IWR1642: Silver oxidation - antenna coating or alternate finish ?

Massimo Liistro

Prodigy 190 points

Part Number: IWR1642

Hi,

I am referring to :

https://e2e.ti.com/support/sensors/f/1023/t/858269?AWR1243-Alternative-mmWave-boards-plating

Does TI provide any updated information about ensuring the preservation of the silver patch antenna in the long run ?

I am referring to using another RF-friendly surface finish or conformal coating.

Any guidance concerning this topic would be very appreciated.

I know silver oxidation will slightly degrade the performance at first, but in the end the traces may be totally wiped.

Thank you,

Massimo

over 5 years ago

0 CHETHAN KUMAR Y.B. over 5 years ago

TI__Mastermind 25835 points

Massimo,

All our EVMs have been developed with immersion silver surface finish. Prolonged exposure to air causes silver to oxidize however it shouldn't degrade the RF performance.

Please refer to the "Choosing Circuit Materials for Millimeter Wave Applications" article written by Rogers. There is extensive study conducted by the Rogers and even with 2.5 Years of ageing it did not show significant degradation.

https://highfrequencyelectronics.com/Archives/Jul13/1307_HFE_CircuitMaterials.pdf

Alternatively, you could explore OSP (Organic Solderability Preservative) surface finish, which also considered good for mmWave application. But it may have limited number of high temperature cycles it can with stand.

Thanks and regards,

CHETHAN KUMAR Y.B.

0 Massimo Liistro over 5 years ago in reply to CHETHAN KUMAR Y.B.

Prodigy 190 points

Thank you for this information and suggestion.

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IWR1642: Silver oxidation - antenna coating or alternate finish ?