~e; invisible antenna design

[bc <human@electronetwork.org>]

  [antenna design has been a curiousity ever since seeing an
  early manual on the old metal TV antennas were all about
  the place, pre-cable TV era. the materials and geometry
  were the reason for the aesthetic design of the antenna,
  directly correlating with how to maximize picking-up the
  radio and tv signals from the aether. in the past year or
  two there have been some advances in this regard. one
  was a military one, if remembering correctly, that could
  be sprayed onto a tarp or tent or car window in a certain
  pattern and be used as a ultra-thin, almost paint-based it
  seemed, antenna. that was that. the other clue that things
  may be changing due to materials is the article below, and
  news about plastics being able to do some things that have
  been done with metals previously. thus, the geometries of
  metal that made the skeleton-like antennas often seen ontop
  of roofs, now because of a change in material may also have
  a change in form. one guess is that these may be reception
  antennae, not transmitters. but then again, if in a cell-phone
  these newer antennas must have some formal shape that is
  capable of sending a directed signal. one downside, and this
  is all speculation of course, is that issues with the older
  cellphone antennas which dealt with the cancer-debate issue
  would seem to be tougher if the antenna was now in the phone
  itself, not above the phone (near scalp) but instead by human
  cheekbones and whatnot. with electromagnetic radiation there.
  but it is to be debated, but for some reason, the 'invisibility'
  of the antenna is somewhat scary, as it can make these things,
  these devices, even more mysterious in their workings, and
  more of a black-box/magical device. so that one cannot 'see'
  that it may have more complex effects than plastic phones
  and their hi-techno designs might suggest via industrial styling.]

 

March 7, 2002	WHAT'S NEXT

Shrinking and Rethinking the Old Vertical Antenna

By DAVID F. GALLAGHER
  http://www.nytimes.com/2002/03/07/technology/circuits/07NEXT.html

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technology news and tips and exclusive commentary by David Pogue, the 
State of the Art columnist.

As cellphones start to approach the size of matchboxes, their 
antennas are shrinking, too. In the tiniest new phones the antenna is 
often hidden inside, where it may take the form of a piece of foil or 
a coiled wire. But a new material may allow antennas for phones and 
other devices to become both obvious and invisible at the same time.

The material was invented by Tom A. Aisenbrey, general manager at 
Integral Technologies (news/quote), a tiny company with offices in 
Bellingham, Wash., and Vancouver, British Columbia. While working on 
a more traditional antenna, he stumbled across a way to mix a 
metallic compound with plastic or rubber to make a conductive 
material that can be molded into any shape. That makes it possible to 
create phones in which the plastic case serves as the antenna.

Because the material is such an effective conductor, it reduces the 
amount of battery power needed to send a signal and offers better 
reception than a traditional antenna, Integral says.

Mr. Aisenbrey has been trying out prototype antennas on his own 
cellphone for months. He said that the antenna he is now using is a 
careful blend of silicone and his metallic compound, the ingredients 
of which are a company secret. The silicone casing makes a good shock 
absorber if the phone is dropped, he said, and the antenna can pull 
in a signal even in deep valleys where reception may ordinarily be 
poor. Integral says that the manufacturing costs of the new antennas 
will be the same as or less than those of traditional metal ones.

Lothar Schmidt, a technical manager at Cetecom, a company that was 
hired by Integral to assess the antenna, said tests had shown that in 
some cases the new antenna more than doubled a cellphone's outgoing 
signal strength.

Integral is working with GE Plastics to help it develop and market 
the material, and the two companies are talking to several cellphone 
makers about using it in their products, said William Robinson, 
Integral's chief executive.

Of course, there are other gadgets that could benefit from better 
antennas, like those that make use of the short-range wireless 
standard Bluetooth and the Global Positioning System, the satellite 
network that allows users to plot precise locations. Integral is even 
talking to a provider of satellite tracking services about turning 
truck bumpers into giant antennas by making them out of a rubbery 
blend of the new material. The antennas would improve communication 
with low-orbit satellites that allow the company to report the 
location of a truck and status information back to its clients.

The bumpers will need some exposure to the open sky to communicate 
with the satellites. But unlike a cellphone network, the tracking 
system does not need to remain in constant contact to do its job, so 
it is not a crisis if the signal is temporarily blocked by tunnels or 
buildings.

Mr. Robinson said that Integral also planned to make flat antenna 
strips that could be attached to the sides of shipping containers so 
that they could be tracked the same way. The strips will be an 
improvement over standard metal antennas, which are often targets for 
vandals or are accidentally broken off, he said.

Mr. Aisenbrey said that the same principle could be applied to cars, 
where "you could turn the gasket of your windshield into an antenna." 
Or manufacturers could build an antenna into the surface of a boat's 
deck.

The United States military has taken a similar approach by building 
metal antennas into the structural frame of airplanes. SkyCross, a 
company based in Melbourne, Fla., that has developed commercial 
applications for some military communications technology, is working 
to apply the concept to cars and perhaps buildings.

When the antenna is structurally embedded in a car, it becomes "a 
very effective radiator" of electromagnetic waves, said Alan L. 
Haase, chief executive of Skycross. An antenna built into the walls 
of a building could do the same thing, he said.

Skycross is also looking at technology that would allow it to "print" 
an antenna on the inside of a cellphone's case, Mr. Haase said.

Integral's invention shows that plastic, hardly a cutting-edge 
material, still has plenty of untapped high-tech potential.

Researchers have devoted much attention lately to conductive 
plastics, which, unlike Integral's material, do not require any metal 
to make them effective carriers of electric current. The technology 
is already being used to create moldable plastic batteries for 
electronic products. For example, NEC released a laptop last year 
with a lithium-polymer battery wrapped around the back of its screen.

Blends of plastic and metal compounds similar to the one in 
Integral's antenna are often found in military equipment, where they 
act as shielding material to keep enemy sensors from spotting sources 
of electromagnetic energy. They can also shield people from energy 
sources in computers and other devices.

Mr. Aisenbrey said that Integral's innovation was to tweak the blend 
to make it conductive enough for use as an antenna - in effect, 
turning a barricade into a pathway.

Experts on antenna design said that Integral's technology sounded 
interesting but that they would need more information to evaluate it. 
They noted that other researchers were also looking to novel 
materials as a way to boost antenna performance.

Dr. David M. Pozar, professor of electrical and computer engineering 
at the University of Massachusetts and a researcher in the school's 
Antenna Laboratory, questioned Integral's emphasis on seeking to 
patent its technology.

"Patents in the antenna area, by themselves, do not ensure the 
success of a product, and it is usually very easy to circumvent 
patents" in this field, Dr. Pozar said. Performance and price rather 
than patents are the keys to success, he added.

NYTimes online copyright 2002. {~e.org fair-use, 2oo2}

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