Dr. Chen was with Transilica, Inc. (now Microtune, Inc.), in California, USA, where he was engaged in the design of differential low-noise amplifiers (LNA) and voltage-controlled oscillators (VCO) for Bluetooth applications. From 2005 to 2007, he collaborated with Sony Corporation, Japan in the area of high-frequency noise characterization of MOSFETs. In 2006, he collaborated with RF Micro Devices Inc. (RFMD) in California in high-frequency noise modeling and design of LNAs. Since 2005, he collaborated with United Microelectronics Corporation (UMC), Taiwan, R.O.C. to study the high-frequency noise characterization and modeling of the state-of-the-art CMOS devices for low-power, mobile applications and to investigate the reliability issues of LDMOS for high power applications.