1. a Department of Electrical Engineering, KAIST , 291 Daehak-ro, Yuseong-gu, Daejeon , 305-701 , South Korea
2. b RF and Satellite Payload Research Team, ETRI , 138 Gajeong-ro, Yuseong-gu, Daejeon , 305-700 , South Korea
3. c Department of Electrical Engineering , Universiy of Seoul , 13 Siripdae-gil, Dongdaemun-gu, Seoul , 130-743 , South Korea