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