Cheaper Microwave Technology Could Make Self-Driving Cars a Faster Reality

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Researcher Daryoush Shiri and his team at University of Waterloo have conceptualized a method of emitting high-frequency microwaves using inexpensive silicon to replicate what’s known as the “Gunn Diode.” His findings could drastically reduce costs of current methods which are reliant on gallium arsenide, a toxic compound that is expensive and cumbersome to utilize.

Researchers using computational nanotechnology have found a way to utilize inexpensive silicon to emit high-frequency microwaves, something that was thought to be impossible until now.

Right now, the only way to generate microwaves is with something called a “Gunn Diode.”

According to a study published by Scientific Reports, “When voltage is applied to gallium arsenide and then increased, the electrical current running through it also increases — but only to a certain point. Beyond that point, the current decreases, an oddity known as the Gunn effect that results in the emission of microwaves.”

This has to do with the molecular properties of gallium arsenide. Ordinarily, when direct voltage is applied to a conductor, the mobility of electrons increases and thus the current flowing through the conductor increases as well. Conversely, when the same voltage applied to gallium arsenide is increased, the mobility of electrons decreases. The result is the generation of high-frequency alternating current and the emission of microwaves.  

The catch with gallium arsenide is that it’s toxic, and the equipment to harness it (semiconductors, for example) is bulky and expensive. This restriction results in existing technologies utilizing Gunn Diodes to appear less than pleasing to the eye, not to mention costly.

Take autonomous vehicle technology for example.  The arrays of sensors in self-driving cars use Gunn Diodes to emit microwave radiation that bounces off their environment, compiling data to create a map of surrounding objects. These sensor systems cost tens of thousands of dollars and sit on the tops of the vehicle like giant spinning robotic heads. Not very attractive. Or affordable.

To remedy this problem, Daryoush Shiri and his team of researchers at the University of Waterloo have used supercomputers to conceptualize the emission of microwaves by stretching silicon nanowires as voltage was applied to them. These nanowires are so thin that it would take 100,000 of them bundled together to equal the thickness of a single human hair.

Theoretically, Shiri’s research can make technologies such as police radars and sensors in autonomous driving cars cheaper by replacing the need for expensive gallium arsenide with inexpensive (and more compact) silicon.

An Opportunity Gap Within the Automotive Industry

1.25 million people die in automobile accidents annually, 94 percent of which are attributed to human error. Both the National Highway Traffic Safety Administration in the United States and the New Car Assessment Program in Europe have issued safety guidance for Automated Driving Systems (ADS) to automakers.

The push for ADS aims to reduce the percentage of motor vehicle crashes caused by human error, potentially saving hundreds of thousands of lives over the next few decades.

These new safety initiatives present massive opportunities for automakers. Several of the world’s largest automakers are investing billions in research and production in the race to bring safer vehicle technology to market. Toyota, for example, now includes automatic emergency braking (AEB) systems on almost all of their new models after 2017. Ford plans to roll out an entire fleet of fully autonomous vehicles by 2021.

The development of reliable radar units on fully autonomous vehicles is still in R&D stages, and there is no one-size-fits-all solution. Automakers are currently experimenting with innovative methods to introduce this technology into the mainstream. Using inexpensive silicon to emit microwaves may shortcut several challenges on the production line.

For example, according to CNN Money, Toyota has announced they plan to invest $2.8 billion to “form a new company dedicated to the research and development of self-driving vehicles.” And Ford, Honda, Volvo, and others are also investing billions of dollars in the race to bring a fully autonomous vehicle to market.

Regardless of which direction manufacturers are taking their ADS, the demand for cheaper sensor technology is there. Shiri’s complex computer models show that using silicon has the potential to significantly lower production costs of devices designed to emit high-frequency microwaves, allowing manufacturers to bring safer vehicles to market sooner.

The Future Looks Promising

The race is on, and automakers are investing big to find newer and cheaper autonomous driving solutions. And Shiri’s findings don’t stop at radar technology — his research team claims this is only the beginning. According to Shiri himself, “The stretching mechanism could also act as a switch to turn the effect on and off, or vary the frequency of microwaves for a host of new applications that haven’t even been imagined yet.”