ECE graduate student Peiyu Chen won best paper at the 2015 IEEE Radio and Wireless Symposium (RWS) Student Paper Competition. He is a Ph.D. student in the Rice Integrated Systems and Circuits (RISC) laboratory directed by professor Aydin Babakhani. Chen’s work, “A 30GHz Impulse Radiator with On-Chip Antennas for High-Resolution 3D Imaging,” is novel in its use of impulse to generate 3D images.
“Peiyu has designed a miniaturized impulse-radiating chip, successfully tested it, and developed novel signal-processing algorithms to produce 3D radar images with spatial resolution of better than 1mm. Recently, we have received a lot of interest from industry to apply this technology in the defense and energy sectors,” Babakhani said.
The benefit of using pulse-based imaging is that there is more information produced compared to continuous-wave-based imaging. Pulse-based measurement provides precise timing information that continuous wave cannot. Timing information is used to extract both depth and angular resolution of a distributed object in a 3D space.
“We are the first to do this, using impulse to generate high-resolution 3D images, by using silicon-based integrated circuits. No one has shown radar images with this level of spatial resolution using impulse radiating chips,” Chen explained.
The team uses the concept of beam-forming synthetic radar array with instantaneous bandwidth of more than 30GHz. The benefit of the array is that it can increase the signal-to-noise ratio (SNR) and also the imaging resolution compared with a single radiator.
“We want to show that the chip we designed has the capability to image two small objects placed very close to each other. It can also be used to produce high-resolution 3D images of a distributed object,” Chen said.
Another important feature of Chen’s work is the high depth resolution.
“We implemented a novel architecture of an asymmetric voltage-controlled-oscillator (VCO) integrated with a broad-band on-chip antenna that produces impulses with very small jitter on the order of several hundred femtosecond (10-15 s). This is equivalent to a depth resolution of less than 100 microns. It means that our designed chip can measure depth with 100 microns accuracy,” Chen explained.
Chen’s research has many important applications, including 3D radar imaging for security scanning, gesture capture in gaming consoles, collision avoidance radars, and high-resolution logging in the Oil/Gas industry.
“For gaming consoles like the Wii, we can use this chip to capture players gesture. If they raise their hand, the chip can locate their hand and do the 3D imaging to capture their movements. It is also useful for security screening at the airports,” Chen said.
Chen traveled to San Diego with other finalists to attend the RWS conference and present his work. This is the second Best Paper Award for Babakhani's team, the first being Mahdi Assefzadeh's win in June at the International Microwave Symposium Student Paper Competition.