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Army Researchers Focus on Smart,
Stealthy Antennas at last??

February 16, 2010 - by Henry S. Kenyon

If U.S. Army scientists have their way, future antennas for vehicles and dismounted infantry will be smaller and more nondescript and will
feature greatly increased reception. Research is focusing on lightweight conformal antennas that can be built into soldiers uniforms and
equipment as well as vehicle structures.
One of the major thrusts of the Armys work is making antennas less obvious, says Dr. Steven Weiss, team leader of the U.S. Army
Research Laboratorys (ARLs) antenna team. He notes that Army researchers also are examining new technologies such as
metamaterialsengineered substances that do not have properties found in nature. For example, mounting antennas to conform to the
side or the inside of a vehicle can affect their performance, but antennas made of metamaterials may counteract some of these effects.
The Army is interested in developing conformal antennas for ground vehicles. These could be used for communications or jamming
improvised explosive devices. Because they are part of the vehicles structure, they lower its overall visual profile, making it more
survivable on the battlefield. Antennas could be inconspicuously mounted onto vehicles in a number of ways: flush against the vehicles
skin, incorporated into part of its structure such as a bumper, or conformed to the contours of the vehicles shape.
But developing conformal antennas for ground vehicles presents a variety of challenges. These issues include ground effects, such as radio
interference, and size and weight issues for vehicles equipped with the antennas.
Weiss notes that researchers want to develop electronically scannable antennas that do not move physically but would enable radios to
maintain point-to-point communications. Electronically scanned phased antennas are used for radar systems on ships and aircraft, but
their cost prohibits mass installation on ground vehicles, he says.
The Army has a pressing need for antennas that provide data and satellite communications on the move. Weiss cites the ARLs satellite
communications on-the-move effort as an example of the services research goals and challenges. How do you replace a double
gimbaled dish antenna with a phased array that is not a budget buster or requires a refrigeration system to keep the antenna cool? he
asks. Another criteria is the ability to support enough bandwidth to manage multiple communications functions.
In addition, ARL scientists are examining metamaterials for new antenna applications. Weiss cautions that there was a great deal of hype
about metamaterials when their potential was first developed but adds that they can be effective for work on conformal vehicle antennas.
He notes that researchers are interested in one particular type of application known as artificial magnetic conductors (AMCs

I'm surprised at the "at last??" part. Its been going on for years. For example, try a Google for "Comwin antenna". The Comwin antenna project was over 10 years ago and looked at putting HF, VHF, and UHF antennas onto a soldier, but tailored into the soldiers clothing and helmet. Most of the technical reports are no longer freely available on the web, but its an area I was researching myself a few years ago. You can still find brief Comwin reports/presentations via Google.

Low profile vehicle antennas are another area that's seen a lot of research, but the laws of physics will only allow you to do so much if you want high performance (as the users usually do) as well.

With the USA concentrating on their JTRS radio systems there has been a developing need for these sorts of antennas (smart and low profile) over the past several years, and I know that a lot of research has already been done in many countries. Unfortunately, its not an area that I work in any more.

Cheers,

Peter

An HF antenna woven into a tabard was used in the early 70s as part of an experimental underground comms system. The surface antenna was a multiturn loop laid on the ground. I believe this was at about 3MHz.

Also, I have a 100w Pye mobile VHF transceiver that was used by the security services in conjunction with a slot antenna cut into the roof of a vinyl roofed car (remember them?) the install was completely invisible but I feel sorry for anyone sitting inside who had braces on their teeth!!!

Other variations on the stealth/low profile theme have been around for years. Pye used the carrying strap for the Bantam and the PF70 as an antenna for their low band models and rear windscreen heaters have often been used as antennae for both broadcast reception and VHF/UHF comms.

Phil