• Journal of Korea Society of Industrial Information Systems
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• v.20 no.1
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• pp.43-47
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• 2015

In this work, a broadband microstrip (MSL) - to - waveguide (WR12) transition has been presented for millimeter-wave module applications. For improvement of a bandwidth, the radial MSL electrical-probe is designed on the low-loss organic dielectric substrate. The designed and tested characteristics of the proposed transition are characterized in terms of an insertion and return loss. Considering the loss contribution of the cable adapter and waveguide transition for the measurement, the proposed transition loss can be analyzed as -1.88 and -2.01 dB per a transition at 70 and 80 GHz, respectively. The bandwidth of the proposed transition for reflection at -10 dB is 26 GHz at all test frequencies from 67 to 95 GHz. Compared to the state-of-the-art results, improvement of 8.3 % is achieved for the operation bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.87-94
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• 2008

This paper proposes a high-gain monopulse antenna using the folded reflectarray for a monopulse target-tracking radar systems designed at the center frequency of 94 GHz. In target-tracking radar systems, the angle of arrival of the incoming wave Is determined by comparing the signal received on two or more non-coincident antenna patterns. This is the physical basis of most target-tracking techniques and the comparison is made simultaneously in a monopulse radar systems. In this paper, the antenna consists of polarizing grid, reflectarray, multimode feed horn, and comparator implemented by wavguide. The antenna is able to have three radiation patterns by using the monopulse feed systems assembled by multimode feed horn and comparator. The antenna demonstrates maximum gains 36dB, 33.5dB and 27.2dB at sum mode, azimuth mode, and evevation mode respectively.