Far-Field formula for Broadband Horn - RF Cafe Forums

RF Cafe Forums closed its virtual doors in late 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2012, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts. Here is the full original RF Cafe Forums on Archive.org

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

gui076
 Post subject: Far-Field formula for Broadband Horn
Posted: Wed Jan 26, 2011 6:35 am 
 
Captain

Joined: Mon May 05, 2008 9:56 am

Posts: 15

Location: France

Hello,

I have a question about Far-field conditions.

I know two formulas for the Far-field calculation :

Lambda/2pi and 2D²/Lambda.

My question is about a Broadband Horn like 2-18 GHz.

I don't know if I have to use the 2D²/Lambda even for the low frequency ?

I heard if the antenna was electrically small I had to use the first formula but what is the electrically small definition ? (Aperture size < to Lambda or more ?)

Thanks for your help.

Guillaume

Posted  11/12/2012