Congratulations to Rice Electrical and Computer Engineering (ECE) PhD student Peiyu Chen on winning 2nd place in the Best Student Paper Award at the 2016 IEEE International Microwave Symposium (IMS). Chen is a member of Dr. Aydin Babakhani’s Rice Integrated Systems and Circuits (RISC) laboratory. His colleague, Xuebei Yang, was also a finalist in the same competition.
Chen’s paper proposes a new integrated circuit idea, nonlinear Q-switching impedance (NLQSI), which helps to generate an amplitude reconfigurable picosecond impulse. “NLQSI is a kind of smart circuit block. It senses the circuit and tunes itself adaptively. In this work, it is used to control the pulse amplitude, which is crucial for high speed communications links,” he said.
The designed silicon chip also radiates a world-record 4ps impulse. The pulse-width, 4ps, is also important, Chen noted, because shorter impulses produce images with better resolution. The research has many applications in security imaging, high-speed communications, and the oil & gas industry.
“If the image has better resolution, we can produce 3D radar images with better resolution,” he explained. “The shorter pulse has a broader frequency spectrum. Using it we can do better spectroscopy research and then potentially apply the research to detect more materials or explosives in an airport security check, for example.”
Apart from the new circuit idea, Chen’s paper demonstrates for the first time an optical-electronic-mixed measurement technique for picosecond pulse radiations from a silicon chip. In the proposed method, a photoconductive antenna detector is used with an asynchronous optical sampling (ASOPS) scheme, which is achieved by a commercial THz Time-Domain Spectroscopy (THz-TDS) system.
“The current electronic solutions for measuring picosecond pulses have many problems, such as limited bandwidth, measurement complexities of calibration along the entire receiver path. These problems make the current solutions very difficult to accurately measure picosecond pulses. Our proposed idea resolves these issues. This is the novelty of our work,” Chen said.
The current electronic solutions use a very fast sampling oscilloscope. The best one has the rising time of 4.5ps, which is not fast enough to measure the 4ps the group has achieved. Chen notes that the team will demonstrate high-speed wireless communication link, gas spectroscopy, and 3D radar imaging, based on the leading picosecond pulse generation techniques that RISC invented.
“In terms of circuit designs, for the next step we want to build a fully-integrated picosecond pulse transceiver. And we will also spend more time on the novel THz measurement technique,” he said.
Congratulations also to Himanshu Aggrawal, PhD student in ECE, for receiving the prestigious IEEE MTT-S Graduate Fellowship for 2016! Aggrawal is also a member of the Rice Integrated Systems and Circuits (RISC) laboratory, and was recognized for his work in next generation Terahertz (THz) millimeter wave technology.
“Himanshu is pushing the limits of high-speed samplers and receivers in the mm-wave regime with signal frequencies exceeding 60GHz. He is working on a novel nonlinear sampling idea that can reduce the sampling window to few picoseconds ” Babakhani said. To read more about Himanshu’s work, click here.