| 1. |
- Beukman, T. S., et al.
(författare)
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Modal considerations for synthesizing the tapering profile of a quadruple-ridged flared horn antenna
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 488-491
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Konferensbidrag (refereegranskat)abstract
- A technique is proposed to synthesize the ridge taper of a quadruple-ridged flared horn (QRFH) antenna. By considering the modal propagation in the horn it is possible to improve the antenna performance. A QRFH is designed for an offset Gregorian reflector system and produces an aperture efficiency above 50% across the entire operational bandwidth (6:1).
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| 2. |
- Gustafsson, Mats, et al.
(författare)
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An overview of stored electromagnetic energy
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 793-795
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Konferensbidrag (refereegranskat)abstract
- Although, the stored electromagnetic energy of an antenna is used to determine the antenna Q, it is difficult to define the stored energy. The stored energy can be estimated from the input impedance of the antenna, the electromagnetic fields around the antenna, and the current densities in the antenna structure. These estimates are similar but not equal for all antennas. Here, the different approaches to determine the stored energy are discussed.
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| 3. |
- Ivashina, Marianna, 1975, et al.
(författare)
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Optimization of the 0.35-1.05 GHz Quad-Ridged Flared Horn and Eleven feeds for the Square Kilometer Array baseline design
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 513-516
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Konferensbidrag (refereegranskat)abstract
- Initial optimization results for the wide-band Eleven antenna and Quadruple-Ridged Flared Horn (QRFH), designed to operate as the reflector antenna feeds at 350 - 1050 MHz, are presented and discussed in the context of the next generation radio telescope - the Square Kilometer Array (SKA). First, we describe the procedure that has been developed to carry out time-efficient optimization of the feeds for multiple antenna optics configurations at the system level (so as to maximize the antenna-receiver sensitivity), and then cross-compare the two feed types by assessing the main antenna system characteristics and radio-astronomy performance metrics.
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| 4. |
- Ludick, D. J., et al.
(författare)
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Accelerating the Domain Green's Function Method through adaptive cross approximation
- 2014
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Ingår i: Proceedings - 16th International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 636-639
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Konferensbidrag (refereegranskat)abstract
- © 2014 IEEE. The Domain Green's Function Method (DGFM) is a Method-of-Moments (MoM) based domain decomposition approach that is useful for the analysis of large, irregular antenna arrays. Mutual coupling between array elements is accounted for with the formulation of an active impedance matrix equation for each of the domains/array elements. The active current distribution on the entire array geometry is then obtained by solving these smaller matrix equations pertaining to the elements. The active impedance matrix calculation entails a summation of the MoM matrix diagonal and off-diagonal sub-matrices. For arrays containing a large number of elements this summation can lead to matrix fill times similar to that of the global MoM calculation. To mitigate this significant computational overhead, while still maintaining a sufficient degree of accuracy, the adaptive cross approximation (ACA) algorithm is applied to accelerate this part of the DGFM.
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| 5. |
- Ludick, D. J., et al.
(författare)
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Applying the NGF-enhanced Domain Green's Function Method to the analysis of antenna arrays and ground planes of finite sizes
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 632-635
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Konferensbidrag (refereegranskat)abstract
- In this work, antenna arrays will be analysed in the presence of ground planes that are both of finite extent. A hybrid approach between a partitioned MoM scheme called the Numerical Green's Function (NGF) and the Domain Green's Function Method (DGFM) is presented, viz., the NGF-enhanced DGFM. The method allows for computationally efficient simulations, in that various array configurations can be investigated without solving again the part of the problem associated with the ground plane.
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| 6. |
- Prinsloo, D.S., et al.
(författare)
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Beamforming strategies for active multi-mode antennas: Maximum gain, Signal-to-Noise ratio, and polarization discrimination
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 507-510
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Konferensbidrag (refereegranskat)abstract
- The performance of a dual-polarized quad-mode antenna, representing a potential array antenna element for wide scan-angle applications, is assessed. This analysis is carried out by investigating the utilization of the four available Transverse Electromagnetic (TEM) excitation modes, when beamforming for maximum gain, Signal-to-Noise ratio (SNR), and polarization discrimination whilst retaining minimum noise.
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| 7. |
- van Ardenne, Arnold, 1948, et al.
(författare)
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A dense aperture array with photonic beamforming for radio astronomy
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 856-859
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the design and technologies of photonic beamformers relevant for use in the context of the socalled dense aperture arrays for the Square Kilometre Array[1]. The photonic beamformer approach complements the more conventional albeit state-of-the art RF and digital beamforming approach presently projected and the work aims to identify relevant design and technology issues for future use. This paper addresses these and presents the photonic design approach on a 36 element demonstrator array for possible use with the SKA of a 4:1 frequency bandwidth, UHF-band array having millions of elements.
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| 8. |
- Young, A., et al.
(författare)
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Toward a practical demonstration of physics-based beam calibration models - CBFPs and the LOFAR-LBA antenna array radio telescope
- 2014
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Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 462-465
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Konferensbidrag (refereegranskat)abstract
- We consider the application of the Characteristic Basis Function Pattern (CBFP) method to calibrate for direction-dependent gain effects of the LOFAR Low Band Antenna (LBA) array. The use of array-based calibration models, as opposed to element-based calibration models, is proposed in order to reduce the number of solvable beam model parameters.
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