Hi we have designed a board using a dual band Wi-Fi module from redpine signals (rs 9113). While performing radiated immunity test , the board fails to transmit when board is exposed to 2.4 - 2.44 ghz band of frequencies .can
anyone help me on this .immunity test level is 3v/m

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    \$\begingroup\$ I guess you want to know what specific component is causing the module not to transmit eh? \$\endgroup\$ – Andy aka Apr 22 '17 at 8:40
  • \$\begingroup\$ yes,which one?@Andyaka \$\endgroup\$ – karthik Apr 27 '17 at 10:59

Assuming you don't have a problem with your device (which we can't possibly guess, since you gave us zero info about your design...):

That might or might not be correct behaviour!

Wifi modules must disable transmission in a band if they detect certain types of signals there (weather radar, IIRC). And you might just be triggering that.

Edit ah, DFS (Dynamic Frequency Selection), the aforementioned radar avoidance technique, applies to the 5 GHz bands, as far as I can tell, which doesn't rule out it's not also active on 2.4 GHz – it's not a bad thing to avoid channels with broadband interferers.

However, that might usually be handled by the host controlling your RS9113; now, if only you told us anything about that...

So, however:

immunity test level is 3v/m

Um, 3 V/m over lossless free space?

If my math doesn't completely fail me:

A Wifi transmitter can legally transmit 20dBm EIRP (and would transmit significantly less to a close by station).

At a distance of 18cm, that would be around 3V/m. Since 18cm is by all practical means still near field of the transmit antenna, no Wifi device would ever have to operate under such field strengths.

Your transceiver might just be shutting down to avoid damage to the receive frontend. It would make no sense to transmit in this scenario – the receiver is totally deafened.


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