Antenna in metal enclosure for NRF9160

[Maxim]

Hi,

We are looking for information about the possibility to integrate the NRF9160 in our new product which is integrated in a sealed metal enclosure.

I have not made any measurements for now, but i'm pretty sure that the emission/reception will be affected by the enclosure.

Our problem is that this box will be placed in extreme condition (exterior, on public way) and we can't place external antenna outside the box because of vandalism and unsightly aspect (from our client specification).

I have found this interesting document about antenna integration in metal enclosure 4 ways to increase wireless antenna performance in metal devices but the multilayer antenna are not available for LTE-M frequencies.

So how we can deal with this problematics and can you give us an advice about an antenna model for NRF9160 compatible with our application (ceramic or with UFL connector).

Thanks you,
Maxim

[bjorn-spockeli]

HI Maxim, 

the multilayer antenna would still need to be placed on the outside of the enclosure with a connection going into the enclosure. Wouldnt this be just or even more vulnerable to vandalism than a rugged external antenna?

If there is a hard requirement from the client that no external antenna should be used, then I think your only option is to create a "window" with a material that is non-metal. A better solution would probably to find a non-metal enclosure material that is rugged/robust. 

Best regards

Bjørn

[Maxim]

Thanks you for your answer, we are going to use a rugged external antenna for LTE-M finally, we have found this one which seems to be a good alternative:  https://www.siretta.com/products/antennas/tango-27/

Maxim

[bjorn-spockeli]

HI Maxim,

seems like a good solution. 

Best regards

Bjørn