Woojin Chang received his BS and MS degrees in information engineering from Korea University, Sejong, Rep. of Korea, in 1996 and 1998, respectively, and his PhD degree in electronic engineering from Chungnam National University, Daejeon, Rep. of Korea, in 2008. From 1998 to 1999, he worked as a research engineer in LG Precision, Yongin, Rep. of Korea, where he was engaged in R&D on power amplifier modules for wireless communications. In 1999, he joined Electronics and Telecommunications Research Institute, Daejeon, Rep. of Korea, where he is currently a principal research member. Recently, his main research interests are MMICs and devices of compound semiconductors, such as GaN, GaAs, InP and SiGe.