Custom Search
Over 9,000 pages indexed!
Your Host
Click here to read about RF CafeKirt
Blattenberger
... single-handedly
redefining what an
engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5CCG (5th MOB):
My USAF radar shop

Hobby & Fun

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse riding business website - lots of info

Doggy Dynasty:
My son-in-law's dog training business
•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<
Job Board
About RF Cafe©
RF Cafe E-Mail
Product & Service
Directory		 Engineering
Jobs
Personally Selected
Manufacturers		 Employers Only
(no recruiters)
Near vs. Far Field - RF Cafe Forums
Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would 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. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


Jose Arrina
 Post subject: Near vs. Far Field
Posted: Thu Mar 30, 2006 9:23 am 
 
Lieutenant
User avatar

Joined: Thu Mar 30, 2006 9:01 am
Posts: 4
Hi guys,

I have searched around the Internet for a definite definition of where the transition between near filed and far field lie. I see a lot of rules of thumb, and they vary from something like lambda/4 to 10*lambda. There has to be a truly technical definition that the measurement standard houses use. If would appreciate it if you could point me to one or more documents that declare ye verily this be the standard ;-).

Thanks, and have a good day.

_________________
... Jose' Arrina


 
   
 
Kirt Blattenberger
 Post subject
Posted: Thu Mar 30, 2006 1:13 pm 
 
Site Admin
User avatar

Joined: Sun Aug 03, 2003 2:02 pm
Posts: 308
Location: Erie, PA
Greetings Jose':

A while back, Evaluation Engineering published a good article on the subject (1). I used their equations to create a calculator (2) that you can plug the DUT antenna dimension into and get a table & graph. The definition given agrees with what a lot of other field measurement papers use for the near field and far field regions. Here is another paper to consider (3); Figure 3 is a good picture of what's happening.


(1) http://www.evaluationengineering.com/archive/articles/1005/1005the_world.asp

(2) http://www.rfcafe.com/references/electrical/near-far-field.htm

(3) http://www.conformity.com/0102reflections.html

.

_________________
- Kirt Blattenberger :smt024
RF Cafe Progenitor & Webmaster


 



Posted  11/12/2012

RF Cafe Software

RF Cascade Workbook
 RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

Smith Chart™ for Excel
Smith Chart™ for Visio
RF & EE Symbols Word
RF Stencils for Visio
A Disruptive Web Presence™

Custom Search
Over 9,000 pages indexed!
 Read About RF Cafe
Webmaster: Kirt Blattenberger
KB3UON

Product & Service Directory
Personally Selected Manufacturers

 RF Cafe T-Shirts & Mugs
Calculator Workbook
RF Workbench
Please Support My Advertisers