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Showing posts with label military applications. Show all posts
Showing posts with label military applications. Show all posts
Researchers at a university in North China's Tianjin Municipality made a breakthrough in holography based on optical metasurfaces, with an expert saying the technology could improve the accuracy of military reconnaissance.
A research team from the Center for Terahertz Waves of Tianjin University has greatly advanced holographic imaging technology and realized reflective chiral holography for the first time, Science and Technology Daily reported on Wednesday.
"Using the metasurfaces material and terahertz waves, the updated holographic plate could exhibit an image with essential features and very accurate status of location, which would greatly improve military reconnaissance," Song Zhongping, a military expert, told the Global Times on Thursday.
Holographic plates with metasurfaces could also record more data and better reproduce the images than ordinary plates, Song added.
A terahertz wave is a kind of electromagnetic wave, which has strong penetrability with good directionality. The waves are safe for humans. They are currently the least understood and least developed electromagnetic spectral band, according to the report.
The metasurfaces plate can recognize different polarization states of light. This enables it to store more information and make fully independent holographic imaging, the newspaper reported.
"Such holography technology must pass various engineering tests under a battlefield environment to confirm its functioning before it is eventually adopted by the People's Liberation Army (PLA)," Song noted.
If fully developed, the technology would bring a sharp advance for artillery units of the PLA, allowing the units to achieve global leadership in artillery technology, Song said.
The ability to convert a good idea into combat capability as soon as possible is important to the PLA, as it also would allow units to have a quick reaction in future battles, Song added.
Terahertz radar technology has shown promise in the healthcare imaging domain, yet its employment for military applications may still be some years away. (Photo: HU)
MILITARY TECHNOLOGY’s forthcoming ‘Facts and Fallacies’ article examines recent technological advances which claim to ease the detection of so-called ‘stealth’ aircraft; those possessing a low Radar Cross Section (RCS).
One particular technology falling under our spotlight is Terahertz radar. Put simply, Terahertz (THz) radar transmits photons. These photons have exceptionally short wavelengths of between 0.3THz to three terahertz. These photons can penetrate non-metallic materials and see inside an object in a similar fashion to an X-ray. The logic for its use in radar is to penetrate the non-metallic skins used by fighters such as the Lockheed Martin F-22A RAPTOR and F-35A/B/C LIGHTNING II, and Dassault’s RAFALE F3B/C/M and discern objects inside the aircraft, hence betraying its presence and position.
In September 2017, reports emerged that the China North Industries Group Corporation (CNIGC) had tested a radar capable of transmitting terahertz radiation using technology developed by China Academy of Engineering Physics (CEAP). The report explained that the firm had developed a Terahertz radar boasting, “unprecedented power levels.”
Such power levels would be necessary if the radar was to be capable of detecting an aircraft at a tactically useful range (see below). One CNIGC executive stated that the skins used in the construction of the F-35A/B/C, “will look at thin and transparent as stockings,” to a such a radar. Reports continued that CEAP is working to reduce the radar’s physical size, and increase its power to develop a militarily practical system.
DEBUNKING THE CLAIMS
Could China’s boasts regarding Terahertz radar be true, or are they mere hyperbole? We caught up with Dr Iain Scott, radar capability manager at Leonardo’s airborne and space systems division. Dr Scott was awarded the Royal Academy of Engineering’s Silver Medal in late June for his contribution to Leonardo’s VIXEN-E combat aircraft radar, and is a leading authority on military radar technology. Leonardo is sceptical of the Chinese claims, Dr Scott noted, adding that, “in the past (the company) has looked at the use of the Terahertz band (and) the most promising opportunity was a successful demonstration by Leonardo of a Terahertz imaging solution to identify buried objects.”
China announced the creation of radar that can detect aircraft "invisible." (Photo: HU)
The problem, Dr Scott continued, was generating the required power and developing suitably sensitive receivers which could enable Terahertz radar to be used for military applications: “To field a military solution in the next five years would rely on technology that is mature and available today. The most recent press reports quoting Chinese researchers describe the technology as still having a long way to go, and being too bulky and not viable for fitting to a plane or satellite.”
One of the challenges of realising a militarily useful Terahertz radar is power consumption. In order to detect flying targets at a useful range, any Terahertz radar would consume significant quantities of electricity, Dr Scott stated. This is because the aircraft carrying the radar would need to be out of the reach of long-range Air-to-Air and Surface-to-Air Missiles (AAM/SAM). As a means of comparison, the Russian Vympel R-27EA Semi-Active Radar Homing (SARH)/Active Radar Homing (ARH) and infrared-guided AAM has a published range in excess of 70.2 nautical miles/nm (130 kilometres/km).
Meanwhile, the 40N6 SARH/ARH SAM used by Russia’s Almaz-Antey S-400 SAM battery may have a range of 216nm (400 kilometres). As a ball park figure most combat aircraft have radars capable to detecting targets at circa 100nm (185km) range. However, these jets are single, or twin-engined which limits the electrical power they would be able to generate for a Terahertz radar. One option could be to place such a radar on a large multi-engined platform such as a Boeing KC-135 series tanker. Yet this also brings challenges.
Dr Scott states: “The issue is that these large platforms are not stealthy and with the increasing range of integrated air defence systems, they are required to stand-off many hundreds of kilometres from the threat area. This then requires even more radiated power. A further complication is that power not converted into radiated energy must be dissipated somewhere, usually into a liquid cooling system. This represents another significant challenge to an airborne solution.”
In addition to the technical challenges the atmosphere creates problems. The Earth’s atmosphere contains moisture and this has a habit of absorbing electronic particles. As a general rule of thumb, the higher the frequency of the radar, the more of a radar’s transmission is absorbed by this moisture. This reduces the radar’s range and potentially degrades its ability to see targets in detail. This is a serious challenge given the high frequencies used by Terahertz radar: “Even if the power and sensitivity problems could be overcome, the atmospheric attenuation in the Terahertz band is so great that the detection range is likely to be so short as to be militarily ineffective.”
One potential solution could be to use a Terahertz radar as a ground-based air surveillance radar, as this would remove some of the challenges regarding available power because the radar could have a power source capable of generating the required electricity positioned nearby without the space constraints inherent in an aircraft.
Nevertheless, Dr Scott notes that on the ground the range of a radar tends to be limited to the distance that its antenna can ‘see.’ Like a person, a radar can see as far as the horizon. Place the radar’s antenna on a tower, on high ground or angle it towards the sky and it can see further. Nonetheless, “the traditional radar horizon limitation of a ground-based radar would allow a stealth platform to penetrate a very long way before being detected,” obviating the potential advantage offered by a Terahertz radar.
In both ground and airborne configurations, Dr Scott states that Terahertz radar offers some potential benefits in terms of its ability to see a target in detail. Generally speaking the higher a radar’s transmission frequency, the sharper the detail of the target. However X-band (8.5-10.68GHz) radars already provide sharp target resolution. This is particularly important when using such a radar for fire control to achieve a kill, and hence why many combat aircraft radars transmit in X-band, along with ground-based and naval fire control radars.
The problem is that fire control radars must to detect a target at range to allow a weapon to be released as soon as possible, Dr Scott remarks, and hence we are back to the quandary of Terahertz radar and range: “The question is, given the levels of atmospheric attenuation, whether Terahertz radar will ever provide a realistic military solution, or if other approaches might provide a more plausible and shorter-term means to detect low RCS aircraft. Given the fundamental challenges outlined above (generating meaningful power levels and efficiency) it is unrealistic to think that any airborne military system would be fielded in the next ten to 15 years.”
China North Industries
Group Corporation tested a device capable of generating terahertz radiation
with unprecedented power at a military research facility in Chengdu, Sichuan
province, last week, Science and Technology Daily reported
on Monday.
Terahertz radiation,
or T-rays, can penetrate composite materials to reach underlying metallic
layers and is widely used in industrial plants to spot product defects.
Terahertz radars are
already capable of finding a concealed weapon in a crowd from hundreds of
metres away, and a more powerful version is under development to put on an
early warning aircraft or satellite to identify and track military aircraft,
including the US’
F-22 and F-35 stealth fighters.
Attempts to realise
military applications for T-ray technology have been limited by the bulk and
low power output of terahertz generators. The rays fall on the spectrum between
microwaves and light and cannot be produced by conventional radio or optical
devices.
The report said the
new device could generate stable, continuous radiation at an average level up
to 18 watts, and terahertz pulses with peak power close to one megawatt, on par
with some military radars.
A technical executive
at a vendor in China
for T-ray devices used in F-35 manufacturing said the reported power levels of
the device were “more than a million times higher than the power of the T-ray
device used to measure the thickness of coatings on the F-35”.
“The radar-absorbent
coatings on the F-35 will look as thin and transparent as stockings if [the
Chinese instrument] is as powerful as they claim,” the executive said.
The end of stealth?
New Chinese radar capable of detecting ‘invisible’ targets 100km away
“It looks like they
will soon be able to have an echo image of the F-35 with some high-definition
details ... from a respectable distance.”
China has claimed that
some of its existing very-high-frequency military radar can detect traces of
stealth aircraft but doubters say the microwaves from those devices would be
absorbed or deflected by stealth materials.
Qi Jiaran, deputy
director of the department of microwave engineering at the Harbin Institute of
Technology, said the new instrument could be a game changer.
Qi, a terahertz
imaging specialist not directly involved in the Chengdu
project, said the report suggested that China had made a breakthrough in
some key technology and components.
But the technology was
still bulky and could not be fitted easily on a plane or satellite.
“Field deployment may
require power output at the kilowatt level. There is still a long way to go
before we can monitor stealth fighters or bombers from space,” Qi said.
The new instrument was
developed by the China Academy of Engineering Physics in Mianyang, the nation’s
largest research institute for the development and production of nuclear
weapons.
According to the
academy’s website, efforts were under way to increase the device’s power output
and shrink its size for military applications.
Providing timely information through high data rate communications enhances the situational awareness of military units engaged in combat and can be vital to their safety and the success of their mission. Such high data rate communications systems require amplifiers with broad bandwidth and high power, which can be delivered by the compact helical traveling wave tubes (TWT), under development at Teraphysics Corporation of Cleveland, Ohio.
Cleveland, OH (PRWEB) May 29, 2014
Providing timely information through high data rate communications enhances the situational awareness of military units engaged in combat and can be vital to their safety and the success of their mission. Such high data rate communications systems require amplifiers with broad bandwidth and high power, which can be delivered by the compact helical traveling wave tubes (TWT), under development at Teraphysics Corporation of Cleveland, Ohio.
On May 14, 2014, Teraphysics was awarded a Phase I Small Business Innovative Research contract from the Air Force Research Laboratory at Wright Patterson Air Force Base in Dayton, Ohio to develop a 100 Watt TWT amplifier operating over the 5 GHz of contiguous bandwidth from 71 to 76 GHz in the region of the electromagnetic spectrum, known as E-Band.
The Teraphysics amplifier achieves the demanding requirements of the Air Force by utilizing computer design techniques originated by the contract Principal Investigator, Dr. Carol Kory, Teraphysics Vice President for Technology Development, and by adopting microfabrication technology originally developed for other applications. The Teraphysics TWT achieves very wide bandwidth by using a helical slow wave circuit consisting of a miniature coil of gold wire supported by a thin diamond sheet. The result is an amplifier with nearly constant gain over the 5 GHz bandwidth. The Teraphysics TWT has the length and width of a credit card and weighs only one pound, approximately one tenth the size of a conventional device.
Teraphysics has previously developed helical devices for operation at 650 and 94 GHz. The development of the Teraphysics miniature helical TWT had previously been supported by contracts with NASA Jet Propulsion Laboratory (JPL), the Defense Advanced Research Projects Agency (DARPA), the Army Research Office (ARO), and the Air Force Office of Scientific Research (AFOSR). In addition to the military applications, the compact Teraphysics TWT is expected to have significant impact on satellite communications, communication links for unpiloted aircraft (drones), and in the backhaul of accumulated signals of wireless handheld devices to the main fiber optic telecommunications network.
To speak with Dr. James A. Dayton, Jr., Chief Technology Officer of Teraphysics, or for more technical information, please contact Christian Hunter, APR, christian(at)studiothink(dot)net.
About Teraphysics Corporation:
Located in Northeast Ohio, Teraphysics develops powerful, efficient and compact devices that operate in the millimeter and sub-millimeter (terahertz) frequency bands. The organization holds multiple patents for intellectual property used in the micro fabrication of devices designed to lead to revolutionary application and commercialization of millimeter-wave and terahertz technology. For more information on Teraphysics, visit teraphysics.com.
Read more at http://www.redorbit.com/news/science/1113157868/air-force-awards-teraphysics-corporation-contract-for-eband-communications-amplifier/#XjGIkemYSdLRKgZJ.99
