Re: NEC-LIST: Letter from Grimes

Hi,
t sounds like a difference of opinion between theory and practice to me as
well. Ask any quantum physicist about electromagnetics and they will tell
you there is no such thing as electric and magnetic fields and that there
are only photons. But, try to predict antenna performance using quantum
mechanics and you'll have a hard time coming up with solutions to antenna
problems. As Mr. Grimes pointed out, this is for people who have the time
and resources to pursue it.
Just my humble opinion,
Roland
-----Original Message-----
From: Altshuler Edward E Civ AFRL/SNHA <Edward.Altshuler_at_hanscom.af.mil>
To: nec-list_at_gweep.ca <nec-list_at_gweep.ca>
Date: Thursday, January 23, 2003 9:04 AM
Subject: NEC-LIST: Letter from Grimes

>Dear Colleague,
>
>The following letter from Prof. Grimes was sent to me and a few other nec
>participants. It was also sent to the nec list but since it has
attachments
>I was told that it did not reach that list. The attachments are
>
>Dale M. Grimes and Craig A. G, "Minimum Q of Electrically Small Antennas:
A
>Critical Review, Microwave and Optical Technology Letters, vol. 28, No. 3,
>Feb. 5 2001, pp. 172-177.
>
>Dale M. Grimes, "Radiation Q of dipole-generated fields," Radio Science,
>vol.34, No.2,pp.281-296, March-April 1999.
>
>For your information, here is the letter.
>
>Gentlemen
>
>Collin's paper attacks a Grimes and Grimes work, the JEWA paper, which we
>had pointed out in a subsequent 1999 Radio Science paper was incorrect.
>Since the Editor handling Collin's paper never contacted us about his work
>(nor allowed a rebuttal) what is left is Collin's trashing of a paper we
had
>already said, in print in a widely read journal, was wrong.
>
>The JEWA paper uses frequency domain analysis which is fine for some
>specific antenna designs, albeit common ones, but is not a general
technique
>suitable for all radiation sources. This is fact. For a general antenna
>design time domain analysis must be used. The reason is simple enough,
>information is lost in the frequency domain that is not in the time domain.
>No one, to our knowledge, has found any errors in the time domain results
>initially presented in the Radio Science paper attached, placed in
>perspective in the Q review paper attached (which summarizes the issue of
Q,
>it's determination, and where Collin's errors are pointed out for the
reader
>to which Collin has made no response), and tied together from an
>electromagnetics perspective (with an improved technique) in the recent
book
>The Electromagnetic Origin of Quantum Theory and Light published by World
>Scientific. We also gave an hour lecture on this at the recent PIERS
>conference, the slides of which are downloadable from
>
>http://www.ee.psu.edu/grimes/publications/
>
>Our point is simple: Determination of radiation Q in mixed modal fields
>requires use of the time domain. The frequency domain is only correct with
>certain limited radiating structures due to missing phase information.
When
>one does the general, complete math correctly a considerable amount of
>insight into physical phenomena regarding electromagnetic emission and
>quantum theory becomes clear. Whether that means we can build a zero-Q
>antenna is an open question, certainly mother nature can.... atoms support
>wavelength to size ratios of hundreds to thousands yet apparently don't
have
>any problems with reactive energy storage.
>
>Why don't you guys read the papers and do the math. A proofs a proof, if
>the math is wrong we would be delighted to know about it. If the math is
>correct then I suggest the EM community might be well advised to consider
>the consequences of it.
>
>I would also suggest if you approach the results of our experimental work
>without bias you might find something interesting going on there. While
>such an antenna is not going to be sold commercially in the near future
>there are clues there for people interested in this field and have the time
>and resources to pursue it.
>
>Respectively, Craig Grimes
>
>
>
>Edward E. Altshuler
>Sensors Directorate
>Electromagnetics Technology Division
>80 Scott Drive
>Hanscom AFB, MA 01731-2909
>(781)377-4662
>(781)377-1074 Fax
>
>--
>The NEC-List mailing list <nec-list_at_gweep.ca>
>http://www.gweep.ca/mailman/listinfo.cgi/nec-list
>

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