• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1089-1097
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• 2002

In this paper, the novel shipboard Active Phased Array Antenna(APAA) system for maritime mobile satellite communications is introduced. The antenna uses novel technologies like wide range hybrid tracking, single antenna elements with both of Rx and Tx, asymmetrical array structure, interference isolation between Rx and Tx, and error correction method from frequency scan effect. The antenna has single aperture for both of Rx and Tx with 32 $\times$ 4 two-dimensional array. The antenna has two beams. Its frequencies are 7.25 ~ 7.75 GHz for Rx and 7.9 ~ 8.4 GHz for Tx. The antenna gains are 35.4 dBi for Rx and 35.7 dBi for Tx, those are 54 % of efficiency. The electrically steering ranges are $\pm$35$^{\circ}$ of elevation direction and $\pm$4$^{\circ}$ of azimuth direction. The mechanical control ranges at hybrid tracking capability are continuous 360$^{\circ}$ of azimuth direction and $\pm$10$^{\circ}$ of elevation direction. The antenna has 2.2$^{\circ}$ of 3 dB beamwidth, -14 dB of sidelobe level, and 21 dB of cross-pol suppression. The antenna performance was measured by near field measurement set. Its system performance was tested on the ship motion simulator and with the satellite transponder simulator. The test result showed that its tracking error was within -3 dB from its peak gain under motion condition. The antenna system was tested by real modulated Direct Broadcasting Satellite(DBS) signals to check its communication processing function.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.1
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• pp.50-60
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• 2021

For conventional AESA radars, DC-DC power modules using 300 Vdc have low efficiency, high volume, heavy weight, and high price, which have problems in modularity with T/R module groups. In this paper, to improve these problems, we propose a distributed DC-DC power module with high-voltage 800 Vdc and high-efficiency Step-down Converter. In particular, power requirements for modern and future marine weapons systems and sensors are rapidly evolving into high-energy and high-voltage power systems. The power distribution of the next generation Navy AESA radar antenna is under development with 1000 Vdc. In this paper, the proposed highvoltage, high-efficiency DC-DC power modules increase space(size), weight, power and cooling(SWaP-C) margins, reduce integration costs/risk, and reduce maintenance costs. Reduced system weight and higher reliability are achieved in navy and ground AESA systems. In addition, the proposed architecture will be easier to scale with larger shipboard radars and applicable to other platforms.