Here is the journal article:

R.W. Ziolkowski, P. Jin, J.A. Nielsen, M.H. Tanielian and C.L.
Holloway. Design and experimental verification of Z antennas at UHF
frequencies. IEEE Antennas Wireless Propag. Lett., 2009 vol. 8, pp.
1329-1332.

Elektor magazine had a news report on these antennas.

"NIST engineers are working with scientists from the University of
Arizona (Tucson) and Boeing Research & Technology (Seattle, Wash.) to
design antennas incorporating metamaterials — materials engineered
with novel, often microscopic, structures to produce unusual
properties. The new antennas radiate as much as 95 percent of an input
radio signal and yet defy normal design parameters. Standard antennas
need to be at least half the size of the signal wavelength to operate
efficiently; at 300 MHz, for instance, an antenna would need to be
half a meter long. The experimental antennas are as small as one-
fiftieth of a wavelength and could shrink further.

In their latest prototype device,* the research team used a metal wire
antenna printed on a small square of copper measuring less than 65
millimeters on a side. The antenna is wired to a signal source.
Mounted on the back of the square is a “Z element” that acts as a
metamaterial — a Z-shaped strip of copper with an inductor (a device
that stores energy magnetically) in the center (see photo).

“The purpose of an antenna is to launch energy into free space,”
explains NIST engineer Christopher Holloway, “But the problem with
antennas that are very small compared to the wavelength is that most
of the signal just gets reflected back to the source. The metamaterial
makes the antenna behave as if it were much larger than it really is,
because the antenna structure stores energy and re-radiates it.”
Conventional antenna designs, Holloway says, achieve a similar effect
by adding bulky “matching network” components to boost efficiency, but
the metamaterial system can be made much smaller. Even more
intriguing, Holloway says, “these metamaterials are much more
‘frequency agile.’ It’s possible we could tune them to work at any
frequency we want, on the fly,” to a degree not possible with
conventional designs.

The Z antennas were designed at the University of Arizona and
fabricated and partially measured at Boeing Research & Technology. The
power efficiency measurements were carried out at NIST laboratories in
Boulder, Colo. The ongoing research is sponsored by the Defense
Advanced Research Projects Agency.

* R.W. Ziolkowski, P. Jin, J.A. Nielsen, M.H. Tanielian and C.L.
Holloway. Design and experimental verification of Z antennas at UHF
frequencies. IEEE Antennas Wireless Propag. Lett., 2009 vol. 8, pp.
1329-1332.

NIST has an article on these antennas and a photo of a prototype.

http://www.nist.gov/public_affairs/techbeat/current.htm

On Fri, 29 Jan 2010 18:02:03 -0800 (PST), Roger
wrote:

NIST has an article on these antennas and a photo of a prototype.

http://www.nist.gov/public_affairs/techbeat/current.htm

Yeah, yeah, yeah. Now, for the true test of comprehension, answer
this:
What is THE metamaterial?
(cut and paste in response is not an answer, in your own words please,
as YOU understand it)

For extra credit:
What IS metamaterial?
(cut and paste in response is not an answer, in your own words please,
as YOU understand it)

If this cannot be sensibly answered from the accumulation of you
reading of all links and bibliographies offered, then not much is
being offered up in the way of discussion.

73's
Richard Clark, KB7QHC

On 1/29/2010 10:46 PM, Richard Clark wrote:

...
What is THE metamaterial?
(cut and paste in response is not an answer, in your own words please,
as YOU understand it)

For extra credit:
What IS metamaterial?
(cut and paste in response is not an answer, in your own words please,
as YOU understand it)
...
73's
Richard Clark, KB7QHC

The materials used are very similar, in many cases exact, to the
materials used in TTD's (Temporal Tremor Detectors.)

Regards,
JS

Hmmm, I'm thinking it could be useful as an element for a frequency agile
radar array. Diversity radar?
If current radar detection systems rely on the target detecting an incoming
beam at a given pulse rate and frequency, then by varying the frequency and
pulse rate constantly, detection would be more difficult.
Computer hardware and software is sufficiently powerful to be capable of
processing the target returns at varying frequencies and GPS satellites can
provide a frequency locked source for synchronising the transmitter and
receiver, so you end up with effectively a stealth active radar system.
A wide band electrically tuned antenna would be essential for such an
application. It might even be able to detect stealthy aircraft and ships as
they tend to be optimized to absorb/divert frequencies in the most used
radar bands.
An electrically controlled frequency agile antenna which forms part of an
electrically steerable planar system would also be useful for jamming
multiple frequencies and sources. This could turn out to be a somewhat
expensive project.

Mike G0ULI

"Roger" wrote in message
...
NIST has an article on these antennas and a photo of a prototype.

http://www.nist.gov/public_affairs/techbeat/current.htm

On Fri, 29 Jan 2010 17:57:08 -0800 (PST), Roger
wrote:

The experimental antennas are as small as one-
fiftieth of a wavelength and could shrink further.

In fact, commercial Ham antennas with similar efficiencies at similar
scales have been around for decades.

Shrinking them further encounters loss accumulating at the 4th power
of size. This is a very difficult proposition to beat in stale
reporting with the concurrent lack of proven models following after
lo' these 4 years. That is pretty sound evidence of these researchers
having been lost beyond the precipice of an astronomical plunge in
efficiency.

73's
Richard Clark, KB7QHC

On Jan 29, 7:57*pm, Roger wrote:
The metamaterial
makes the antenna behave as if it were much larger than it really is,
because the antenna structure stores energy and re-radiates it.”
Conventional antenna designs, Holloway says, achieve a similar effect
by adding bulky “matching network” components to boost efficiency, but
the metamaterial system can be made much smaller.

So far nothing has been written about the radiation resistance of this
"1/50-wave" antenna.

Even if the design eliminates the feedpoint Xc of this electrically
small radiator at the operating frequency, its radiation resistance
could be expected to be miniscule, because the Rr of a radiator
depends on the electrical wavelengths it exposes to space.

The claim that it radiates 95% of the power applied to it may be true,
but needs to evaluated with the radiator as part of an r-f system --
where with very low Rr, much of the available power can be subject to
very high losses before it reaches the radiator.

RF

On Jan 30, 5:43*am, Richard Fry wrote:
Even if the design eliminates the feedpoint Xc of this electrically
small radiator at the operating frequency, its radiation resistance
could be expected to be miniscule, because the Rr of a radiator
depends on the electrical wavelengths it exposes to space.

What if a metamaterial conductor were discovered with a natural
VF=0.1? In the lab, light has been slowed down to a crawl.
--
73, Cecil, w5dxp.com