Dec 8 (Thu) @ 3:00pm: “High Efficiency Sub-THz Transmitter,” Jeff Chien, ECE PhD Defense

Date and Time
Engineering Science Building (ESB), Room 2001


D-band (110-170 GHz) and G-band (140-220 GHz) phased array transceivers have gained more attention for automotive radar and beyond-5G communication systems in recent years due to the high resolution for imaging and wide available bandwidth for high data rate applications. The limited fT /fmax of CMOS technologies, even with scaled devices places a significant circuit design challenge, for power amplifiers (PAs) and, moreover, transmitters since low efficiency is found not only in the PA but also high loss in mixers and multipliers in local oscillator (LO) path.

In this defense, the design methodology of high efficiency Sub-THz transmitter and building blocks in 22-nm FDSOI CMOS and InP HBT process will be covered. The talk will include D-band multi-way power combined PA in 22-nm FDSOI CMOS, high efficiency D-band and G-band PA designs in InP HBT, D-band and G-band switches design in InP HBT as well as D-band high efficiency outphasing transmitter in 22-nm FDSOI CMOS.


Jeff Chien received the B.S. and M.S. degrees in EECS and EE from National Tsing Hua University in 2014 and 2015, respectively. During 2015 to 2018, he was with Airoha Technology Corporation. In 2020 and 2022, he joined Qualcomm and Analog devices as an intern. He is now pursuing Ph.D. degree at University of California, Santa Barbara and his current research focuses on mm-wave transmitter and power amplifier designs.

Hosted by: Professor James Buckwalter

Submitted by: Jeff Chien <>