radar – Baza de Date

Inginerii dezvoltă o piele flexibilă care captează undele radar, obiecte de mantale(Engineers develop flexible skin that traps radar waves, cloaks objects

au dezvoltat o nouă meta-piele flexibilă, extensibilă și adaptabilă, care utilizează rânduri de dispozitive mici, lichide și metalice pentru a acoperi un obiect din ochii ascuțiți ai radarului.
Meta-pielea ia numele din metamateriale, care sunt compozite care au proprietăți care nu sunt găsite în natură și care pot manipula undele electromagnetice. Prin întinderea și flexarea meta-pielei polimerului, aceasta poate fi reglată pentru a reduce reflexia unei game largi de frecvențe radar.

Posted: Mar 07, 2016
Engineers develop flexible skin that traps radar waves, cloaks objects (Nanowerk News) Iowa State University engineers have developed a new flexible, stretchable and tunable „meta-skin” that uses rows of small, liquid-metal devices to cloak an object from the sharp eyes of radar.
The meta-skin takes its name from metamaterials, which are composites that have properties not found in nature and that can manipulate electromagnetic waves. By stretching and flexing the polymer meta-skin, it can be tuned to reduce the reflection of a wide range of radar frequencies.
The journal Scientific Reports recently reported the discovery online („From Flexible and Stretchable Meta-Atom to Metamaterial: A Wearable Microwave Meta-Skin with Tunable Frequency Selective and Cloaking Effects”). Lead authors from Iowa State’s department of electrical and computer engineering are Liang Dong, associate professor; and Jiming Song, professor. Co-authors are Iowa State graduate students Siming Yang, Peng Liu and Qiugu Wang; and former Iowa State undergraduate Mingda Yang. The National Science Foundation and the China Scholarship Council have partially supported the project.

This flexible, stretchable and tunable „meta-skin” can trap radar waves and cloak objects from detection. (Image: Liang Dong/Iowa State University)
„It is believed that the present meta-skin technology will find many applications in electromagnetic frequency tuning, shielding and scattering suppression,” the engineers wrote in their paper.
Dong has a background in fabricating micro and nanoscale devices and working with liquids and polymers; Song has expertise in looking for new applications of electromagnetic waves.
Working together, they were hoping to prove an idea: that electromagnetic waves – perhaps even the shorter wavelengths of visible light – can be suppressed with flexible, tunable liquid-metal technologies.
What they came up with are rows of split ring resonators embedded inside layers of silicone sheets. The electric resonators are filled with galinstan, a metal alloy that’s liquid at room temperature and less toxic than other liquid metals such as mercury.
Those resonators are small rings with an outer radius of 2.5 millimeters and a thickness of half a millimeter. They have a 1 millimeter gap, essentially creating a small, curved segment of liquid wire.
The rings create electric inductors and the gaps create electric capacitors. Together they create a resonator that can trap and suppress radar waves at a certain frequency. Stretching the meta-skin changes the size of the liquid metal rings inside and changes the frequency the devices suppress.
Tests showed radar suppression was about 75 percent in the frequency range of 8 to 10 gigahertz, according to the paper. When objects are wrapped in the meta-skin, the radar waves are suppressed in all incident directions and observation angles.
„Therefore, this meta-skin technology is different from traditional stealth technologies that often only reduce the backscattering, i.e., the power reflected back to a probing radar,” the engineers wrote in their paper.
As he discussed the technology, Song took a tablet computer and called up a picture of the B-2 stealth bomber. One day, he said, the meta-skin could coat the surface of the next generation of stealth aircraft.
But the researchers are hoping for even more – a cloak of invisibility.
„The long-term goal is to shrink the size of these devices,” Dong said. „Then hopefully we can do this with higher-frequency electromagnetic waves such as visible or infrared light. While that would require advanced nanomanufacturing technologies and appropriate structural modifications, we think this study proves the concept of frequency tuning and broadening, and multidirectional wave suppression with skin-type metamaterials.”

Source: Iowa State University

Read more: Engineers develop flexible skin that traps radar waves, cloaks objects

Respectarea cerințelor de performanță crescătoare la frecvențele cu valuri milimetrice

dezvolta funcționalitatea complementară a materialului semiconductor compus (III-V CMOS), care susține atât funcționalitatea analogică, cât și cea digitală în domeniul frecvențelor undei milimetrice. Nivelele III-V vor fi folosite pentru a menține controlul electrostatic, deoarece lungimea porții este redusă pentru nodurile tehnologice viitoare. Secțiunea transversală mică a nanofirelor facilitează în continuare integrarea pe substraturile cu ajutorul nanotehnologie

Posted: Mar 02, 2016
Meeting the increasing performance demands at millimetre-wave frequencies (Nanowerk News) Future radar imaging systems and 5G communication systems will generate improved resolution and provide higher data-transmission rates when operated at higher frequencies, but at the cost of increased power consumption. To reduce power consumption, increase performance, and lower costs, the European project INSIGHT (Integration of III-V Nanowire Semiconductors for Next Generation High Performance CMOS SOC Technologies) is aiming at developing III-V CMOS (complementary metal-oxide-semiconductor) technology. The six partners, including universities, research institutes and one company, are committed to establishing a manufacturable III-V CMOS technology on Si substrates, to reduce costs and to save scarce materials.
The INSIGHT mission is to develop complementary functionality in compound semiconductor material (III-V CMOS), supporting both analogue and digital functionality in the millimetre-wave frequency domain. III-V nanowires will be used to maintain electrostatic control, as the gate length is scaled for future technology nodes. The small nanowire cross-section further facilitates the integration onto Si substrates using nanotechnology.
“The fabrication of high-performance III-V components on large Si substrates using CMOS compatible technologies opens a path for cost reduction of millimetre-wave key components with minimized usage of critical materials” says Lars-Erik Wernersson, Professor at Lund University and coordinator for INSIGHT. Lund University is coordinating this new European Horizon 2020 research project that has been funded with 4.3 million Euros over 36 months.

Professor Lars-Erik Wernersson from Lund University, introducing the INSIGHT project.
IBM foresees a growing need to push the limits of chip technology to meet the emerging demands of cognitive computers, Internet of Things and Cloud platforms, due to the enormous amount of data they are handling – 90% of which is unstructured. The new technology developed in INSIGHT offers a potential solution to scale chip technology beyond the 10 nm node as well as opening up a range of new application areas. Integrating III-V materials into Si CMOS can enable better logic circuits with a lower power consumption, and in addition can enable the realization of System-on-Chip (SoC) products taking full advantage of III-V’s state-of-the-art RF/Analog metrics.
There is a growing need for performance enhancements of key components in the millimetre-wave frequency range and new consumer applications are demanding low costs. The new technology offers a potential solution, as it may provide both high-performance analogue and digital functionality on the same platform where the improved manufacturability allows production on larger wafers. The INSIGHT consortium addresses the technology need with the ambition to demonstrate circuits and systems by optimizing both material and device properties.
The introduction of III-V materials on silicon substrates by using nanowires is one of the most innovative heterogeneous integration approaches today. Fraunhofer
IAF will bring in their III-V process and circuit design experience, and is interested in transferring the results and findings to next generation III-V device technologies.
The LETI participation in the INSIGHT project involves both the Silicon Component division and the Integrated Circuit & Embedded System division, ranging from materials to the circuit demonstration. The technology expands the LETI platform for smart devices and Internet of Things with the potential to squeeze multiple functions into a single die.
III-V CMOS technology may be particularly suited for millimetre-wave front-ends where it will be used to detect and generate signals for communication, radar and imaging. It is the goal of the INSIGHT consortium to develop key technologies for both the receivers and transmitters, while exploring the limits of the transistor geometry and layout.
Besides Fraunhofer IAF (Germany) and LETI (France), the consortium consists of Lund University (Sweden), University of Glasgow (UK), Tyndall National Institute (Ireland) and IBM (Switzerland). The expertise of the partners spans the complete spectrum from materials, through devices, all the way to circuits and systems, allowing the consortium to take this promising technology further along the path to commercial products. INSIGHT is funded under the Horizon 2020 Programme for Research and Development of the European Union (Grant agreement number 688784).

Source: Project INSIGHT

Read more: Meeting the increasing performance demands at millimetre-wave frequencies