QUESTION

Question

Hello, we have designed a board using this active antenna, and we would like to know what would be the best choice for our application.

The module selected (SIM868) has an internal LNA + SAW configuration. Our device also uses Integra for 2G comms.

So, what would be the best configuration? LNA -> SAW -> LNA -> SAW (M20047) or SAW -> LNA -> LNA -> SAW (M20057)?

Thank you.

Answer 1

Hello Reinoso,
It depends on your antenna, application and environment. If you demand high sensitifity (=low noise figure) and your antenna is selective or you have no strong signals in adjacent bands then put the LNA first. If you expect strong signals beside your band and/or you have a broadband antenna then a better way is to start with a SAW filter.
Regards
Guenther

Answer 2

Hello...I’m currently designing a circuit board with the SIM868 module, from the RF design application reference they recommend to use an ferrite bead FB101 to filtering the noise from DC-DC.
Is this a best practice to do ? because i see in all other applications they don’t use that.