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# Wireles Polarity

Posted on 2004-09-16
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For you physics people out there.
If you have polarized windows you know that your wireless internet is affected.  Now is this due to the polarity o fthe windows being perpendicular to the polarity of your wireless antennae?  If so can you get one parallel with the polarized windows and be unaffected other than by the density of hte glass. Or are you up a creek?  I am assuming that light polarity and radio polarity are two different things as I havent taken a physics class in a long time.
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Question by:ASW3382
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ID: 12081098
*grin*  What did you say..??  Sorry, just have never seen this type of question asked in this thread before...  I will be interested in seeing the other experts answer this one..!!!
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darkfriend earned 2000 total points
ID: 12081724
DANG!  Are you for real asking this?  Well let me put my physics cap on.  I was a physics major before flopping to computer science.  I would say in essence the polarized glass would effect the radio waves much the same as the light waves.  Radio waves and light waves are very similiar, in-fact.  They are both electromagnetic radiation.  The light waves just have a much higher frequency and subsequently much smaller wavelength.  The light waves are something like 300 Terahertz, where the Wi-Fi wave is 2.4 Gigahertz.  If the parallel polarized glass is setup to block light waves it will surely block the same amount (or more) of the radio waves.  Of course those waves traveling parallel to the grid will still pass through.  And so, if I read your question correctly, you are trying to theorize that radio waves are capable of traveling all in one parallel wave.  I would say they are traveling in every possible parallel/perpendicular direction and the spread caused by antennae position is mearly a mass direction rather than a surf-like water wave projection.  So the radio waves would still pass through the polarized glass, but only those waves traveling virtually parallel to the polarized direction of the grid.  Of course you still have to consider the thickness and composition of the polarized material but why make it COMPLICATED.
-DF
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ID: 12083192
Bravo darkfriend..!!!

FE
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ID: 12084325
Sorry I know it was an odd question, but with polarized glass becoming a more prevalent addition to businesses I thought I would check out my theory.  I knew a little about light polarization from my Hardware classes as a CS major ;) But I didnt know if the same principle applied to radio waves.  When I checked out anteanaes online I noticed that there were vertical, horizontal and circular polarizations.  So for one business I am working with they have very large polarized windows. So I get a strong signal inside but when I go outside and close the door, bam, the signal is down to practically nothing, and I am only 10 feet away from the access point.
Thanks for the answer darkfriend!  That was the kind of answer I was looking for, hopefully google will crawl this thread soon so when other people look it up the can see your nice answer!  Of course I cannot verify that it is correct quite yet but I will trust you.
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ID: 12084550
Nice to have a physics major among the EE experts..!!  And it sure sounds correct to me..  :)
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ID: 12090178
Well thanks for the praise.  Polarization is a small topic in the physics world but the waves and such are always hit pretty hard.  It's hard to make a rebuttal to something that has gone virtually untested.  But it sounds like you have field tested it a little and found the result to be that the polarized glass does effect the signal pass through.  Now we just have to find a way around it.  The best bet so far are the repeaters and range extenders to bounce the signal around the offending objects.  I've found the omni-directional antennas to be fairly poor.  The directional antennas seem to push all the power to a stronger signal in one particular direction but the impermeable objects still remain.  We'll all have to keep testing it.
-DF
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Expert Comment

ID: 23914382
Radio waves to have a polarity. The electric field of the radio wave is either horizontal or vertical and this is how we refer to its polarity (there is also circular polarity but that is something different and very few if any wifi devices have a reason to use it). In the case of light, it  also has a polarity.

Because light is at a much higher frequency, it interacts with non-conductive materials in a way that radio waves usually do not. As a result of this, the attenuation of a 2.4GHz signal from the light-polarizing material from the type of material (e.g. it is conductive) rather than from the polarization of it. If it was really the polarizing wave guides of the light-polarizing material, the 2.4GHz wave which is about 13cm in size would be entirely blocked.

It is much more likely that there is something conductive which is absorbing it to some degree. This could be the mirror-like additive to the exterior of the window or the polarizing material itself. This is somewhat like the Faraday effect.
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ID: 23918735
Wow havent thought about this question in ages,  thanks for the comment vrmetro,  My theory was that the glass was blocking ALL of the signal, the only signal making it to the exterior of the window was incidental, eg it was the waves that made it around the glass, or the signal itself was not completely polarized.  I have little education in physics but I am a student of it.  Such a facinating field.
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ID: 23920138
Yes, what a surprise comment!  Nice to see experts in this field chiming in!

FE
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ID: 23926065
It's nice to get a refresher of those elements of the field that we do not revisit very often. This was an interesting post in its day, and is still an interesting read. I enjoy the additional comments.
~df
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