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| | Near-Far Field - RF Cafe Forums |
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be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
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Below are all of the forum threads, including all
the responses to the original posts.
| maxwell | Post subject: Near-Far Field Posted: Mon Oct 10, 2005 12:25 pm |
| | | | Captain |  |
Joined: Mon Sep 01, 2003 6:59 pm
Posts: 13
Location: Boston | Hey there is a great article linked from the RF Cafe home page on near-field vs. far-field. Definitely worth reading. Good find Kurt. ...  Maxwell
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| UWB_antenna_guy | Post subject: Re: Near-Far Field Posted: Mon Oct 10, 2005 5:20 pm |
| | | | Colonel |  |
Joined: Tue Aug 09, 2005 1:07 pm
Posts: 28 | maxwell wrote: Hey there is a great article linked from the RF Cafe home page on near-field vs. far-field. Definitely worth reading. Good find Kurt. ... Maxwell a link would be nice. Couldn't find the article on the main page
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| Kirt Blattenberger | Post subject: Posted: Mon Oct 10, 2005 9:28 pm |
| | | | Site Admin |  |
Joined: Sun Aug 03, 2003 2:02 pm
Posts: 308
Location: Erie, PA | Greetings UWB_antenna_guy: The article is titled, "The World of the Near Fied," and the link to it is in the Recent Additions list in the right column. The link is replicated here so you don't have to go back to the homepage to get to it. I will be adding a calculator page for obtaining the three near field boundary distances given in the article. http://www.evaluationengineering.com/ar ... _world.asp. _________________ - Kirt Blattenberger  RF Cafe Progenitor & Webmaster
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| Graham | Post subject: Posted: Tue Oct 11, 2005 6:44 am |
| | | | Colonel |  |
Joined: Fri Sep 02, 2005 7:25 pm
Posts: 34
Location: Hampshire UK | Excellent article. For me, its a setback. I always knew to get the probes more than a couple of wavelengths away from the antenna, or more than about 4 antenna dimensions away, whichever was the larger.
That is such a gross rule of thumb, especially in the face of all the graphs this author uses.
The concept explanations originally taught to me about how the energy storage near fields were different in nature to the one that radiates at the speed of light, left a bit to be desired. Here is where I just had to put my faith in the formulae out of the books, without *really* understanding.
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| sag | Post subject: near field for parabolic antennas Posted: Mon Oct 24, 2005 10:23 am |
| | Hay all,
If we are on the subject of near field, how would you define the
near field of a parabolic dish? I mean if you take a 10ft dish operating
at 5GHz you'll get a very large near field area by using the standard rules.
So do you use the dish size to evaluate the far field or you use
the feed size and thus get that the dish is actualy at the far
field of the feed?
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Posted 11/12/2012
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Kirt
