221. |
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222. |
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223. |
- Nordebo, Sven, et al.
(författare)
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Multichannel broadband Fano theory for arbitrary lossless antennas with applications in DOA estimation
- 2005
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Ingår i: Proceedings IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '05). - 1520-6149. - 0780388747 ; 4, s. 969-972
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider fundamental limitations for DOA estimation with arbitrary lossless antennas or antenna arrays inserted inside a sphere. Spherical vector modes and their associated equivalent circuits and Q factor approximations are employed as a general framework for the analysis. The classical broadband matching theory by Fano is extended to a general multiport S-parameter model of the antennas and fundamental bounds are given for the scattering parameters with respect to bandwidth and electrical size of the sphere. Finally, assuming a statistical signal model with Gaussian receiver noise, the Cramer-Rao lower bound is used to derive fundamental upper bounds for the performance of DOA estimation by a sphere.
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224. |
- Nordebo, Sven, et al.
(författare)
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Multichannel Broadband Fano Theory with Applications in Array Signal Processing
- 2005
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 0735402353 ; 750, s. 288-297
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Konferensbidrag (refereegranskat)abstract
- In this paper we consider fundamental limitations for DOA estimation with arbitrary lossless antennas or antenna arrays inserted inside a sphere. Spherical vector modes and their associated equivalent circuits and Q factor approximations are employed as a general framework for the analysis. The classical broadband matching theory by Fano is extended to a general multiport S-parameter model of the antennas and fundamental bounds are given for the scattering parameters with respect to bandwidth and electrical size of the sphere. Finally, assuming a statistical signal model with Gaussian receiver noise, the Cramer Rao lower bound is used to derive fundamental lower bounds for the performance of DOA estimation by a sphere.
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225. |
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226. |
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227. |
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228. |
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229. |
- Nordebo, Sven, et al.
(författare)
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On the Capacity of the Free Space Antenna Channel
- 2006
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Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1424401232 ; , s. 3105-3108
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the fundamental free-space antenna translation channel as an important step in understanding and developing the spherical waves as a generic tool for MIMO channel modeling. The model is demonstrated by quantifying the theoretical MIMO capacity associated with antennas exciting high order modes in the Fresnel and Fraunhofer regions.
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230. |
- Nordebo, Sven, et al.
(författare)
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On the Design of Optimal Measurements for Antenna Near-Field Imaging Problems
- 2006
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Ingår i: AIP Conference Proceedings. - : AIP. ; 834, s. 234-249
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Konferensbidrag (refereegranskat)abstract
- A mathematical framework is introduced for optimization of antenna near-field imaging problems, based on the multipole expansion of the electromagnetic field, the Fisher information to quantify the quality of data and use of modern interior point convex optimization techniques. We consider the general problem of optimizing the measurement sensor allocation for parameter estimation in distributed systems, and in particular the problem of optimizing the measurement set-up for antenna near-field estimation. As an application example for antenna near-field imaging, we consider a relevant measurement set-up using cylindrical probing coordinates. The convex optimization problem is examined using duality theory, and it is shown that several structural properties of the optimal measurement problem can be exploited in developing an efficient interior point optimization method. In particular, we show that the cylindrical measurement set-up yields a Fisher information matrix with block diagonal structure, a feature which can be directly exploited in the optimization algorithm by reducing the number of dual decision variables.
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