On Jan 29, 5:14*pm, Roy Lewallen wrote:
Roger wrote:
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.

Fact or Fiction?

Fiction.

Efficient antennas can be made which are much shorter than a half
wavelength. They'll be narrowband and highly reactive, however. What do
the scientists say about the bandwidth and feedpoint impedance? Where
can we find published data?

Sounds to me like somebody is trying to sell some stock.

Roy Lewallen, W7EL

Roy,

Here is a paper describing the feedpoint impedance and how they
counteract the capacitive reactance without the typical matching
network.

http://www.ece.arizona.edu/~ziolkows..._July_2006.pdf

A number of other papers on these antennas are located he

http://www.ece.arizona.edu/~ziolkows...0Antennas.html

I look forward to your feedback and the comments by others on this
subject,

Roger

On Fri, 29 Jan 2010 21:24:47 -0800 (PST), Roger
wrote:

Here is a paper describing the feedpoint impedance and how they
counteract the capacitive reactance without the typical matching
network.

http://www.ece.arizona.edu/~ziolkows..._July_2006.pdf

Not much original work there - It had been kicking around for years
prior to publication. Boeing Skunk Works stuff I posted here at least
10 years ago when it was more interestingly portrayed as negative
refraction elements.

A number of other papers on these antennas are located he

http://www.ece.arizona.edu/~ziolkows...0Antennas.html

a bibliography.... So what?

73's
Richard Clark, KB7QHC

Roger wrote:

Roy,

Here is a paper describing the feedpoint impedance and how they
counteract the capacitive reactance without the typical matching
network.

http://www.ece.arizona.edu/~ziolkows..._July_2006.pdf

A number of other papers on these antennas are located he

http://www.ece.arizona.edu/~ziolkows...0Antennas.html

I look forward to your feedback and the comments by others on this
subject,

Roger

Thanks very much for the additional information. It's very good news
indeed, and the first I've heard of anyone being able to do this. My
so-far 100% reliable antenna rule of "Small-Broadband-Efficient: Choose
Any Two" might finally be broken. My "fiction" judgment was based on the
initial description which sounded so much like so many I've heard over
the years. I amend it to "Sure looks promising", since it looks like
they've finally really attacked one of the fundamental limitations in a
way that might bear fruit. A career in electronic equipment product
development has taught me that there's a vast distance between getting
something to work once in a lab and building them by the thousands out
of real parts and having them all work as specified. The path between is
full of surprises and obstacles, most of which can be overcome but
sometimes some which simply can't. I sure hope this can be developed to
the point of practicality. An encouraging factor is that there's a real
market for efficient, electrically small antennas in things like RFID
tags and keychain remote control units, to name just a couple. This
means that money will be available for development.

Roy Lewallen, W7EL