There is a growing interest in low-cost, compact, and power-efficient terahertz (100GHz~10THz) integrated systems. Many biomedical and security applications, such as breath analyzer for disease diagnosis and handheld scanner for weapon detection, will flourish if such on-chip systems are realized. This mission is acknowledged to be extremely challenging due to the limited device speed and excessive passive loss. But what has been neglected for long is that the capability of the devices is also not fully released in many widely-used electronic designs.
In this talk, a fundamental approach is introduced which treats the THz circuit design as a problem of electromagnetic wave synthesis. The wave propagation and reflection are manipulated inside a linear media, and devices (e.g. transistor) are utilized as nonlinear, active boundary conditions. In specific, I will present (i) how to reach the device fundamental limits using the optimized synthesis of wave patterns, and (ii) how to efficiently guide multi-harmonic signals using the orthogonality of different wave modes. Based on such approach, the THz CMOS chip prototypes (harmonicoscillator, frequency doubler and radiator array) have demonstrated the highest radiated power and multiplier output frequency among all CMOS works. The proposed approach can also be applied into 2-D domain and emerging device materials (e.g. GaN). Finally, I will briefly present a fully-integrated THz CMOS imaging array based on a novel high-speed Schottky diode structure. The sensitivity at 300GHz is the highest among all silicon works without silicon lens or wafer thinning. This research work not only opens up a new way of reaching the limits of electronics, but also lays a solid foundation for future THz systems in imaging, spectroscopy and inter/intra-chip communications
Ruonan Han received the B.Sc. in microelectronics from Fudan University in 2007, the M.Sc. in electrical and computer engineering from the University of Florida in 2009, and the Ph.D. from Cornell University in 2014. His doctoral research is focused on high-performance terahertz signal generation and detection integrated circuits using CMOS and GaN technologies. In the summer of 2012, he was an intern with Rambus Inc., Sunnyvale, CA. He has authored or coauthored over 20 journal and conference publications. Han is the member of the IEEE Solid-State Circuits Society (SSCS) and the IEEE Microwave Theory and Technique Society (MTT-S). He serves as a reviewer for the IEEE Trans. Microwave Theory and Tech. (T-MTT) and the IEEE Intl. Symp. on Circuits and Systems (ISCAS). He was the winner of the Cornell ECE Innovation Award (2013), the Best Student Paper Award (2nd) of the Radio-Frequency Integrated Circuits (RFIC) Symp. (2012), and the Helic Student Scholarship of the Custom Integrated Circuits Conf. (CICC) (2010). He was also the recipient of the John M. Olin Fellowship (2010), the Irwin and Joan Jacobs Fellowship (2011), and the IEEE Solid-State Circuits Society Pre-Doctoral Achievement Award (2013).