section are investigated. Ultimately, time histories of hydrodynamic coefficients are determined in order to provide a better understanding of the derived equations. 017.
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2. |
- Anjos, Eduardo V.P., et al.
(författare)
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FORMAT: A Reconfigurable Tile-Based Antenna Array System for 5G and 6G Millimeter-Wave Testbeds
- 2022
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Ingår i: IEEE Systems Journal. - 1932-8184 .- 1937-9234. ; 16:3, s. 4489-4500
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Tidskriftsartikel (refereegranskat)abstract
- This article introduces the FORMAT array, a reconfigurable millimeter-wave antenna array platform based on antenna tiles. FORMAT stands for Flexible Organization and Reconfiguration of Millimeter-wave Antenna Tiles, which is a unique hardware solution aiming to implement and demonstrate a variety of antenna array concepts, as well as different array architectures and configurations from the same basic module, providing even benchmark between different solutions and thus valuable insights into fifth-generation (5G) and beyond-5G antenna systems. The combination of a minimum-sized tile with 3D-printed frame parts enables antenna arrays of a variety of sizes, allows multiple beamforming architectures, and a range of different antenna element positioning in the array. The hardware implementation is thoroughly described, with a few different array assemblies being manufactured and measured, validating their antenna performance with over-the-air measurements. Finally, using FORMAT hardware as both base station and user equipment, a 5-m wireless communication link was set up, achieving 4.8 Gbps downlink speed with QAM64 modulation.
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3. |
- Fager, Christian, 1974, et al.
(författare)
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IC Design Aspects for 5G mm-Wave Systems
- 2020
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Ingår i: 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC). - 2325-0305. - 9782874870590 ; , s. 870-871
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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4. |
- Haddadi, Abolfazl, et al.
(författare)
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Low-profile planar eleven antenna over a magnetic plane
- 2016
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Ingår i: 2016 10th European Conference on Antennas and Propagation, EuCAP 2016. - 9788890701863 ; , s. Art. no. 7481553-
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Konferensbidrag (refereegranskat)abstract
- The eleven antenna has been greatly used in many applications to achieve low reflection coefficient and stable-pattern over ultra-wide-bands. However, arraying in the eleven configuration forces the antenna designer to tilt the antenna over an electric conducting ground plane, and this makes it mechanically complicated and increases the profile of the antenna. Seeking new capabilities, the theory of putting log-periodic dipoles in the eleven configuration over magnetic ground is developed. The eleven antenna is formed by two printed folded-dipoles, and we evaluate the performance for a single-pair of dipoles and five-pairs of dipoles. The results are extracted for the cases of PEC ground, PMC ground and without ground. The results are in a good agreement with theory. Also, some discussions are provided for the realization of the artificial-magnetic-ground.
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5. |
- Taghikhani, P., et al.
(författare)
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High gain V-band planar array antenna using half-height pin gap waveguide
- 2017
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Ingår i: 2017 11th European Conference on Antennas and Propagation, EUCAP 2017. - 2164-3342. ; , s. 2758-2761
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Konferensbidrag (refereegranskat)abstract
- With growing demand for mm-Wave applications, gap waveguide technology introduced many advantageous features compared to hollow waveguides or SIW. Till now several wideband, high-efficiency and highly directive planar gap waveguide antennas have been proposed. Recently, a new form of pins, the so called half-height pin, is proposed for realizing gap waveguide technology. In this paper, a wide-band, high gain, and high efficiency 8×8-element slot array antenna for 60 GHz band based on the new form of pins is introduced. The simulation shows a very good performance of the antenna, with 14% bandwidth of the 10 dB return loss, 26 dBi realized gain and close to 80% aperture efficiency. The antenna has less difficulty in manufacturing because of new pin form and therefore is suitable for the low cost mass production of mm-Wave antennas.
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