[Top] [All Lists]

Re: [TowerTalk] Isolated Mode Antenna Technology

To: Bill Aycock <>
Subject: Re: [TowerTalk] Isolated Mode Antenna Technology
From: "Roger (K8RI)" <>
Date: Sun, 20 Dec 2009 17:18:38 -0500
List-post: <">>
If I read it correctly and bear in mind it's been 20 years since I did 
"To me" the math just looks like they are calculating the power Vs 
polarization from angles of zero to Pi/2 and 0 to 360 degrees although 
I'm more than a little hazy on double integrals.

Bill I think it was you that said it looked more like an add than 
technical paper with which I agree.
It doesn't look like that big a breakthrough to me. I disagree with 
their conclusion that two antennas with completely orthogonal patterns 
come up with zero except in mathematics. These are very small antennas 
apparently operating at angles to each other in the near field, possibly 
with a phase delay thrown in.
I can see where using phasing and feed point positioning how they can 
end up with multiple feeds at different phase angles, polarization, or 
even frequency from an intellectual approach, but I'd doubt it's that 
simple in real life, easy, or efficient.  Then again, I said I was 
pretty hazy on the math and they didn't define all of the terms.

"To me" It looks like they are trying to run full duplex 
(spatio-temporal = location and time = position and phase or frequency?) 
on something like a cell phone.

IOW I don't know any more than any one else in here. <:-))


Roger (K8RI)
Bill Aycock wrote:
> Thanks, Ed. It read like something put out just to say they had published, 
> perhaps to "be on record".  It was obviously not a "Peer reviewed" thing. I 
> wonder how the timing problem will be handled when one antenna is used for 
> send and receive?
> Bill--W4BSG
> ----- Original Message ----- 
> From: "Ed Callaway" <>
> To: <>
> Sent: Sunday, December 20, 2009 7:22 AM
> Subject: [TowerTalk] Isolated Mode Antenna Technology
>> Bill,
>> I suspect that the article made little sense because the actual design of
>> the specific antenna is the "secret sauce" of the authors' company, and 
>> the
>> article is largely a commercial advertisement, not a true technical paper.
>> (Part 2 is available at
>> , but doesn't add 
>> much
>> to the reader's understanding.)
>> However, the idea underneath is a sound one, and is well-known in the art:
>> Given an arbitrarily-shaped radiator, it's possible to feed it at multiple
>> points such that the feedpoints are isolated from each other.  Each feed
>> produces (in general) a different radiation pattern.  Having different
>> radiation patterns is useful in MIMO applications, which count on the
>> uncorrelated multipath propagation between multiple antennas (i.e.,
>> independently-fading signals arriving from multiple directions) to 
>> increase
>> throughput "above" the Shannon Limit for the channel.  In 802.11n
>> (Wi-Fi(tm)) and next-generation cellular systems, the developers are
>> counting on MIMO for this throughput increase but, as a practical matter,
>> having multiple, physically separated antennas on a cell phone is a
>> problem -- there's no room.  Having a single radiating structure but with
>> multiple feeds is a much more practical solution, so that's where the 
>> market
>> for this technology likely will be.
>> Although it doesn't involve feeding at multiple physical points, a simple
>> (perhaps degenerate) example of this concept most relevant to the Tower 
>> Talk
>> world might be two-wire Beverage receiving antennas, the patterns for 
>> which
>> move 180 degrees just by changing from differential to common-mode feed.
>> Note that for DXing this technique is unlikely to be as effective as true,
>> multiple-physical-antenna diversity:  The signal is likely to be coming 
>> from
>> only one direction, and the multiple-feed antenna will produce a DX signal
>> only on one feed (assuming independent patterns).  In a true diversity
>> system, both antenna patterns would be pointed in the direction of the DX,
>> so the DX signal would appear on both feeds, fading independently due to 
>> the
>> antennas' physical separation and providing diversity gain.  In the cell
>> phone MIMO case, the signals are expected to be scattered and arrive from
>> multiple directions, where the different antenna patterns can all be used 
>> to
>> collect the signal(s).
>> Meandering lines, or meanderlines, are runners on a substrate that are
>> physically shortened by having them go back and forth, like queues at
>> Disneyland.  They often look like little square waves when seen on circuit
>> boards, and are the 2-dimensional analogy of 3-dimensional helical
>> structures.  Like helices, they can be used as inductors, resonators, and
>> radiators.
>> Ed Callaway N4II
>> _______________________________________________
>> _______________________________________________
>> TowerTalk mailing list
> _______________________________________________
> _______________________________________________
> TowerTalk mailing list

TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>