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Electrical and Computer Engineering

RISC Lab Featured in IEEE Microwave Magazine

Congratulations to Rice Electrical and Computer Engineering graduate students Himanshu Aggrawal, Peiyu Chen, Mahdi Assefzadeh, and Babak Jamali, and faculty member Aydin Babakhani, who are featured in the December issue of IEEE Microwave Magazine for their research accomplishments in millimeter wave and terahertz frequencies.

2016.11.Babakhani.IEEEMWIn the article, which can be read here, the group discusses their research and discusses the history of generation and detection of electromagnetic waves, and current trends in the field. They also reviewed some applications of picosecond generators and detectors, and reported silicon-based sources and detectors capable of generating and detecting picosecond pulses with high stability.

The technology for generating and detecting electromagnetic waves has evolved significantly over the last 120 years, the team explained. In the early 1890s, Guglielmo Marconi used a spark-gap transmitter to build a wire-less telegraphy system. Marconi’s design used the spark gap as a fast high-voltage switch. The technology for generating electromagnetic waves then evolved further with the invention of vacuum tubes in the mid- 1920s. During the second half of the 20th century, spurred by the birth of transistors and integrated circuits, the cost of producing electromagnetic signals in the gigahertz range was greatly reduced. This resulted in the birth of cellular networks for consumer applications.  Over the past decade, the team noted, there has been a significant shift toward millimeter- wave and terahertz frequencies due to advances in source/detector technologies and the rapidly rising demand for wireless data.

The group discusses their work in pulse-based imaging systems and picosecond generators and detectors. In a pulse-based imaging system, an array of radar transmitters fires pulses such that they arrive at a desired location in 3-D space at the same time. Picosecond generators and detectors enable 100+-Gb/s wireless communication, high-resolution 3-D imaging radars for security monitoring and autonomous driving, miniaturized radars for gesture detection and touchless smartphones, and spectrometers for explosive detection and gas sensing. The paper touches on Peiyu Chen's theoretical and simulation study of the Nonlinear Q-Switching Impedance Technique (NLQSI) to produce and radiate picosecond pulses. The article also reviews  Mahdi Assefzadeh's trigger-based beamforming technique. By using this technique, the distortive effects of the conventional narrowband method are eliminated by separating the delay path from the information path.

The group summed up their work in the following way: The generation and detection of electromagnetic waves have evolved from Marconi’s first spark-gap method to today’s state-of-the-art solid-state picosecond pulse radiators. Picosecond generators and detectors enable wireless communication at 100+ Gb/s, high-resolution 3-D imaging radars for security monitoring and autonomous driving, miniaturized radars for gesture detection and touchless smartphones, spectrometers for explosive detection and gas sensing, precision time/ frequency transfer, wireless synchronization of widely spaced arrays, and secure LOS communication.