Lyu F.,Duke University |
Cummer S.A.,Duke University |
Solanki R.,Duke University |
Weinert J.,Duke University |
And 8 more authors.
Geophysical Research Letters | Year: 2014
We report on the development of an easily deployable LF near-field interferometric-time of arrival (TOA) 3-D Lightning Mapping Array applied to imaging of entire lightning flashes. An interferometric cross-correlation technique is applied in our system to compute windowed two-sensor time differences with submicrosecond time resolution before TOA is used for source location. Compared to previously reported LF lightning location systems, our system captures many more LF sources. This is due mainly to the improved mapping of continuous lightning processes by using this type of hybrid interferometry/TOA processing method. We show with five station measurements that the array detects and maps different lightning processes, such as stepped and dart leaders, during both in-cloud and cloud-to-ground flashes. Lightning images mapped by our LF system are remarkably similar to those created by VHF mapping systems, which may suggest some special links between LF and VHF emission during lightning processes. © 2014. American Geophysical Union. All Rights Reserved.
Yurduseven O.,Integrated Plasmonics |
Imani M.F.,Integrated Plasmonics |
Odabasi H.,Integrated Plasmonics |
Gollub J.,Integrated Plasmonics |
And 4 more authors.
Progress in Electromagnetics Research | Year: 2015
The resolution of a frequency diverse compressive metamaterial aperture imager is investigated. The aperture consists of a parallel plate waveguide, in which an array of complementary, resonant metamaterial elements is patterned into one of the plates. Microwaves injected into the waveguide leak out through the resonant metamaterial elements, forming a spatially diverse waveform at the scene. As the frequency is scanned, the waveforms change, such that scene information can be encoded onto a set of frequency measurements. The compressive nature of the metamaterial imager enables image reconstruction from a significantly reduced number of measurements. We characterize the resolution of this complex aperture by studying the simulated point spread function (PSF) computed using different image reconstruction techniques. We compare the imaging performance of the system with that expected from synthetic aperture radar (SAR) limits. © 2015, Electromagnetics Academy. All rights reserved.
News Article | December 19, 2014
Microsoft’s co-founders are backing a Seattle-area startup that wants to apply proprietary metamaterials technology to radar. Bill Gates is co-leader with Madrona Venture Group of a $15 million Series A funding round for Echodyne, which will seek to commercialize the metamaterials technology portfolio of Intellectual Ventures “for a wide range of new radar applications,” Gates says in a news release. Vulcan Capital, the investment vehicle of Microsoft’s other co-founder, Paul Allen, is joining the investment, along with other investors including Lux Capital and The Kresge Foundation. Intellectual Ventures (IV), the controversial patent holding and invention shop co-founded by former Microsoft chief technology officer Nathan Myhrvold, has now spawned three companies focused on different applications of metamaterials—artificial materials often assembled in patterns and with structures engineered to have specific effects on light, sound, radio, or other waves. Gates and Lux Capital are also among the investors in Kymeta, the best-known IV spinout in the field, which is applying metamaterials to satellite antennas. The Redmond, WA, company earlier this week announced a $20 million funding round, on top of $62 million it had raised since spinning out of IV in 2012. It also installed co-founder and CTO Nathan Kundtz as interim CEO as it looks for a permanent replacement for Vern Fotheringham, who is stepping down at the end of the year. Meanwhile, Evolv Technologies, based in Boston, is applying related technology to advanced imaging, and last year raised $11.8 million. The latest spinout, Echodyne, is co-founded by Eben Frankenberg and Tom Driscoll, who had senior leadership roles at IV. Frankenberg, Echodyne’s CEO, was previously in charge of IV’s efforts to spin out companies and was its chief operating officer. Driscoll, who is CTO, directed IV’s Metamaterials Commercialization Center—described as “a team of engineers, physicists, and scientists dedicated to furthering the development and commercial readiness of our metamaterials inventions.” Driscoll also researched metamaterials at Duke University and University of California, San Diego, with which IV has collaborated on the technology. Metamaterials promise “electronically scanned radar systems that are less expensive, smaller, thinner, lighter, and less power-hungry than existing devices,” according to a description from the Metamaterials Commercialization Center, which shows a picture of unmanned drone aircraft and a passenger car on the road. [Editor’s note: Shortly after Xconomy posted this story, the page from which this description was taken—http://www.metamaterialscenter.com/applications/radar-systems— was removed.] “Radar is a pervasive technology that touches almost all aspects of society today, including civil, defense, commercial, and consumer applications,” the description continues. “Radar is essential to weather forecasting, aviation, maritime navigation, and national defense. Within the next decade, radar will be integral to autonomous vehicles, which promise to dramatically reduce the number of traffic accidents and fatalities.” “I’m very excited about the market potential for our breakthrough metamaterials-based radars,” Frankenberg says in the news release. “They stand to be disruptive to existing radar markets, but also enabling for whole new categories of radars never before contemplated or thought possible.” Bellevue, WA-based Echodyne, not surprisingly, isn’t saying much more about its specific strategy, making a pun about this stealthy, under-the-radar startup irresistible. Suffice it to say that Seattle’s richest and most successful technology entrepreneurs have decided to bet big on this technology, and to place those bets on companies based locally. Benjamin Romano is editor of Xconomy Seattle. Email him at bromano [at] xconomy.com. Follow @bromano
News Article | March 17, 2015
Echodyne, a secretive Seattle-area startup company backed by investors including Bill Gates and Paul Allen, is developing a novel, high-performance radar suitable for drones, robots, and self-driving cars. The technology could potentially allow such vehicles to operate independently in a range of conditions. The company, housed in a drab, unmarked building just off State Route 520 in Bellevue, WA, thinks it can dramatically improve upon current radar systems in terms of cost, size, weight, and performance, by using metamaterials, which Echodyne co-founder and chief technology officer Tom Driscoll describes as “sub-wave length geometric configurations of metal and circuit board.” (We’ll dive into that in a minute—for now, think tiny structures that can change the way a surface interacts with radio waves.) Echodyne will be marketing its technology to government and military customers, the traditional behemoths of the radar industry. But its co-founders are more excited about building a commercial business serving new markets and applications that haven’t used radar before because it was too expensive, too heavy, or didn’t offer a meaningful improvement over existing optical sensing technologies. “We have this concept of radar vision, where you’re actually using radar as a vision system for autonomous and unmanned vehicles as opposed to an exotic military-grade only sensor,” says co-founder and CEO Eben Frankenberg. Echodyne is the most recent metamaterials company to spin out of Intellectual Ventures, the patent licensing and invention business co-founded by former Microsoft chief technology officer Nathan Myhrvold. Intellectual Ventures amassed a significant metamaterials intellectual property portfolio and further developed the technology through its Metamaterials Commercialization Center, which Driscoll directed. The other companies are Kymeta, which has raised $82 million to apply metamaterials technology to satellite communications (and Monday announced a partnership with Airbus Defense and Space focused on the maritime industry), and Evolv Technology, based in Boston and funded to the tune of $12 million to tackle advanced imaging. Last December, Echodyne announced $15 million in funding from Gates, Madrona Venture Group, Allen’s Vulcan Capital, Lux Capital, and The Kresge Foundation. “There’s a perception that because [neither] Kymeta, nor Evolv, nor us have launched any true product yet, that all of metamaterials is being squirreled away in some military domain and no one will ever see it,” Driscoll says. “It’s not our intent. We will be partnering with military. We will also be making commercial products.” To demonstrate this, Echodyne installed a prototype metamaterials radar antenna—which looks like a stack of printed circuit boards, about the size of a shoebox top—on an off-the-shelf quad copter. It’s capable of lifting a little more than six pounds, though the prototype unit weighs only about 2.6 pounds. The company modified the flight controls so that the drone could autonomously follow a target, using the radar antenna to guide it. Frankenberg and Driscoll say the drone—which they showed off on a conference table, but did not allow me to photograph—followed them around a field. “We gave a tiny quad copter the ability to see and image the world around it with radar,” Driscoll says, calling it a first for a radar system capable of scanning for new objects while tracking existing ones—capabilities previously confined to high-end electronically scanning radars. “You couldn’t even lift anybody else’s electronically scanning radar with this [quad copter] at almost any price,” Frankenberg says. To explain why Echodyne believes it can upend the status quo, Frankenberg and Driscoll laid out the limitations of current radar technologies—and the advantages of metamaterials. Radar, an acronym dating from the 1940s for radio detection and ranging, was demonstrated in rudimentary form at the beginning of the last century. It works by sending out a pulse of radio waves, which bounce off objects in the way. By measuring how long it takes the radar signal to return to the radar antenna, you can determine the presence and position of distant objects. In the familiar mechanically scanned radars, a single beam is transmitted from a rotating antenna to detect objects in a wide area. That’s the main technology available for commercial applications today, Frankenberg says. Entry-level models for boats cost in the low thousands of dollars. More modern radars direct the beam using phase shifters at each antenna element to create a radio wave front that travels in a desired direction. Frankenberg says the state of the art today is the active electronically scanned array, in which many individual antenna elements work in concert, allowing the radar beam to be pointed almost instantly in any direction—and to switch quickly between scanning for new objects and tracking existing targets. These high-performance systems start at $100,000 and go up into the millions of dollars each, he says. Mechanical radars can only do so much, while electronically scanned arrays remain expensive because of the phase-shifters and amplifiers placed at each antenna element. “The only way to drive the price down is to somehow make the electronics behind every one of those antenna elements cheaper, through volume, but there was no physics change whatsoever,” Frankenberg says. Here’s Echodyne’s big advance: “With our metamaterials approach,” he says, “we fundamentally change the physics of the way the antenna works. That allows us to make a huge improvement in cost, size, weight, and power.” That improvement, Echodyne believes, will … Next Page » Benjamin Romano is editor of Xconomy Seattle. Email him at bromano [at] xconomy.com. Follow @bromano
Machado M.,Metamaterials Commercialization Center |
Ebadi S.,Metamaterials Commercialization Center |
Driscoll T.,Metamaterials Commercialization Center |
Smith D.,Metamaterials Commercialization Center |
Smith D.,Integrated Plasmonics
IEEE MTT-S International Microwave Symposium Digest | Year: 2014
This paper presents an experimental study analyzing the effects of surface treated Polyimide (PI) on dielectric anisotropy and response time of Liquid Crystal (LC) in an In-Plane Switching (IPS) cell design. A Co-Planar Waveguide (CPW) transmission line is used as an in-plane interrogation architecture, with a layer of LC enclosed on top of the CPW. By applying different surface preparations of PI, we are able to derive an optimum condition to maximize birefringence and minimize response times at 20GHz. Measured phase change is increased from 28 deg to 72 deg for the same length of the CPW line. At the same time, measurement results show that fall time is decreased from 9.32s down to 4.1s. These improvements will facilitate realization of LC in microwave devices in need of fast and tunable materials. © 2014 IEEE.