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Schuss J.J. Upton J. Myers B. Sikina T. Rohwer A. Makridakas P. Francois R. Wardle L. Kreutel W. Smith R. 《Aerospace and Electronic Systems Magazine, IEEE》1997,12(12):3-12
The design of a novel phased array panel that provides the L-band satellite to ground links for the IRIDIUM global communications system is presented. Key components and aspects of this phased array antenna are discussed, including the beamforming architecture, radiated intermodulation products, the patch radiators, and the T/R module. The strategy for minimizing DC power consumption over a large range of multicarrier rf output power is described. Finally, test results showing compliant array operation are summarized 相似文献
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Anthony R. Yeates Tahar Amari Ioannis Contopoulos Xueshang Feng Duncan H. Mackay Zoran Mikić Thomas Wiegelmann Joseph Hutton Christopher A. Lowder Huw Morgan Gordon Petrie Laurel A. Rachmeler Lisa A. Upton Aurelien Canou Pierre Chopin Cooper Downs Miloslav Druckmüller Jon A. Linker Daniel B. Seaton Tibor Török 《Space Science Reviews》2018,214(5):99
Seven different models are applied to the same problem of simulating the Sun’s coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated electric currents are developed in significantly different ways. This is not a direct comparison of the coronal modelling techniques, in that the different models also use different photospheric boundary conditions, reflecting the range of approaches currently used in the community. Despite the significant differences, the results show broad agreement in the overall magnetic topology. Among those models with significant volume currents in much of the corona, there is general agreement that the ratio of total to potential magnetic energy should be approximately 1.4. However, there are significant differences in the electric current distributions; while static extrapolations are best able to reproduce active regions, they are unable to recover sheared magnetic fields in filament channels using currently available vector magnetogram data. By contrast, time-evolving simulations can recover the filament channel fields at the expense of not matching the observed vector magnetic fields within active regions. We suggest that, at present, the best approach may be a hybrid model using static extrapolations but with additional energization informed by simplified evolution models. This is demonstrated by one of the models. 相似文献
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