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antenna Q factor is low

 
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ATarek
Antenna-Theory.com Newbie


Joined: 06 Mar 2018
Posts: 2

PostPosted: Tue Mar 06, 2018 8:19 am    Post subject: antenna Q factor is low Reply with quote

Hello everyone,

I Have a problem an i need your help,
I am designing a 13.56Mhz antenna for NXP RC522 reader,
following application note AN1445 provided by NXP, the quality factor should be in the range of 35+-10%,

but when i measure the parameters using VNA and calculate the Q factor from it, the result is 13.30,

The application note is not mentioning anything to do when Q < 35,

Can someone please give me guidance,

Regards,
ATarek
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admin
Site Admin


Joined: 03 Jan 2007
Posts: 204

PostPosted: Tue Mar 06, 2018 8:55 pm    Post subject: Reply with quote

If your Q is low, you need to find the loss or maximize inductance

tightly couple your loops, improves your inductance faster than the resistance goes up
if you are backed by metal, you need ferrite
is the ferrite decent? is it spec'd out?
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ATarek
Antenna-Theory.com Newbie


Joined: 06 Mar 2018
Posts: 2

PostPosted: Wed Mar 07, 2018 9:57 am    Post subject: Reply with quote

their is no metal in the environment,
the antenna dimension is as follow,
Lcalc = 1.7uH
width = 50mm
height = 35 mm
Track width = 0.4046 mm
spacing between loops = 0.5954mm
number of loops = 4
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