| 1. |
- Alfonso, E., et al.
(författare)
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Power divider in ridge gap waveguide technology
- 2010
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Ingår i: EuCAP 2010 Fourth European Conference on Antennas and Propagation, Barcelona, 12-16 April 2010. - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- A power divider in ridge gap waveguide technology has been designed to work at 15GHz. Measurements and simulations are provided. Besides, a broad numerical study of the characteristic impedance of a ridge gap waveguide is presented.
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| 2. |
- Bosiljevac, M., et al.
(författare)
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Efficient spectral domain Green's function analysis of novel metamaterial bandgap guiding structures
- 2010
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Ingår i: EuCAP 2010 Fourth European Conference on Antennas and Propagation, Barcelona, 12-16 April 2010. - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- The Green's function analysis of oversized waveguides with one wall realized as a periodic structure is presented in this paper. Two different realizations of the periodic structures were considered: the bed-of-nails surface and the mushroom surface. Since the period of these surfaces is small compared to wavelength it is possible to take advantage of the asymptotic boundary conditions in the derivation of the required Green's functions. By doing so, we avoid the usual Floquet mode approach needed in the analysis of periodic surfaces and significantly reduce the overall numerical complexity. The Green's functions developed in this way allow dispersion and electromagnetic field analysis since their poles correspond to surface wave modes and waveguide modes. These results reveal the dispersion characteristics of the observed structures and the bandwidth usable in the waveguide applications. The computed results are compared with the results obtained with a general electromagnetic solver and the agreement is very good.
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| 3. |
- Ellgardt, Anders, et al.
(författare)
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Edge element evaluation of tapered-slot elements in phased arrays
- 2010
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Ingår i: EuCAP 2010 - The 4th European Conference on Antennas and Propagation. - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- The edge elements in large phased arrays of tapered-slot elements are analyzed and compared with the infinite array. In large phased arrays the elements that are close to the center of the antenna have similar performance. However, the elements close to an edge will have different coupling coefficients and embedded radiation patterns due to the truncated geometry. In this paper the edge effects in a triangular grid tapered-slot array is studied by using finite-by-infinite arrays. The array is infinite in the direction along the edge and finite in the other direction. The S-parameters for three truncations of the tapered slot element are compared with the infinite array solution for the case when the edge is orthogonal to the E-plane.
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| 4. |
- Gustafson, Carl, et al.
(författare)
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Archimedean spiral antenna for underground soil measurements in Greenland
- 2010
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Ingår i: [Host publication title missing]. - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a thin single-arm Archimedean spiral antenna designed to be used in underground soil measurements to characterize the dielectric properties of soil during freezing and thawing processes. The designed antenna works in low permittivity, low-loss frozen soil as well as in high permittivity, high-loss marshy soil and operates over the frequency range 1–3 GHz. The antennas has been successfully used for measurements of soil properties in situ.
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| 5. |
- Gustafsson, Mats, et al.
(författare)
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Constraints on the temporal dispersion of metamaterials
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9781424464319 - 9788476534724 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- The frequency dependence of the permittivity, permeability, and index of refraction restrict metamaterial applications such as cloaking and perfect lenses. Here, the principles of causality and passivity together with identities for Herglotz functions are used to construct various sum rules. The sum rules relate the frequency dependence of the material parameters with their high- and low-frequency values. The corresponding physical bounds determine minimum variations of the material parameters over a frequency interval.
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| 6. |
- Haneda, Katsuyuki, et al.
(författare)
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Measurement of loop-back interference channels for outdoor-to-Indoor full-duplex radio relays
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9788476534724 - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- A full-duplex relay enhances the end-to-end spectral efficiency compared to a half-duplex relay, provided that the loop-back interference at relays is managed well. In order to study the feasibility of the full-duplex relay, it is crucial to measure and model the loop-back interference channels. This paper presents a measurement campaign of these channels for outdoor-to-indoor communications. A compact relay antenna was developed to serve as a signal repeater between outdoor base stations and indoor users, and was used for the loop-back interference channel measurement. Measurement results revealed that the mean interference level was -48 dB in the compact relay antenna, and it could be further reduced by placing the outdoor and indoor antennas in a different position referred to as a separate relay. Combined with an appropriate countermeasure to reduce the interference level, such as an interference canceller, the full-duplex operation of indoor compact relay terminal was found to be feasible.
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| 7. |
- Hult, Tommy, et al.
(författare)
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Analytical dual-link MIMO channel model using correlated correlation matrices
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9788476534724 - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- Analytical Multiple-Input Multiple-Output (MIMO) models are often attractive due to their low complexity when analyzing possibilities and limitations in the system. In this paper we outline a a possible dual link extension of an analytical MIMO channel model and investigate its suitability based on measurements of a dual link MIMO scenario. The extension is based on the correlation matrix distance (CMD) as a gauge to generate correlation matrices for the additional links of the multi-link scenario.
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| 8. |
- Jamaly, Nima, 1979, et al.
(författare)
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Performance of directive multi-element antennas versus multi-beam arrays in MIMO communication systems
- 2010
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Ingår i: EuCAP 2010 Fourth European Conference on Antennas and Propagation, Barcelona, 12-16 April 2010. - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- In an isotropic rich scattering environment, the shape of the patterns of the elements has long been considered as irrelevant to their Multiple-Input and Multiple-Output (MIMO) performances. In the current communication it is cleared that the directivities of the embedded elements, which are immediate outcomes of their patterns, contribute to the diversity gains as well as capacity of the system. Indeed, the number of scatterers plays a significant role in this respect. It is demonstrated that unless the number of scatterers is high enough, the diversity gain and capacity do not reach their final limits, even though the spatial correlation and radiation efficiencies reside on their ideally best levels. A brief study of the matter is presented in this paper and the simulation results are verified by measurements in reverberation chamber.
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| 9. |
- Javashvili, Otar, et al.
(författare)
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New method for design implementation of Vivaldi antennas to improve its UWB behaviour (EuCAP 2010)
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9781424464319 - 9788476534724
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Konferensbidrag (refereegranskat)abstract
- The aim of this paper is to investigate the parameters of one of the UWB Sensors, called Vivaldi Antenna, and to propose the new ways how they can be improved. As a practical implementation of the sensor, the UWB radar for wall penetrating applications with impulse excitation was utilized. For wall penetration low frequency (0.3 – 8 GHz) supporting UWB signals are required. Within the scope of this project, the Vivaldi antenna parameters are improved in order to optimize the radiation bandwidth with an usable gain response along the whole operating band, including lower frequencies. It also automatically leads to the optimization of the size of the antenna. In addition, an investigation of the phase linearity and UWB behavior of the antenna was carried out.
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| 10. |
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