• Journal of Digital Convergence
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• v.11 no.12
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• pp.417-422
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• 2013

In this paper, the implementation of a null-steering antenna array using GPS patch antennas is suggested. The antenna array consists of five patch antenna elements fabricated on the ceramic substrate. The antenna element proposed here is a typical circular polarization patch and a prototype patch array antenna is manufactured on the PCB. The antenna has one reference element located at the center and other four elements are placed at the corners. A null in the direction of the jamming signal can be produced by changing the phases of 4-elements. Simulation results of the array antenna by CST MWS are presented and discussed. The basic performances are measured and the results are shown. The results show that the antenna presented here can be used to remove the signals from the directions of any jammers.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1050-1060
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• 2012

As an approach to high-efficiency of SOFC system, SOFC/GT Hybrid system is effective. However, if the output size of the system belongs to the marine class of dozens MWs, the introduction of the cooling system of GT system, which is used as sub-system, makes its related devices complicated and also makes its control difficult. Accordingly, for the marine use, SOFC/GT (non-cooling)Hybrid system looks more suitable than SOFC/GT(cooling)Hybrid system. This study established the SOFC/GT (non-cooling)Hybrid system, and examined the operating temperature & current density of the stack for the system, pressure ratio of the gas turbine, the influence of TIT(Turbine Inlet Temperature) on system performance, etc. through the simulation process. Through this research process, this study was able to confirm that electrical efficiency rises in spite of the increase in the required power for the air compressor, and there exists a limited range of temperatures for operation in TIT.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.318-325
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• 2019

As satellite communication technology with high efficiency and spatiality evolves, demands of customer for efficient and effective satellite broadcasting services are increasing due to interval reduction of the between satellites, and the limited radio-frequency spectrum resources. Recently, research on antenna that it possible to simultaneously receive multiple signal from various satellites while holding maintain the same number of previous reception channels by using the single reflector has been ongoing. It is necessary to be able to simultaneously receive signals from various satellites in order to maintain the same number of previous reception channels. We suggest a multiband antenna which can be simultaneously and independently receiving Ku band and Ka band satellite broadcasting signals transmitted by three adjacent satellites. We have designed and simulated using commercial design tools TICRA CHAMP and CST MWS to meet the target specifications. It appears that the antenna has -10 dB return loss, and more than 40 dBi directivity gain in Ku band and Ka band respectively.