[HCARC] "Antennas on A Chip"

Fri Apr 10 21:22:54 EDT 2015

Gary,

I'm an engineer - I don't really care about what is really going on as 
long as I have equations I can use to predict the things I'm interested 
in.  I don't think anyone really knows why a dipole works, but for an 
engineer, it doesn't matter.  I have a model and the equations I need to 
design one.  Let the physicists and mathematicians argue to their hearts 
content.  Their are a few basic rules which allow you to estimate the 
performance of an antenna. The rules basically allow you to determine 
the maximum gain of an antenna given its aperture size in wavelengths, 
the minimum beamwidth given the aperture size and the aperture energy 
distribution  and the sidelobe levels given the aperture distribution.  
For EE's and hams you don't need much more!  Many many years ago, Ed 
Tilton, W1HDQ, the ARRL VHF technical guy for decades, said that adding 
more elements than the guidelines suggested, only made an antenna a 
better bird roost.  Indeed you can cheat a bit and use more elements 
than required.  The result is called a "super gain", actually a better 
term is a "super directive " antenna.  Gain is Directivity multiplied by 
efficiency.  As you know, there is no free lunch so what is the 
penalty.  It seems that once the Gain of the super gain antenna exceeds 
the normal gain for a given aperture by 1 dB, the gain starts going 
down.  This is because as elements get closer and closer together they 
begin to interact more with each other.  These interactions reduce the 
antennas bandwidth and reduce its efficiency.  In effect the Directivity 
keeps increasing but the efficiency is dropping faster than the 
Directivity is increasing so the Gain is headed down. Additionally the 
antenna becomes increasingly difficult to match over any reasonable 
bandwidth.  There are always people out there trying to do just a little 
better.  For most hams I think if we can just get stuff to work as it is 
supposed to we would be the big signal on the band.  No magic is 
required, just knowing what we are doing and actually doing it.

Have fun,

Kerry

On 4/10/2015 6:33 PM, Gary J - N5BAA wrote:
> Damn Kerry - just when I thought that something really cool (as if 100 
> watts talking to Australia is not cool enough - and it is!!) was about 
> to happen and using it I could build a 40/80/160 meter antenna that 
> would fit on a push up pole at 20 feet above the ground, you have to 
> trash all of my dreams and bring it back to earth.  OH well, you can't 
> fault me for at least reading and hoping.  BTW, Fred - your antenna 
> theory belongs in the April QST which I still don't like nor read.  
> Kerry - are you sure there isn't something out there where no one has 
> added 1+1+1 and come up with 3???  We have to have hope don't we??
>
> Gary J
> N5BAA
>
> -----Original Message----- From: Kerry Sandstrom
> Sent: Friday, April 10, 2015 12:15 PM
> To: Gary J - N5BAA ; HCARC Reflector
> Subject: Re: [HCARC] "Antennas on A Chip"
>
> Hi Gary,
>
> I wasn't sure I wanted to get into this discussion but since you want to
> I will join you.  I really can't decide what these guys are talking
> about.  The first thing I think is confusing is when he talks about this
> may be where electromagnetics and quantum mechanics cross over. Well,
> the two great physics theories of the 20th century, quantum mechanics
> and relativity, are consistent with classical physics.  You can solve
> very simple problems with quantum mechanics and relativity.  What
> actually happens is when you are in the world of the ordinary, both
> quantum theory and relativity reduce to classical physics. Classical
> physics is a special case of relativity and quantum theory.  You can't
> do anything with classical physics that you can't also do with quantum
> physics and relativistic physics.  The converse is not true. Classical
> physics is incapable of solving problems involving relativistic and/or
> quantum considerations.  The name of the field that includes
> electromagnetism and quantum physics is called quantum electrodynamics -
> and its not for the casual reader!
>
> I don't believe any one has an adequate understanding of how
> electromagnetic waves are created.  We have various models which can be
> used to predict the generation of electromagnetic waves under specific
> circumstances.  I'm sure you remember from school that there are two
> different descriptions of electromagnetic radiation. One is a particle
> description using photons.  This description is essential to describing
> adequately things like the photoelectric effect.  The second description
> is the wave description which is essential to describing interference
> patterns.  Usually the wave and particle natures of electromagnetic
> waves are discussed with visible light but they apply across the entire
> spectrum from DC to gamma rays and beyond.  From this it should be
> obvious that neither one is a real accurate description of the physics
> of electromagnetic radiation, each only applies to specific situations.
>
> Now when it comes down to the physical size of antennas, antenna theory
> already allows for infinitesimal antennas.  The theory works adequately
> for very small antennas, but of course there is no way to build a true
> infinitesimal antenna!  While very small antennas work just fine they
> suffer from poor efficiency and very broad beams. That is why people
> don't use them except for very special situations.  Note that antenna
> theory has no real concept of how the electromagnetic wave is
> generated.  It just allows you to determine how to control it and use it.
>
> Now lets talk about what I think these guys are up to.  One of the major
> problems with computers is how to move data around on chips. When
> computers had  small memories were slow and handled 8 bits at a time,
> interconnecting conductors were not an issue.  Times have changed.  Now
> computer guys want to talk about massively parallel processors and huge
> parallel access memories.  Think about how you might move 1000 bit
> parallel data around on a chip!  Some work is being done using light
> signals to carry information around the chip.  I think the work
> described in the paper you attached is to look at alternatives to lasers
> and photodetectors on chips.
>
> As far as 160/80/40 m antennas, this has no conceivable application.
> Just my opinion.
>
> Have fun,
>
> Kerry
>
> On 4/10/2015 11:18 AM, Gary J - N5BAA wrote:
>> How might this breakthrough affect lower frequency antennas such as 
>> for 40/80/160 meters??  Might we finally be able to get those 
>> antennas down to a size that is more manageable??  Does height over 
>> ground still apply with this breakthrough??
>>
>> antenna-chip.cfm
>>
>> Gary J
>> N5BAA
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