| 1. |
- Bencivenni, Carlo, 1986, et al.
(författare)
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Aperiodic Switched Array for Line-of-Sight MIMO Backhauling
- 2018
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 17:9, s. 1712-1716
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Tidskriftsartikel (refereegranskat)abstract
- A switchable aperiodic array solution is proposed to increase the minimum channel capacity of a multiple-input-multiple-output (MIMO) backhauling system over an extended line-of-sight communication range. The objective is to propose a low-complexity design solution that is cost-effective in regard to the manufacturing, installation, and its design process. It is shown that by adding only one switch and one auxiliary antenna per base station, a 4 × 4 MIMO system can be realized that is capable of minimizing the capacity loss that both regular and aperiodic arrays suffer from as a function of the link distance.
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| 2. |
- Bencivenni, Carlo, 1986, et al.
(författare)
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Design of Maximally Sparse Antenna Arrays in the Presence of Mutual Coupling
- 2015
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1548-5757 .- 1536-1225. ; 14, s. 159-162
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Tidskriftsartikel (refereegranskat)abstract
- An optimization framework is proposed that combines electromagnetic field simulations with an iterative l(1)-norm minimization procedure to synthesize optimally sparse antenna arrays. The proposed approach overcomes the limitation of design methodologies that assume idealized antenna elements employing equal (isolated or isotropic) element patterns, as these yield suboptimal solutions when the antenna mutual coupling effects cannot be ignored. The latter is demonstrated for arrays of relatively strongly coupled dipole radiators.
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| 3. |
- Du, Yijun, et al.
(författare)
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Design of Sharp Roll-Off Band Notch with Fragment-Type Pattern Etched on UWB Antenna
- 2018
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225 .- 1548-5757. ; 17:12, s. 2404-2408
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Tidskriftsartikel (refereegranskat)abstract
- Fragment-type etch patterns are proposed and designed on ultra-wideband planar antenna to acquire sharp roll-off band notch. Multi-objective evolutionary algorithm is applied to achieve the optimization searching of the best fragment-type etch pattern by setting multiple objectives to acquire the exact notched band and challenge the roll-off criterion (ROC) of band notch. Efficiency of the design can be improved by properly presetting slits on the patch radiator. For demonstration, designs with different slit presetting are implemented and tested. With single slit preset, band notch of ROC=0.72 at the WLAN band ranging from 5.15 GHz to 5.85GHz is acquired.
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| 4. |
- Ebrahimpouri, Mahsa, et al.
(författare)
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Ultrawideband Anisotropic Glide-Symmetric Metasurfaces
- 2019
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1536-1225 .- 1548-5757. ; 18:8, s. 1547-1551
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents a method to realize anisotropic two-dimensional designs with wideband operation. Glide symmetry has been proven to increase the bandwidth and equivalent refractive index of periodic structures. Here, two anisotropic glide-symmetric unit cells are proposed and characterized. Our simulated results prove that these unit cells follow the general behavior of periodic structures possessing glide symmetry. Moreover, we demonstrate that higher level of anisotropy can also be achieved by glide symmetry. Combining our proposed anisotropic glide-symmetric unit cell and transformation optics, a 30% compressed Luneburg lens is designed. The lens operates from 1 to 13 GHz.
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| 5. |
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| 6. |
- Frid, Henrik
(författare)
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Closed-Form Relation between the Scan Angle and Feed Position for Extended Hemispherical Lenses based on Ray-Tracing
- 2016
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - : IEEE Press. - 1536-1225 .- 1548-5757. ; 15, s. 1963-1966
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents a closed-form relation between the scan angle and feed position for extended hemispherical lenses. This relation is derived using ray tracing, and it is valid for both large and small scan angles, in excellent agreement with full-wave simulations. It is demonstrated that the relation is linear in the small-angle limit, and the effective focal length determining the scan angle is presented. It is also demonstrated that the scan angle only depends on the geometrical configuration, and that it is independent of the lens material. To demonstrate the applicability of this scan angle relation to the design of focal plane arrays (FPAs), we demonstrate that it can be used to determine the FPA spacing that results in -3-dB overlap between switched beams. A comparison with full-wave simulations of lenses with varying materials and FPA elements demonstrates a root-mean-square (rms) accuracy of 0.27 degrees for the scan angle estimation, and rms accuracy of 0.26 dB for the -3-dB overlap criterion between the central and adjacent beams. Finally, we present scaling rules, which show that the scan resolution is inversely proportional to the lens diameter, whereas the FPA spacing is independent of the total lens size.
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| 7. |
- Helander, Jakob, et al.
(författare)
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Performance Analysis of Millimeter-Wave Phased Array Antennas in Cellular Handsets
- 2016
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225 .- 1548-5757. ; 15, s. 504-507
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Tidskriftsartikel (refereegranskat)abstract
- This letter discusses the usage of high-gain steerable antenna arrays operating at millimeter-wave (mmWave) frequencies for future cellular networks (5G). Based on the probable outline of the 5G networks, a method for characterizing phased array antennas in cellular handsets has been introduced. For analyzing the performance, the total scan pattern of the array configuration together with its respective coverage efficiency are essential to consider in order to compare different antenna designs and topology approaches with each other. Two design approaches and subarray schemes of these have been considered in order to illustrate the relevance of such a characterization method. The results show the importance of evaluating potential array antennas in such manners. The method can be applied to much more complex system models, where polarization diversity, hand and body effect, and statistical modeling of the channel may be included.
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| 8. |
- Hong, Wonbin, et al.
(författare)
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Guest Editorial Antenna-in-Package, Antenna-on-Chip, Antenna-IC Interface: Joint Design and Cointegration
- 2019
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 18:11, s. 2345-2350
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The twenty peer-reviewed letters in this special section examine the design and cointegration of antenna-in-package (AiP), antenna-on-chip (AoC), and antenna ICs (AIC). The letters are categorized in the four distinctive categories: 1) Fabrication technologies (four); 2) Measurement strategies; 3) Applications; and 4) New design and integration strategies. Fruition of major thrusts such as 5G/6G, high-resolution radar and imaging, autonomous driving, and space technology are highly intertwined with the advance of applied electromagnetics. Miniaturization and seamless integration of microwave components and radio systems can enable superior performance, form factor, and cost efficiencies leading to enhanced proliferation of such applications. Historically, radio frequency front ends, antennas, and microwave components have separately evolved using distinct fabrication and measurement technologies.
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| 9. |
- Iupikov, Oleg, 1983, et al.
(författare)
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Domain-Decomposition Approach to Krylov Subspace Iteration
- 2016
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1548-5757 .- 1536-1225. ; 15, s. 1414-1417
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Tidskriftsartikel (refereegranskat)abstract
- Krylov subspace iterative techniques consist of finding the solution of a scattering problem as a linear combination of "generating vectors" obtained through successive matrix-vector multiplications. This letter extends this approach to domain-decomposition. Here, on each subdomain, a subspace is obtained by constructing the segments of each generating vector associated with the subdomain and by weighting these segments independently, which provides more degrees of freedom. The method is tested for scattering by a sphere and a rectangular plate, as well as radiation from connected arrays with strongly coupled antenna elements. It is shown that substantial computational savings can be obtained for the sphere and the array. This opens up new perspectives for faster solutions of multiscaled problems.
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| 10. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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Fundamental Directivity Limitations of Dense Array Antennas: A Numerical Study Using Hannan´s Embedded Element Efficiency
- 2016
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 15, s. 766-769
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Tidskriftsartikel (refereegranskat)abstract
- Hannan introduced in 1964 an embedded element efficiency concept that explains the so-called element-gain paradox in antenna arrays, i.e. that the array gain always is smaller than the sum of the element gains. In the present paper we show for the first time the usefulness of his approach by evaluating directivities and aperture efficiencies of an array of open-ended waveguides by commercial full-wave EM solvers for a large range of element spacing. The results show also that by using embedded element analysis, the realized gain of regular arrays actually becomes equal to the sum of the realized gains of the embedded elements. Thus, the embedded element efficiency ismore practical to use in design and numerical analysis than the more commonly used active element pattern approach. We also show that the embedded element efficiency can be approximatedby a simple formula when the element spacing is smaller than half wavelength.
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