| 1. |
- Algaba Brazalez, Astrid, 1983, et al.
(författare)
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Investigation of Transitions for Use in Inverted Microstrip Gap Waveguide Antenna Arrays
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 9788890701849 ; , s. 995 - 999
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Konferensbidrag (refereegranskat)abstract
- The main purpose of this work is to create good transitions for inverted microstrip-based versions of gap waveguide that are used to feed slot or horn antenna arrays. Two new millimeter-wave transitions from inverted microstrip gap waveguide to rectangular waveguide are presented. Both geometries are similar and consist of a planar probe, which contains a rectangular patch or T-section. The planar probe is inserted inside the rectangular waveguide through an opening made in the broadside wall of the waveguide. The main difference between the two geometries is that one of them extends upwards and the other one downwards with respect to the planar inverted microstrip gap waveguide circuit. The simulated S-parameters show promising results.
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| 2. |
- Beckman, C., et al.
(författare)
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Design Considerations for the EISCAT_3D Phased Array Antenna
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - Piscataway, NJ : IEEE. - 9788890701849 ; , s. 1700-1704
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Konferensbidrag (refereegranskat)abstract
- This paper presents a background and an overview of the initial design considerations for phased array antenna being designed for the New Generation multi-static, incoherent-scatter radar station - EISCAT-3D - in Northern Scandinavia. Its anticipated electrical, mechanical and environmental design requirements are given both by the physics as well as by the extreme climate in the subarctic region of northern Scandinavia.
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| 3. |
- Beukman, Theunis S., 1986, et al.
(författare)
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A Quadraxial Feed for Ultra-Wide Bandwidth Quadruple-Ridged Flared Horn Antennas
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 3312 - 3316
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Konferensbidrag (refereegranskat)abstract
- A quadraxial feed, excited by two orthogonal differential modes, is proposed for ultra wideband quadruple-ridged flared horn (QRFH) antennas that obviates the need for a balun. It is shown that in this configuration the fundamental TE11 mode is most strongly excited over the entire frequency band, while the higher-order modes are significantly suppressed, as compared to the conventional excitation using the ridge-to-coax balun transition. These properties lead to several advantages for QRFH antenna applications which require frequency-invariant beam characteristics, high port isolation and low cross-polarisation level, such as e.g. reflector antenna feeds for future radio telescopes.
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| 4. |
- Cappellin, C., et al.
(författare)
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Novel multi-beam radiometers for accurate ocean surveillance
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 9788890701849 ; , s. 3531-3535
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Konferensbidrag (refereegranskat)abstract
- Novel antenna architectures for real aperture multi-beam radiometers providing high resolution and high sensitivity for accurate sea surface temperature (SST) and ocean vector wind (OVW) measurements are investigated. On the basis of the radiometer requirements set for future SST/OVW missions, conical scanners and push-broom antennas are compared. The comparison will cover reflector optics and focal plane array configuration.
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| 5. |
- Condo Neira, Edith, 1979, et al.
(författare)
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Evaluation of V2X Antenna Performance Using a Multipath Simulation Tool
- 2014
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Ingår i: Antennas and Propagation (EuCAP), Proceedings of the 8th European Conference, The Hague, The Netherlands, Apr. 2014. - 9788890701849 ; , s. 2534-+, s. 2534-2538
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Konferensbidrag (refereegranskat)abstract
- Antennas are one of the key components for efficient and reliable vehicular communications systems; especially for safety related applications the antenna performance is crucial. It is therefore important to be able to evaluate the antenna performance under realistic conditions so that the best antenna solution can be selected. In this paper we present a statistical method for evaluating the antenna performance by using the antennas radiation patterns and a multipath simulation tool. The multipath environment is generated by a number of incident waves with a specific angle of arrival distribution, defined by the user. In order to generate voltage samples at the antenna ports many sets of incident waves are generated. This simulates a changing environment as, e.g., when the vehicle is moving. By studying the cumulative distribution functions (CDFs) for the voltage samples we are able to compare the performance for different antenna types, positions on the vehicle, etc. The method is fast and effective and, when applied to typical vehicular propagation environments, the importance of having antennas with radiation patterns capable of covering the whole azimuth plane is demonstrated.
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| 6. |
- Dobsicek Trefna, Hana, 1979, et al.
(författare)
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Antenna Applicator for Microwave Hyperthermia Treatment of Pediatric Brain Cancer
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 9788890701849
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is proposed. The applicator consists of up to 16 antennas placed around the head in a helmet-like set-up and operates at a frequency range of 430-1000~MHz. The self-grounded bow-tie antennas are housed in a molded plastic enclosure with the shape of a truncated cone. The inner space of the enclosure is filled with distilled water. The antennas are attached to a perimetric water bolus with a thickness of 2 cm and aligned with the head shape. The focusing ability of the applicator was investigated on a homogeneous SAM model and on a model of a 13-year old patient containing a spherical tumor of 2 cm radius. Two different tumor positions were investigated: the right frontal lobe and the central brain. The obtained SAR distributions are favorable, although a relatively high level of energy is also absorbed on the surface of the body. This heating is however not expected to cause problems as it can be cooled by blood perfusion and water bolus. Our results show that focused microwave heating in the brain is feasible and warrants further verification on phantoms.
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| 7. |
- Einarsson, Bjarni Thor, 1987, et al.
(författare)
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Measurements of relative Throughput in Reverberation Chamber using Universal Software Radio Peripheral
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 1105-1108
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Konferensbidrag (refereegranskat)abstract
- This paper aims to show how Universal Software Radio Peripheral can be used in conjunction with reverberation chamber to measure throughput of wireless communication systems in Rich Isotropic Multipath environment. The results are in agreement with theories based on the threshold receiver model.
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| 8. |
- Gustafson, Carl, et al.
(författare)
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Modeling the cluster decay in mm-wave channels
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 9788890701849 ; , s. 803-807
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Konferensbidrag (refereegranskat)abstract
- © 2014 European Association on Antennas and Propagation.The cluster power is an important parameter for cluster-based wireless channel models. This paper addresses modeling and estimation of the cluster power for wireless channels. A novel way of estimating the cluster decay and cluster fading, where the effects of the noise floor is taken into account, is presented. Due to the noise floor present in the measurement, only a limited number of clusters are available when estimating the cluster decay. It is shown that the estimated cluster decay and cluster fading can be improved if the effects of the noise floor and cluster fading are modeled and taken into account in the estimation step. If the noise floor is not taken into account in the estimation of the cluster decay, the resulting model can overestimate the RMS delay spread. Further, the paper includes estimates of the cluster decay and fading based on measured clusters for an indoor wireless mm-Wave channel in a conference room environment.
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| 9. |
- Gustafsson, M., et al.
(författare)
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OTA Characterization of mu BTS Antenna in RIMP and Random-LOS
- 2014
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Ingår i: 2014 8th European Conference on Antennas and Propagation (Eucap). Hague, NETHERLANDS. APR 06-11, 2014. - 2164-3342. - 9788890701849 ; , s. 1394-1397
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Konferensbidrag (refereegranskat)abstract
- During the past recent years, Huawei Technologies have had the ambition to strengthen the competence of the company by establishing cooperation projects with strong scientific academic centers in the world. The antenna department at Chalmers University of Technology is identified as one such important knowledge center, and a one year cooperation project was hence defined in 2012 and the project took off by October in the autumn that year. The goal of the project was to identify a compact antenna solution usable for small cell BTS solutions, which would support MIMO up to four layer spatial multiplexing. This paper is a brief summary of the methodology used for the theoretical studies done within the project, as well as a short presentation of the chosen bowtie antenna solution.
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| 10. |
- Iupikov, Oleg, 1983, et al.
(författare)
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Dense focal plane arrays for pushbroom satellite radiometers
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014; The Hague; Netherlands; 6 April 2014 through 11 April 2014. - 9788890701849 ; , s. 3536-3540
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Konferensbidrag (refereegranskat)abstract
- Performance of a dense focal plane array feeding an offset toroidal reflector antenna system is studied and discussed in the context of a potential application in multi-beam radiometers for ocean surveillance. We present a preliminary design of the array feed for the 5-m diameter antenna at X-band. This array is optimized to realize high antenna beam efficiency (∼ 95%) over a wide scan range (±20°) with very low side-lobe and cross-polarization levels.
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| 11. |
- Jamaly, Nima, 1979, et al.
(författare)
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Analysis and Measurement of Multiple Antenna Systems for Fading Channel Prediction in Moving Relays
- 2014
-
Ingår i: 2014 8TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - 2164-3342. - 9788890701849 ; , s. 2015-2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The performance of wireless data transmission to mobile vehicles is improved if channel state information is available at the transmitter but movement of vehicles causes outdating of channel estimates. The concept of a predictor antenna has recently been proposed, where an antenna is placed in front of other antennas on the roof of the vehicle to sense the radio environment in advance. This can comparatively provide an order-of-magnitude improvement in channel prediction performance. A potential problem with this idea is that closely placed antennas will experience mutual electromagnetic couplings. These may reduce the efficiency of the predictor antenna concept if they are not taken into account. In this paper, we discuss about how to treat the forgoing issue and eventually evaluate a promising candidate on measured channels. We argue that only open-circuit voltage method would be realistic for the present application. The usefulness of the proposed decoupling method is demonstrated on field measurements obtained in downtown Dresden, Germany. We also partly address the sensitivity of the open-circuit decoupling method to the accuracy of the utilized network parameters.
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| 12. |
- Jian, Qiuchi, 1984, et al.
(författare)
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Detection of breathing and heartbeat by using a simple UWB radar system
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 2164-3342. - 9788890701849 ; , s. 3078-3081
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Konferensbidrag (refereegranskat)abstract
- We present the development on an ultra-wideband (UWB) radar system and its signal processing algorithms for detecting human breathing and heartbeat in the paper. The UWB radar system consists of two (Tx and Rx) antennas and one compact CMOS UWB transceiver. Several signal processing techniques are developed for the application. The system has been tested by real measurements. .
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| 13. |
- Karlsson, Kristian, et al.
(författare)
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Utilizing two-ray interference in vehicle-to-vehicle communications
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - : Institute of Electrical and Electronics Engineers Inc.. - 9788890701849 ; , s. 2544-2547, s. 2544 - 2547
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method for the utilization of radio channels with two-ray propagation properties between vehicles in vehicle-to-vehicle communications. The method uses spatial diversity with antennas separated in the vertical direction to counteract low received levels in regions of destructive interference according to a two-ray path loss model. Results are exemplified with measurements and further analysed with simulations.
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| 14. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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Fundamental Limitations on Small Multi-Beam Antennas for MIMO Systems
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 329-331
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Konferensbidrag (refereegranskat)abstract
- The paper finds theoretical limitations with MIMO technology of higher order when space is limited. The results show that it is possible to achieve up to six independent identically distributed (i.i.d.) channels in rich isotropic multipath (RIMP) by combining different incremental sources to an incrementally small 6-port antenna. This means that we with incrementally small antennas can generate MIMO performance with maximum six data streams in RIMP (rank 6). We also show that it is possible to achieve completely isotropic full-spherical angular coverage by using an incrementally small 3-port antenna consisting of three orthogonal electric or magnetic dipoles. However, it is possible to get isotropic spatial coverage with 3 dB higher directivity in all directions by using a 6-port antenna consisting of both three orthogonal electric dipoles and three orthogonal magnetic dipoles, or alternatively a 6-port Huygens antenna consisting of 6 uncoupled Huygens sources. In random-LOS (having only a single angle of arrival) there will be a maximum of two data streams (rank 2) available, associated with two orthogonal polarizations. We show that both streams can be received with the 3-port incremental dipole antenna, and with 3 dB higher power with either of the 6-port antennas. The randomness of the angle of arrival in LOS is caused by the arbitrary orientation and location of the user-terminal.
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| 15. |
- Li, Hui, et al.
(författare)
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Analysis of SAR on flat phantom for different multi-antenna mobile terminals
- 2014
-
Ingår i: European Conference on Antennas and Propagation (EuCAP), 2014. - 2164-3342. - 9788890701849 ; , s. 1989-1989
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Konferensbidrag (refereegranskat)abstract
- Evaluation of Specific Absorption Rate (SAR) for multiple antenna systems is becoming important, with the upcoming deployment of LTE-Advanced. In this work, the influence of different antenna locations and antenna types was investigated for stand-alone SAR and simultaneous SAR, to provide some guidelines for antenna design in multi-antenna handsets. For simultaneous SAR, different phase shifts between antenna ports were considered and the averaged SAR was used as a metrics for comparison. The SAR performances were evaluated in simulation for the body worn scenario, and different placements of the mobile handset, i.e., with either the screen or back side closer to the body, were studied.
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| 16. |
- Ludick, D. J., et al.
(författare)
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A comparison of domain decomposition techniques for analysing disjoint finite antenna arrays
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 2164-3342. - 9788890701849 ; , s. 2411-2415
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Konferensbidrag (refereegranskat)abstract
- The purpose of this work is to present a quantitative comparison between three Method-of-Moments based domain decomposition techniques that are used for the analysis of large, disjoint finite antenna arrays. The methods considered are the Characteristic Basis Function Method, the Domain Green's Function Method, and a newly proposed improved version of the DGFM, i.e., the i-DGFM. The computational complexities of the techniques are compared in terms of runtime and memory usage. Both active and passive antenna arrays are considered.
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| 17. |
- Maaskant, Rob, 1978, et al.
(författare)
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Characteristic Basis Function Analysis of Large Aperture-Fed Antenna Arrays
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 9788890701849 ; , s. 2427 - 2431
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Konferensbidrag (refereegranskat)abstract
- The Characteristic Basis Function Method (CBFM) is applied to rapidly compute the impedance and radiation characteristics of electrically large aperture-fed antenna arrays. A stationary formula for the antenna input admittance matrix is expressed in terms of a product of matrix blocks that are readily available from a method of moment formulation. Numerical results are shown for large arrays of waveguide antennas requiring more than 2 million basis functions, which is reduced by a factor of 9000, so that the solution for the currents are still obtainable in-core on a single desktop computer, while being orders faster than commercial software codes or a standard MoM approach, provided that sufficient memory is available for the Gaussian elimination.
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| 18. |
- Mitchell-Thomas, R. C., et al.
(författare)
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The anti-fish eye cloak for surface wave antennas
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 9788890701849 ; , s. 267-268
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Konferensbidrag (refereegranskat)abstract
- In this paper a new lens, named the anti-fish eye lens, is proposed and its relation to the Maxwell fish eye lens is described. This novel lens is then applied to cloak an object positioned underneath it, to electromagnetic waves that are confined to the surface. The performance of the lens in reforming the cylindrical wave fronts is illustrated with numerical simulations. This lens has direct applications for surface wave antennas that are conformal to curved structures to remove the influence of the curvature, the consequence of which would detrimentally affect the directivity because of the distortion of the wavefronts. Therefore, using this technique, the performance of surface wave antennas on curved surfaces can be equivalent to those on flat surfaces.
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| 19. |
- Prinsloo, D., et al.
(författare)
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A Quad-Mode Antenna for Accurate Polarimetric Measurements Over an Ultra-Wide Field-of-View
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 9788890701849 ; , s. 3260 - 3263
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Konferensbidrag (refereegranskat)abstract
- The polarimetric performance of a quad-mode antenna element, consisting of a pair of crossed dipoles and an integrated monopole fed by a quadraxial transmission line, is analysed. Results are compared to a conventional dual-polarised antenna consisting of two orthogonal dipoles. The presented study shows that the quad-mode antenna effectively doubles the polarimetric capabilities of a dual-polarised antenna over the hemispherical field of view.
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| 20. |
- Quevedo-Teruel, Oscar, et al.
(författare)
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Conformal surface lenses from a bed of nails
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 9788890701849 ; , s. 269-270
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Konferensbidrag (refereegranskat)abstract
- This paper presents a validation of a fast method for calculating the propagation constant of a periodic bed of nails structure. These results are compared to full wave simulation results, showing good agreement. This method is then employed to design a Luneburg lens which is conformal to the surface of a sphere. The index distribution required to create this conformal lens was calculated using an optical path technique. This work has applications for the design of communication systems for vehicles and airborne platforms.
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| 21. |
- Razavi, Seyed Ali, et al.
(författare)
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Design of 60GHz Planar Array Antennas Using PCB-based Microstrip-Ridge Gap Waveguide and SIW
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 1825-1828
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Konferensbidrag (refereegranskat)abstract
- A wideband 2×2-slot element for a 60 GHz antenna array is designed by making use of two double-sided printed circuit boards (PCBs). The upper PCB contains the four radiating cavity-backed slots backed by a substrate-integrated waveguide (SIW) cavity. The SIW cavity is excited by a coupling slot fed by a microstrip-ridge gap waveguide formed in the air gap between the upper and lower PCBs. The designed 2×2-slot element is considered in an infinite array environment. A sample 32×32 slot array aperture is simulated using infinite array approach and the relative bandwidth of 16% over 57-66GHz frequency range with the directivity of more than 38 dBi over the operating bandwidth is obtained. The simulations are verified by measurements on a smaller 4×4 slot array surrounded by dummy elements.
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| 22. |
- Xiaoming, Chen, 1983, et al.
(författare)
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Comparing Throughputs of 2×2 Spatial Multiplexing MIMO Systems with and without CSI at the Transmit Side in Rich Isotropic Multipath Environments
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 3493-3494
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Konferensbidrag (refereegranskat)abstract
- Multiple-input multiple-output (MIMO) systems are attracting more and more attention due to the need of high spectral efficiency. Simple yet accurate throughput models are highly desired for studying the MIMO performance. MIMO throughput models based on the threshold receiver have been studied in [1], [2]. Specifically, a single-input multiple-output (SIMO) throughput model based on the concept of the threshold receiver was presented in [1]. The SIMO throughput model was extended to MIMO systems with full spatial multiplexing in [2], where only the open-loop configuration is studied.
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| 23. |
- Xiaoming, Chen, 1983, et al.
(författare)
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Revisiting the Complex Correlation in a MIMO System
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 2735 - 2739, s. 2735-2739
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Konferensbidrag (refereegranskat)abstract
- It is commonly believed that a complex correlation of up to 0.5 in magnitude is negligible for multiple-input multiple-output (MIMO) performances and that the correlation affects the diversity gain or throughput only via its magnitude. In this work, we show that when the number of antenna ports is larger than two, the phase of the correlation coefficient affects the diversity gain and that even small correlation can severely degrade the throughput performance of MIMO systems with full spatial multiplexing and no diversity gain. We assume maximum ratio combining (MRC) to investigate the correlation effect on diversity gain and zero-forcing (ZF) equalizer to study the correlation effect on the MIMO throughput.
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| 24. |
- Yaghjian, A. D., et al.
(författare)
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Quality factor for lossy and lossless antennas
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - : IEEE. - 9788890701849 ; , s. 3123-3127, s. 3123-3127
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Konferensbidrag (refereegranskat)abstract
- Lower-bound formulas for the Q of electrically small antennas in an arbitrarily shaped volume are derived for combined electric and magnetic dipole moments excited by both electric and magnetic surface currents as well as by electric surface currents alone. With either excitation, separate formulas are found for the dipole antennas containing only lossless (or ’nondispersive-conductivity’) material and ’highly dispersive lossy’ material. The formulas involve the quasi-static electric and magnetic polarizabilities of the associated perfectly conducting volume of the antenna, the ratio of the powers radiated by the electric and magnetic dipoles, and the efficiency of the antenna.
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| 25. |
- Yang, Jian, 1960, et al.
(författare)
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Arrangements and Applications of Self-grounded Antennas
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 79 - 83
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Konferensbidrag (refereegranskat)abstract
- The self-grounded antenna is a new type of compact ultra-wideband antennas with simple geometries. One of the characteristics of this type antenna is its high flexibility: the configuration of the antenna can be arranged in many different ways for different applications. In this paper, we overview the typical arrangements of the self-grounded antennas, and their performance for different applications.
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