Radio Ham interviewed about Fractal antenna

I'm surprised to see you say something that narrow. Gain is not the only parameter that can be important for an antenna. Even for ham antennas. Size matters. Bandwidth or multiresonance capability can matter. Loss matters. Impedence matters. Lots of things matter.

Just a reminder that a few days ago I offered to send you a bibliography if some 125 or so papers published just in the IEEE journals on the subject of fractal antennas. And btw the US is not the only place where fractal antenna research is going on.

Go to Google Scholar, and do a search for Exact Phrase "Fractal Antenna*". Narrow it down to the past few years to keep the number of returns manageable. You won't be able to read the full papers on most of them but there are a few you can download; and you can get a feel for most of them by reading the abstracts.

 

From the Skeptics Dictionary: Confirmation Bias

 

Another Fractal Loop (it 2) Reference

This reference is a little cryptic, but its heart is in the right place. The bottom line is that hams have been experimenting with fractal antennas in recent years. That's the reality. I assume there are others; I haven't looked in many years.

http://download.antennex.com/preview/Jan504/fractal.pdf

I suggest looking at the actual data (he made measurements) for FRACtENT IT 2, which is a 12cm by 12cm loop for 2M. He should have etched it. Not hard to graph up and then ink on PCB 'bluepaper': What is found is:

SIZE: 12cm by 12cm ( conventional dipole would be 100cm!)
GAIN: 2 dBd (yes; as is a common convention, a comparison to a dipole. It is 2 dB HIGHER)

SWR: UNDER 1.2:1 from 144 to 146 MHz. That's not a typo.

I am disappointed that with all the unfortunate animosity inveighed against me here by a few, many others were discouraged from commenting. That, is a real, real shame.

I am grateful for the info on the above.

73,
Chip W1YW

 

Some folks here sure have it in spades, Ron!

It is a basic tenet of 'old guard' during paradigm shifts.

73,
Chip W1YW

 

Chip,

You should probably move out of Belmont. I heard that one year, it rained rocks in your neighborhood!

73,

 

Better to be stoned than crucified!

;-)

73,
Chip W1YW

 

Glad to see I'm not the only one who makes typos, Ron. A collinear is NOT a narrow bandwidth antenna, Ron. And, for hams, gain is most important, taking into account a proper transmission line, match, etc. Following that, simplicity in design, construction and physical strength. We're not all enguneers, don't have bending jigs, heliarc welders and such at our disposal. Multiband resonance is a nice feature, and is possible with some HF and VHF designs as we all know.

2 or 3 dBD for a directional array when compared to a simple dipole, yes a third of an S-unit, makes it really not worth the effort to expend to construct even the October 1999 CQ Magazine project. (Only those who have the magazine, thanks to its copyright owner's unwillingness to post its dimensions here, even though he posts an EZNEC figure from the article).

Also, something claimed "novel" in 1999 is not new, by any means.

I suspect that of the 125 papers, some may contain useful comparisons. Interest follows the money, Ron, as you well know. If the market for wide bandwidth, planar substrate-based SHF antennas is significant, much research interest supported by those interested will occur. DOD, I'm sure has interest in planar antennas for aircraft and other vehicle surfaces.

But really, how many of those papers deal with prior art, in the form of Euclidean geometric shapes, now tossed into the definition of being fractals?
I've read the first patent discourse, and it includes all prior art and recognizes Euclidean geometric, repeating shapes as being fractal.

Like I said, fractal is likely now a 'universe' of all repeating antenna geometries.

Hams have little interest in very wide bandwidth antennas with little gain, perhaps even losses. Oh, maybe some that might be experimenting with spread spectrum communications, perhaps.

We're searching for something above sliced bread, Ron. Yes, size can be an issue, but shape too. What with CC&Rs and such, creative emulation of other acceptable shapes would be desireable. Ala flagpoles, roof vents, etc. Speaking of roof vents, perhaps an antenna could be designed to replace the rectangular attic vents under the eaves. A fractal challenge. Or, for those folks who live in CA stucco-over-chicken-wire and tarpaper construction, an antenna to be plastered onto the studs to replace the chicken wire. Who knows, maybe there is an opportunity out there.

Frankly, I'm tired of the ranting salesmanship without design data. Anyone who might be interested could try duplicating that 2-element 10M fractal planar Best "M2" quad in the October 1999 CQ article would appreciate the element lengths table to be posted. So far, all we've seen posted by the copyright holder on here is a copy of Figure 2 from the article, the EZNEC plot.

73.

 

My kingdom for a NAND gate!

 

Ask and Thou Shalt Receive

Ask for Silicon, you'll get some. Not as a rock, either.

Just finished reading an interesting paper entitled Planar Reconfigurable Arrays. Although it is up in the GHz range, it piqued my interest, in light of the above utterance.

As a significant shareholder in a manufacturer of silicon disks, the idea of etching arrays on silicon wafers, yes even such useful fractal shapes as multi-bow-ties, the idea of switching successive segments in and out is fascinating.

And, perhaps for silicon owners, profitable, if it is proliferated.

Imagine. Logical decisions with respect to antenna gain, directivity, bandwidth of interest, etc., can be made and realized by switches imbedded as part of the antenna!! Even within aircraft surfaces!!!

No need to rely on permanently etched freeway daisy chains, just use the etched-in switch to modify the antenna. No need to rotate, just switch!!

The myriad of possibilities this presents is just huge.

Wish for active devices and you get them!!

 

Year 2011 Fractal Antenna Article...starting the year out right

As those who have read my comments here know, I have been patient and gracious providing information on fractal antennas on this thread. I am very disappointed that there are interpretations of my comments as part of some 'flame war', pseudoscience, or deception. That is nothing even remotely correct. I have invited my fellow hams to experiment. I have also articulated that , after 13 years, I am again going to write another ham article on fractal antennas. Dozens of you have sent me email comments--and once again many thanks! This has been extremely helpful in defining what folks really want to see in such an article.

There seems to be some strange consensus that fractals cannot decrease size AND increase bandwidth, while practically attaining other performance characteristics. Of course, I have been saying, publishing, patenting, and making the case for such for decades. However, there is a tendency to give the most recent findings greater weight, and I invite you to view the following article, which other researchers present--that corroborates the fractal element technology in this context (note, that the patents for this are held by my firm):

**************************
On the design of wheel-shaped fractal antennaRaj Kumar, P. Malathi, K. Sawant
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 53, No. 1 January 2011 p.155-158
**************************

You may access thru the link(although you have to have an account for the full article):

http://onlinelibrary.wiley.com/doi/10.1002/mop.25677/abstract

Note the authors report a 900-4500 MHz 2:1 SWR, with dipole or better gain, with a monopole shrunken by 58%

• Dramatically wide bandwidth;
• Excellent SWR, good gain, with no components;
• Shrunken 58% relative to a conventional antenna that works down at 900 MHz.

Of course, this is one of dozens of dozens such articles that demonstrate the fractal advantages, since 2003. I am humbled and take great satisfaction in such corroborations of the technology. I do hope, at some point, that ham radio can again invite a realistic manner of getting the founder of this technology more directly involved with ham designs, and I will be watching reaction to my article so mentioned.

I again suggest that if you want a nice list of such fractal advantage articles, then drop by:

http://fractenna.com/FractalAdvantage.html

where a new additional installment of articles corroborating fractal advantages is provided each month.

I also hope you will enjoy the two (at present) videos accessible thru the link:

http://fractenna.com/whats/whats.html

Remember: the radio amateur's code. Good advice on and off the air.

73,
Chip W1YW

 

Here's the link for the entire article in PDF format at Wileys online library.



http://onlinelibrary.wiley.com/doi/10.1002/mop.25677/pdf


No membership OR password required! ENJOY!!! 73, Vince


_____________________________________________

Vince-----KF5HJK


A 100% Functioning Boat-Anchor !!


"Complexity that works is built up out of modules that work perfectly, layered one over the other."

Kevin Kelly

 

Isn't that wheel on the flag of India?

Seriously, thanks for the link.

 

Chip will dislocate a shoulder patting himself on the back.

 

That particular article doesn't cite Cohen, for some reason. As for being the "founder of this technology", a chronology as seen in the literature may not support the claim. But the story of the young ham in his apartment needing an inconspicuous antenna and "discovering" the fractal is now part of the myth, for sure.

 

Delighted to Hear about Prior Art

I would be delighted to see any and all prior art that relates to fractal element antennas that predates 1988.

Please: let's have a public list for scientific discussion.

73,
Chip W1YW