QUESTION

Question

I'd like to know if there is a recommended tuning strategy for selecting the components R1 and L1 connecting pins T-L and T-R respectively to ground.  Reading between the lines in the datasheet, a good starting point for R1 is a 0-ohm link, but there is no guidance for the choice of L1.

Answer 1

Hello Andrew,

Unfortunately there is no specific tuning strategy as your implementation will vary. The best way is to isolate the antenna from the other components with a pigtail coax cable, populate the 2 matching components with 0 ohm resistors, and see where your resonance is via a network analyzer. Then you can use the Smith chart to see what components you need to shift your resonance into band.

Hope that helps,

Dan Dobransky

Comments

Thank you for the answer, that helped me, but on the DEV board of the m20047, which component is used there at the place of L1?

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Hi Andrew,

L1 should be a 47nH inductor and is used as an RF choke on the VCC supply line. Page 8 on the data sheet spells out what component values to use.

Best regards,

Geoff S.