Hello -- Question regarding feed point on a patch

[chet12]

Hi Everybody,

I am working on the GPS patch shown in this diagram:

http://home.iae.nl/users/plundahl/antenne/patchtek.gif

Of course this plan is for right-hand circular polarization. If I wanted to change it to left-hand circular, should I simply move the probe feed point across the diagonal? Or is there another location?

Thanks for your help

 

[toulouse]

For references you can read Chapter 8 of Microstrip antenna Design Handbook by Garg, Bhartia, Bahl and Ittipiboon.

You should feed the antenna on the other diagonal of the patch to get left hand polar... or feed the patch by the axe of symetry and truncate two oposites corners of the patch to get circular polarisation (have a look at the Ansoft Ensemble demo "design of circulary polarised rectangular patch"

To shorter the dimentions of your antenna you can use another dielectric than air ! (I tested a 2.45 Ghz linear polarised patch made with 1.6 mm thin Epoxi FR4, that's working just fine... another patch, on the table is made with Arlon AD 350 [epsilon R= 3.5] see my web site

http://www.emcrf.hpg.com.br)

Hope this help...



Thomas K.

http://www.genius.org.br

http://www.emcrf.hpg.com.br