M. Mahdi Assefzadeh and his advisor, Aydin Babakhani, won Best Paper out of more than 30 finalists, and Himanshu Aggrawal and Babakhani won Honorable Mention (fourth), at the IEEE Microwave Theory and Techniques Society (MTT-S) Student Paper Competition. They presented at the International Microwave Symposium in Tampa on June 6. Both Rice students were selected as finalists in April (one of only two universities in the world to have more than one student finalist).
Assefzadeh, whose paper is titled, “An 8-psec 13dBm Peak EIRP Digital-to-Impulse Radiator with an On-chip Slot Bow-Tie Antenna in Silicon,” is working on a type of real-life Terahertz vision. “My focus is on radiating short pulses carrying high-power THz waves. The benefit of ultra-short (sub-8psec) pulses is that you can separate signals reflected from different parts of a single object in time-domain. This helps us to produce high-resolution THz images from various dielectric and metallic objects. The most important factor of my work is that the impulse radiator is fabricated using a silicon-based process technology. This is inexpensive, light and small. You can imagine one day every smart phone is equipped with a high-resolution THz camera,” he said. The challenge is to generate short pulses in the time-domain with high peak power.
"Mahdi currently holds the world record for generating and radiating the shortest pulse using a silicon-based technology. This is an 8psec pulse. The previous record was about 30-40psec,” Babakhani said.
Assefzadeh’s work, funded by the Department of Defense through a Young Faculty Award, can potentially benefit a wide array of industries.
“One of the applications of his work is high-resolution 3-D THz imaging that can be used for medical applications. If doctors had a chip like this in the camera on their phones, they could use it to distinguish between a cancerous tissue and a normal one. Other important applications are security cameras, 3-D imaging devices for gaming consoles, and high-speed wireless communication links. It could also be used in high-resolution logging applications for the oil and gas industry, giving a clearer picture of the reservoirs,” Babakhani said.
“One of my biggest inspirations in choosing engineering for my graduate studies is my dad who is a flight engineer himself. He showed me the world of engineering,” Assefzadeh said.
He hopes to continue his career in academia. “In this field, you design something then test it. If it doesn’t work the first time – and most of the time that is what happens – I keep working on it until I get satisfactory results. I enjoy the process and that drives me. This high-impact research mostly happens in universities.”
Watch him discuss his work (in less than 90 seconds) here.
Aggrawal wrote a paper titled, “A 40GS/s Track-and-Hold Amplifier with 62dB SFDR3 in 45nm CMOS SOI,” designed an Analog Digital Converter (ADC) chip. “Everything around us is analog,” he explained. “Your voice when you speak is analog. If you are talking on a cellular phone, there is an ADC chip inside the phone to convert your voice to a digital signal. Digital is used because it is easier – you can process data more quickly.” This ADC architecture is particularly impressive because it uses Active Cancellation to mitigate the leakage caused by parasitic capacitance at high frequencies. This mitigation makes the chip faster and more accurate. “He uses a symmetrical design to increase isolation, which in turn increases the performance,” Babakhani, his advisor, added. These chips are in everything and are the future of high-speed electronics,” Aggrawal said. “Phones, computers, airplanes, satellites – everywhere."
Aggrawal’s path to Rice led through his undergraduate university – India Institute of Technology (IIT). As an undergraduate, he was part of a team that successfully built and launched a nano-satellite to space – one that is still operable today.
"Students from Rice came to IIT and we had a lot of interactions. They kept talking about Rice and how good it is,” he said. “But the real deal that drove me here was my advisor (Babakhani). I knew under his mentorship I would flourish. And Houston is a very good place to be – I am a big NASA junkie."
“NASA represented hopes and aspirations….that mankind could go beyond Earth. This hope inspired millions of scientists. It’s now time to come up with something, something that can inspire similar hopes and aspirations, and I want to be a part of it.”
He continued, “I realized my passion early. My father was a Mechanical Engineer and he helped me pursue my dreams. My hobby turned into a passion which turned into a profession, and now it has turned into madness and I cannot live without it. My advice to others thinking about Rice ECE for their education would be – find your own madness. If you find it, you will be happy.”
Along with classmate Babak Jamali, Aggrawal received a scholarship to the competition that covered his travel and housing.