Frequency-Comb-Enabled Intelligent Sensing in Millimeter-Wave and Terahertz

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Silicon-based integrated circuits for generating and detecting millimeter-wave (mm-wave) and terahertz (THz) electromagnetic waves have enabled a variety of new technologies in radars, security, imaging, and spectroscopy. The objective of this project is to develop a novel integrated radar to perform broadband coherent sensing over a wide range of mm-wave/THz frequencies. This research project will result in enhanced intelligent sensors that can be trained to recognize certain objects with specific properties. The mm-wave and THz electromagnetic waves can penetrate through objects and provide us with depth information as well. A real-time intelligent sensor, which is trained with mm-wave/THz footprints of numerous objects, has a great potential to be used for many applications such as security imaging/sensing and autonomous driving. THz imaging and sensing systems not only can bolster homeland security with accurate detection of hidden objects and explosives, but also can prevent tens of thousands of lives lost in car accidents every year with increased accuracy of collision avoidance automotive radars. In addition to pushing the boundaries of THz technology, this project will train undergraduate and graduate students to become experts in THz research and make impacts to the future semiconductor industry in the United States. The principal investigator (PI) will also organize workshops to K-12 students and provide internship opportunity to high-school teachers. The research work will have two highly integrated thrusts. In the first thrust, a novel comb-based radar device that can perform broadband coherent detection and sensing in the THz frequency range will be designed, fabricated, and tested. This device will be designed based on recent transmitter and receiver chips that were developed in PI’s laboratory. These chips offer THz frequency combs with very narrow linewidths of a few hertz. The hertz-level accuracy of the measured comb tones indicates high stability of the frequency comb making it suitable for spectroscopy applications. The proposed spectroscopy system will expand the frequency range to 600 GHz. The first thrust will result in a fully integrated radar chip. To improve the sensitivity of the receiver, an array will be implemented. Each array element will consist of a broadband receiver quipped with an on-chip antenna. The radar sensor will be used to measure the frequency response of numerous objects over a wide range of frequencies. The second thrust is to develop an intelligent object recognition system by using the measurement data generated in the first thrust. The project will use machine learning algorithms to classify objects based on their interactions with broadband THz signals so that arbitrary objects can be categorized according to their THz transmittance data. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.