NRF52832 immunity test problem

[OKAZ]

Immunity test <IEC61000-4-3 (10V/m 80MH-2700MHz)> was conducted on NRF52832-QFAA.

・Frequency increases by 1%.
・Stay time 3 seconds

NRF52832 resets at 2.1 GHz when the radio frequency is increased from 1 GHz.
NRF52832 resets at 2.6 GHz when the radio frequency is decreased from 2.7 GHz.

The figure below is a circuit diagram.
Items marked with * are not mounted.

_

The figure below is a drawing of the board.

Is there any software or hardware countermeasure I can take?

For example...

 Improving BLE immunity on nrf52840 with dynamic frequency hopping 
Radiated immunity test problem 
Immunity Issue 2,3Ghz 
Radiated immunity test problem in home healthcare product

  _____

I would like to know what we can try and the specific steps and methods to do so.

I would like to ask for your help.

[JONATHAN LL]

Hi,

Our devices in only tested against 3V/m so 10V will need some extra additions. There is a similar question here with answers: https://devzone.nordicsemi.com/f/nordic-q-a/95113/radiated-immunity-test-problem-in-home-healthcare-product 

Extra band pass filter before the antenna and metal shielding around the device and radio and its components. 

Regards,
Jonathan

[OKAZ]

 RE: Immunity Issue 2,3Ghz 

Is there a solution to the above?

Due to the structure of the product, it is not possible to place a metal shield; even if it were possible, would it reduce the communication distance?

What kind of bandpass filter should we use and where should it be placed?

[Sigurd]

Hi!

Jonathan is out of office, so I'm replying instead.

It's explained in this post where the filter should be placed.  Radiated immunity test problem in home healthcare product  , the URL to the filter webpage does not work, but I believe the filter referred to in that post is this one: https://www.qorvo.com/products/p/885033