BLE antenna switching on/off while transmitting

[xinyangt]

Hello,

We are using a BLE module based on nRF52832 with a U.FL connector for external antenna connection. One of our automated tests requires we turn off/on the antenna during transmitting to simulate BLE disconnection caused by poor signal (e.g. device moves too far away).

Upon a bit researching, our current idea is to use an RF switch to switch between the antenna and a 50-ohm resistor termination. But our concern is we are not sure if, when the switch actuates, the signal reflection from the momentary unterminated channel will damage the RF transceiver on the nRF chip.

Our guess is no because the transceiver on the chip is relatively low power and the switching time of the switch can be very short. I did not find information in the nRF52832 datasheet as to the maximum allowed RF live switching time. Could anyone give us a few pointers about this question?

Thanks,

[Elfving]

Hi! 

Interesting concern. The idea with the switch could work, depending on the switch. Though do you need to control the precise timing of when the antenna goes off and on? Otherwise, putting the device in a faraday cage or a lead-blanket might be both best and the easiest.

Regards,

Elfving

[xinyangt]

Hi Elfving,

Thank you for your reply.

We would want to be able to electrically control the on/off of the antenna from another MCU so that we can automate the whole testing process. In this case a faraday cage or a lead-blanket might not be viable.

As for RF switches, what parameters should we look for to decide if one will work for our application? Could you suggest some options for us?

Thanks,