Compromises when sharing antenna for GPS and LTe

[okwestern]

I am looking at the hardware design of Thingy91, where the antenna is shared by LTE and GPS/GNSS. My system will be connected to a cloud (probably most of the time) and track simultaneously (100 km/h on average, but as high as 250 km/h). With a shared antenna, is this solved time slot divided? And would this strongly compromise LTE and/or GNSS performance? What are other the drawbacks? Could you explain (on a high level) how this is solved? I think this won't be optimal for my system, but I'm always looking to save PCB space and cost.

My other question is:
My first prototype was based on the two separate antennas from 9160DK., but I'm looking to replace the LTE antenna with TE Connectivity pn: 2108783. It is smaller, has much higher gain than both 9160DK and Thingy91, better VSWR than Thingy91 and supports 4 bands. It's also a lot cheaper. Would this be a good choice? And can the same matching network from Thingy91 be used?

[Kaja]

Hi,

so both with shared antenna for LTE and GPS, and with separate antennas there will be a time lots divided between the two, as the GPS receiver only will be on when the LTE is off. 

For best GPS performance and active GPS antenna will probably give you the best results, but antenna choice is complex and depends on many factors including technical and commercial considerations, so you have to consider all the factors for your specific design.

My first prototype was based on the two separate antennas from 9160DK., but I'm looking to replace the LTE antenna with TE Connectivity pn: 2108783. It is smaller, has much higher gain than both 9160DK and Thingy91, better VSWR than Thingy91 and supports 4 bands. It's also a lot cheaper. Would this be a good choice? And can the same matching network from Thingy91 be used?

 If this antenna supports the frequency bands your planning to use, then it's fine to change! For the matching network you should use the one suggested by the antenna vendor! If you want to set up an antenna tuner, switching between different matching networks, you can use the set up from Thingy as a reference, but the matching networks in between should be specific for the antenna you choose to use. 

Under guidelines on the info center you can find the nRF9160 Antenna and RF Interface Guidelines for more help on this topic!

Best regards,
Kaja