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EMI problems with DEMO-CR95HF

Question asked by nothagen.per on Jul 1, 2013
Latest reply on Aug 29, 2014 by ST NFC
Hej!

I just bought a DEMO-CR95HF board to sort out EMI problems that I have with my own design with the CR95HF chip. To my disappointment the DEMO board generates more harmonics than my own design. My measurements can be found at
http://milvus.nothagen.se/pub/strfid/rfid.htm
Also, when I checked the resonance frequency of the antenna I found that it was tuned to 15.2MHz and not 13.56. The resonance frequency was measured using a spectrum analyser with tracking output.

Therefore I wonder:
Is DEMO-CR95HF designed for optimal performance?
Is there any known optimization can can be done to the board to improve performance?
I was planning to use the layout for the circuit between the chip and the antenna. As a consequence of my measurement above I really wonder if you would recommend that? I have also looked at the layout of PLUG-CR95HF-B which is slightly different. Is that layout better?

Best Regards
Per Nothagen
Senior Engineering Manager
Triacon AB

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