Columbia University’s Harish Krishnaswamy, an electrical engineering graduate from the Indian Institute of Technology -Madras, has for the first time combined a non-reciprocal circulator and a full-duplex radio on a nanoscale silicon chip to develop the innovative system.
Krishnaswamy, director of the Columbia High-Speed and Mm-wave IC (CoSMIC) Lab said, “This technology could revolutionise the field of telecommunications. Our circulator is the first to be put on a silicon chip, and we get literally orders of magnitude better performance than prior work.” “Full-duplex communications, where the transmitter and the receiver operate at the same time and at the same frequency, has become a critical research area and now we have shown that Wi-Fi capacity can be doubled on a nanoscale silicon chip with a single antenna. This has enormous implications for devices like smartphones and tablets,” he noted. “Being able to put the circulator on the same chip as the rest of the radio has the potential to significantly reduce the size of the system, enhance its performance, and introduce new functionalities critical to full duplex,” added co-researcher Jin Zhou. To create their device, Krishnaswamy’s team had to ‘break’ Lorentz Reciprocity. This is a fundamental physical characteristic of most electronic structures that needs electromagnetic waves travel in the same manner in forward and reverse directions. “We wanted to create a simple and efficient way, using conventional materials, to break Lorentz Reciprocity and build a low-cost nanoscale circulator that would fit on a chip,” said PhD student Negar Reiskarimian, who developed the circulator. “It is rare for a single piece of research, or even a research group, to bridge fundamental theoretical contributions with implementations of practical relevance. It is extremely rewarding to supervise graduate students who were able to do that,” said the Indian-origin engineer who has won many accolades for his research efforts in the past. The team’s now working to improve the device further and hopes that the chip will be commercially exploited soon. The paper was presented at the “2016 IEEE International Solid-State Circuits Conference” in San Francisco, California, recently and the research was published in the journal Nature Communications.
