Issue link: https://iconnect007.uberflip.com/i/981887
MAY 2018 I DESIGN007 MAGAZINE 17 Shaughnessy: John, is there anything you'd like to add? Hendricks: I would just say that everything I've heard has been correct. The millimeter wave does present a lot of challenges, purely from the RF point of view, as has been pointed out. Millimeter wave is nothing new. Not even any- thing new in consumer applications because you'll see millions of 77-gigahertz radars being produced every year for the automotive indus- try now, and things like adaptive cruise control. So, from the RF point of view, it's not such a huge challenge. But people are developing new modulation technologies and all kinds of stuff that go with that, which is completely new. From the PCB side of things, it's the com- plexity of the boards at those frequencies that's rather new. Even the 77-gigahertz radar is a relatively simple PCB, compared to some of the designs we are starting to see coming along in 5G. The only other thing that I would point out is when we talk about sub-six gigahertz versus millimeter wave; it's going to be a long time before the millimeter wave really grows that quickly. The initial applications look more like fixed broadband access, and people are work- ing on mobile applications at millimeter wave, so that is a lot more challenging. In the initial, let's say, five-year period, the vast majority of 5G designs are not going to be millimeter wave, at least in terms of production volumes. They're going to be down below six gigahertz. Shaughnessy: Sounds like pretty interesting stuff. It sounds like it's going to make some little disruption, every step of the way. More change. Hendricks: It's the one thing that never changes. Shaughnessy: Well, I appreciate all of you join- ing us for this talk. I know you're all busy. Jordan: You too, Andy. Thank you. DESIGN007 Tech Bends Light More Efficiently, Offers Wider Angles for Light Input Engineering and physics researchers at North Car- olina State University have developed a new technol- ogy for steering light that allows for more light input and greater efficiency. At issue are diffraction grat- ings, which are used to manipulate light in everything from electronic displays to fiber-optic communication technologies. "Until now, state-of-the-art diffraction gratings configured to steer visible light to large angles have had an angular acceptance range, or bandwidth, of about 20 degrees, meaning that the light source has to be directed into the grating within an arc of 20 degrees," says Michael Escuti, a professor of electri- cal and computer engineering at NC State and corre- sponding author of a paper on the work. "The practical effect of this - in augmented-reality displays, for example - would be that users would have a greater field of view; the experience would be more immersive," says Escuti. The new grating achieves the advance in angular bandwidth by integrating two layers, which are super- imposed in a way that allows their optical responses to work together. One layer contains molecules that are arranged at a "slant" that allows it to capture 20 degrees of angular bandwidth. The second layer is arranged at a different slant, which captures an adja- cent 20 degrees of angular bandwidth. "The next step for this work is to take the advan- tages of these gratings and make a new generation of augmented-reality hardware," Escuti says.