| 31. |
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| 32. |
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| 33. |
- Ericsson, Andreas, et al.
(författare)
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Experimental Characterization of Circular Polarization Selective Structures Using Linearly Single-Polarized Antennas
- 2017
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 65:8, s. 4239-4249
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: We present a technique for performing high-accuracy measurements of the transmission and reflection properties in circular polarizations (CPs) of a test panel. Using linearly polarized antennas and measuring at four different antenna orientations, all with a relative rotation of 45°, an efficient normalization of each scattering component can be utilized. This method achieves a high signal-to-noise ratio in all normalized linear polarization components used to synthesize the CP scattering. Furthermore, a postprocessing scheme is introduced to compensate for measurement uncertainties due to antenna misalignments. The novel measurement and postprocessing techniques are utilized to characterize a manufactured wideband CP selective structure, both in transmission and reflection, and the measurement results are in excellent agreement with simulation results from commercial software. The repeatability of the measurement results is investigated, and the results are in the expected range in comparison with estimated measurement uncertainties.
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| 34. |
- Ericsson, Andreas, et al.
(författare)
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Functional Structures Applied to Doubly Curved Surfaces
- 2016
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Konferensbidrag (refereegranskat)abstract
- The effect of curvature on the performance of electromagnetic functional structures, such as electromagnetic absorbers and frequency selective surfaces, is investigated in this work. The monostatic radar cross section of a doubly curved, rotationally symmetric scatterer, with and without a coating electromagnetic absorber, is calculated. An analytical expression for calculating the far-field from the electric and magnetic fields of a single azimuthal mode excitation in circular polarization has been derived, in order to achieve fast and efficient full wave simulations. It is concluded that the effect of curvature is more severe for absorbers based on resistive sheets that for absorbers based on bulk loss.
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| 35. |
- Ericsson, Andreas, et al.
(författare)
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Scattering for doubly curved functional surfaces and corresponding planar designs
- 2016
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Ingår i: 10th European Conference on Antennas and Propagation (EuCAP), 2016. - 9788890701863
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Konferensbidrag (refereegranskat)abstract
- We present a study of the performance degradation of electromagnetic absorbers when applied to doubly curved surfaces. The scattering from a perfectly conducting sphere coated with different types of single- and multilayer absorbers has been evaluated using analytic recursion expressions. A comparison of the effect of curvature on the absorber performance is presented for structures based on homogeneous resistive sheets and low permittivity spacers, circuit analog absorbers, bulk material absorbers, and ultra thin magnetic absorbers. A conclusion from this study is that bulk absorbers, based on lossy materials, are less sensitive to curvature than absorbers consisting of multiple layers of low permittivity spacers and resistive sheets.
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| 36. |
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| 37. |
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| 38. |
- Eriksson, Carl, 1981-, et al.
(författare)
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Long-term effectiveness of vedolizumab in inflammatory bowel disease : a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG)
- 2017
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Ingår i: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 52:6-7, s. 722-729
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Clinical trials have demonstrated the efficacy of vedolizumab in inflammatory bowel disease (IBD). However, these findings may not reflect the clinical practice. Therefore, we aimed to describe a vedolizumab-treated patient population and assess long-term effectiveness.Materials and methods: Patients initiating vedolizumab between 1 June 2014 and 30 May 2015 were identified through the Swedish National Quality Registry for IBD. Prospectively collected data on treatment and disease activity were extracted. Clinical remission was defined as Patient Harvey Bradshaw index<5 in Crohn's disease (CD) and Patient Simple Clinical Colitis Activity index<3 in ulcerative colitis (UC).Results: Two-hundred forty-six patients (147CD, 92 UC and 7 IBD-Unclassified) were included. On study entry, 86% had failed TNF-antagonist and 48% of the CD patients had undergone1 surgical resection. After a median follow-up of 17 (IQR: 14-20) months, 142 (58%) patients remained on vedolizumab. In total, 54% of the CD- and 64% of the UC patients were in clinical remission at the end of follow-up, with the clinical activity decreasing (p<.0001 in both groups). Faecal-calprotectin decreased in CD (p<.0001) and in UC (p=.001), whereas CRP decreased in CD (p=.002) but not in UC (p=.11). Previous anti-TNF exposure (adjusted HR: 4.03; 95% CI: 0.96-16.75) and elevated CRP at baseline (adjusted HR: 2.22; 95% CI: 1.10-4.35) seemed to be associated with discontinuation because of lack of response. Female sex was associated with termination because of intolerance (adjusted HR: 2.75; 95% CI: 1.16-6.48).Conclusion: Vedolizumab-treated patients represent a treatment-refractory group. A long-term effect can be achieved, even beyond 1 year of treatment.
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| 39. |
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| 40. |
- Gustafsson, Mats, et al.
(författare)
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An overview of some recent physical bounds in scattering and antenna theory
- 2009
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Ingår i: ; , s. 1715-1718
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Konferensbidrag (refereegranskat)abstract
- The objective of this paper is to give an overview of some recently developed sum rules and physical bounds in scattering and antenna theory. The sum rules are based on integral identities for Herglotz functions that relate the quantity of interest with its low and high-frequency behavior. The sum rules are transformed to bounds by estimating the integrals and applying variational results to the parameters that appear in the asymptotic expansions. The theoretical findings are exemplified by numerical results for various scattering and antenna configurations.
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