Re: NEC-LIST: Re: Plasma Antennas

At 09:35 AM 5/12/2004 -0700, Jasper van der Graaff wrote:
>Plasma antenna technology looks to be very interesting, with a number of
>advantages over normal antennas. There are also other very interesting
>applications for plasma conductors, such as EM shields (Time Selective
>Surfaces?!). However, at the moment it is unclear for me to see all the
>disadvantages. Ofcourse there is the issue with noise, however Markland
>states that there is very little noise after the gas is ionised and it
>does not have to be problematic for transmit antennas. And there is the
>temperature issue, as remarked by Erik, but presumably also cost, total
>system weight (not of the aerial), reliability and maintenance are worse
>than for a simple metal antenna.

The idea of using plasma as a conductive element in an antenna is quite
clever (of course, wasn't that one of the goals of HAARP.. to modulate a
very large ionized cloud in the upper atmosphere to make a reasonably
efficient ELF radiator?). It's quite difficult to find anything
substantive on Markland's site (or on logical links from there), but this
is quite characteristic of high-tech companies trying to get access to
capital markets. Lots of powerpoint and dazzle, but not much substance.

I found no citations in the "Web of Science" for T R Anderson where plasma
or antenna appears in the title.

However, looking through IEEE's search engine, there is a paper by T.R.
Anderson (of Anderson Sci., Inc., with the same email address used in one
of the SBIR proposals) titled
Electromagnetic noise from frequency driven and transient plasmas
Anderson, T.R.;
Electromagnetic Compatibility, 2002 IEEE International Symposium
on ,Volume: 1 , 19-23 Aug. 2002
Pages:498 - 501 vol.1

A quick glance over the paper shows that it is relevant to the "noise from
plasma issue".

Another useful citation might be:
Control of electromagnetic interference from arc and electron beam welding
by controlling the physical parameters in arc or electron beam theoretical
model
Anderson, T.R.;
Electromagnetic Compatibility, 2000. IEEE International Symposium on ,
Volume: 2 , 21-25 Aug. 2000
Pages:695 - 698 vol.2

The frequency selective surface ones (only abstracts, from what I could find):
Plasma frequency selective surfaces
Anderson, T.; Alexeff, I.; Raynolds, J.;
Plasma Science, 2003. ICOPS 2003. IEEE Conference Record - Abstracts. The
30th International Conference on , 2-5 June 2003
Pages:237
Theory and experiments of plasma antenna radiation emitted through plasma
apertures or windows with suppressed back and side lobes
Anderson, T.; Alexeff, I.;
Plasma Science, 2002. ICOPS 2002. IEEE Conference Record - Abstracts. The
29th IEEE International Conference on , 26-30 May 2002
Pages:294

>I have retrieved some information on plasma antennas from the various
>patents on the subject and from Markland's website. Does anyone have more
>(better) sources in which some of the issues with plasma antennas are
>addressed?

And of course, just because it's patented doesn't mean it works very well,
or at all, viz. US Patent 6024810 Hyper-light-speed antenna
(I find the fact that the inventor says that it will improve plant growth
particularly significant)

>Also: how mature is the technology at the moment? The pictures on
>Markland's site show a number of antennas (which presumably work?). On the
>other hand, the technology is still listed under the subject "emerging
>technologies" of their website. Does anyone know if there are companies
>actually offering plasma antennas for sale? Currently most of the research
>and application looks to be US DoD only!

Interesting that Markland doesn't put the reports they produced under their
ONR and SBIR contracts online. They probably don't actually have them,
because some quick searching of databases shows that Markland didn't
actually do the work:

For instance, the SBIR contract they cite on their web site
DASG60-02-C-0055 was awarded to a company called ASI Technology Corp, with
a principal investigator of Theodore Anderson
ASI does/did a lot of work in Plasma antennae: DASG60-02-P-0033,
N00178-03-C-1013, etc.

Perhaps Markland Technology has bought/licensed the work of Dr. Anderson
from ASI?
I note that the '746 patent gives Anderson as residing in Masachusetts (a
long way from Henderson NV, where ASI is based) and also has Igor Alexeff
as a co-inventor.

Many of Anderson's earlier patents are assigned to the USA, usually an
indication that the work was done under government contract (perhaps the
SBIR and ONR contracts Markland cites on their website?)

 From a press release of ASI:

ASI will be using certain equipment and facilities at the University of
Tennessee - Knoxville to support this effort. The principal investigator
under the contract is ASI's Theodore Anderson, Ph.D., a plasma physicist
and mathematician.

Anderson is the inventor of a number of plasma antenna innovations.

Jerry Polis, president, stated, "We have performed pioneering plasma
science on antennas, communication links and shields. This contract
furthers our patent-pending shielding technology for the protection of
antennas and electronics from interference. This technology has
applications in protecting commercial systems as well."

-----------

As with many things where the technology might have marketable aspects,
it's tough to track down the real meat, if there is any...

Odd thing of course that Anderson is in NY or MA, but the company is in
Henderson NV (Henderson is essentially a suburb near Las Vegas). Perhaps
there's better tax treatment, etc.

>best regards,
>Jasper van der Graaff

James Lux, P.E.
Spacecraft Telecommunications Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875

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