Usually removing hardware means removing functionality. But a team of researchers from Columbia University has created a new kind of Wi-Fi chip that uses just one antenna rather than two — and yet manages to be just as fast. The team, led by Professor Harish Krishnaswamy, has been working on the concept of what they call "circulators" for a while now. Wi-Fi chips normally have two antennae: One to receive, the other to transmit. By removing an antenna, it's be possible to shrink the chip significantly — but it also cuts the speed as you can only send or receive.
The team's circulators, however, use rapid switching, echo cancellation and filters to use a single antenna to both send and transmit the data at the same time. The new chip can therefore work twice as fast as other single-antenna Wi-Fi systems, which can only send or receive at any given moment. Or to put it another way, it's smaller than regular Wi-Fi chips but just as fast.
Now, they have managed to shrink the circuitry down to the scale at which they can build it on a regular silicon chip. Krishnaswamy explains in a press release:
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've shown that WiFi capacity can be doubled on a nanoscale silicon chip with a single antenna. This has enormous implications for devices like smartphones and tablets.
The chip is the small black square on the board in the picture. The team is working to improve the device further, but hopes the approach will be used in real devices in the future.