Re: NEC-LIST: Small antennas: can they me multiply resonant?

Good day Alan,

Here are a couple of papers I've written. Volume loading is a way of
getting so much structural capacitance that series resonance can be induced
even for very tiny antennas. Of course, high Q becomes an issue if you go
small enough. The CTHA is essentially a radiating transmission-line
structure which is electrically-small at the first three standing-wave
resonances.

"Volume Loading-A New Principle for Small Antennas", ACES Journal, July '99.

"A Study of the CTHA Based on Analytical Models", IEEE Trans. on Antennas
and Propagation, August, 2001.

Also, there are fractal loops that have resonances below 0.3 wavelength. I
can't find the last article I saw on the subject, you might contact Chip at
fractenna_at_aol.com.

----- Original Message -----
From: <alan.boswell_at_baesystems.com>
To: <dbmiron_at_paulbunyan.net>; <nec-list_at_gweep.ca>
Sent: Tuesday, January 07, 2003 4:53 AM
Subject: RE: NEC-LIST: Small antennas: can they me multiply resonant?

Doug

I am interested in who has found such structures and where the results were
published. An electric element has a small radiation resistance in series
with a capacitive reactance, an magnetic element is the same except the
reactance is inductive. What other sorts are there?

All the best,

Alan

-----Original Message-----
From: D. B. Miron [mailto:dbmiron_at_paulbunyan.net]
Sent: 06 January 2003 19:16
To: NEC-LIST
Subject: Re: NEC-LIST: Small antennas: can they me multiply resonant?

David, Steve, and Alan,

I think most of us working on small antennas define "small" in terms of
wavelength of operation, rather than being subresonant. Some of us have
found structures that don't include lumped elements that have one or more
resonances at wavelengths where the antenna is still small. So, I agree
with Steve's posting.

Doug Miron

----- Original Message -----
From: <alan.boswell_at_baesystems.com>
To: <d.jefferies_at_surrey.ac.uk>; <nec-list_at_gweep.ca>
Sent: Monday, January 06, 2003 11:49 AM
Subject: RE: NEC-LIST: Small antennas: can they me multiply resonant?

David
If you define a small antenna as an antenna operated below its lowest
natural resonant frequency, the question disappears (lumped components must
be disallowed).
Alan

-----Original Message-----
From: David Jefferies [mailto:d.jefferies_at_surrey.ac.uk]
Sent: 06 January 2003 17:02
To: nec-list_at_gweep.ca
Subject: NEC-LIST: Small antennas: can they me multiply resonant?

Dear List,

Revisiting the arguments about the CHU limit on Q for
small (very small) antenna structures, in the light of
my comments about multiple resonances, can a structure
which is very much smaller than the radian sphere
contain multiple radiating resonant elements, or is
it necessarily the case that small antennas are only
singly-resonant?

regards

--
David Jefferies
http://www.ee.surrey.ac.uk/Personal/D.Jefferies/
http://www.eryptick.net/
fax +44 (0)1483 534139 attn D.Jefferies
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