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I'm planning to design a board with both GSM and GPS/Glonass functionality so I picked Simcom's SIM5360 module which seems right for me. It has three antennas, one for GSM, one for GPS/Glonass and the other is marked as diversity antenna. Now I looked inside its documents but they never explained what is a diversity antenna and is it necessary to use it. Can I just leave it unconnected?

Because having 3 antennas would make my design very complicated to use in a special environment I'm planning to use and it would make a lot of extra connections and it's just not practical. Why would there be a need for diversity antenna when there are already two other antennas?

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Diversity antenna is not needed for HSPA+. We have been using module like this and download speeds are fine. Their evaluation board also works just fine without diversity antenna. I've been in contact with SIMCom official distributor FAE, who has confirmed this from manufacturer. In case you are not planning to use diversity, leave the DIV_ANT pin floating.

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Diversity antenna uses for GSM functionality, it improves signal quality (read any article about antenna diversity, e.g. on wiki). Only thing which is told in datasheets - 2G network will work without it (it's clear from functional diagram).

If you want to remove it - you'd better consult directly with SIMCom, they will delegate your question to your local SIMCom representative and they'll answer. But if you can correctly place that antenna in your device - it's better with it than without.

P.S. SIMCom does have SIM5320, which haven't diversity antenna and Glonass support (but pin-to-pin compatible with SIM5360). From my experience - pure GPS receivers works better than GNSS (don't know why)

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  • \$\begingroup\$ As you said from functional diagram it is clear that diversity antenna has something to do with WCDMA RF Frontend only. On the other hand I need the 3G communication capability. I don't know if not using diversity antenna is going to affect that. I have looked at SIM5320 before but according to customer's need it should support Glonass as well so I can't use it. I just sent an email to simcom but who knows if they ever gonna answer that! By the way do you know any other good GSM+GPS module that supports 3G and Glonass as well with a reasonable price? \$\endgroup\$ – mostafanfs Sep 15 '15 at 12:52
  • \$\begingroup\$ In my country 3G is only starting, and we're using SIM5320, and it perfectly works with HSDPA technology (it haven't DIV antenna). So i guess DIV antenna absence may affect only on performance of internet link. SIMCom always answers on customer's questions (telling you from my experience), and they have most reasonable price among "stable" M2M modems (some professionals say they have most stable TCP stack). You could look at Neoway or Quectel products, but they have a bunch of "lags" (which can be avoided by accurate programming but anyway...). \$\endgroup\$ – Looongcat Sep 16 '15 at 6:49
  • \$\begingroup\$ Thank you. What email did you used to make contact? I have sent couple of questions to m2m@m2m-com.com but nothing so far. By the way do you have SIM5320 cad files like footprint? Seems like they're pin and package compatible so I figured I'd save some time instead of drawing it on my own. \$\endgroup\$ – mostafanfs Sep 16 '15 at 8:45
  • \$\begingroup\$ I'm working in Altium, and have both footprints (5320 and 5360). If it's fittable for you - i can attach it to the comment. About SIMCom communicating - i'm talking directly with local representative and don't remember original address, sorry :( \$\endgroup\$ – Looongcat Sep 16 '15 at 9:20
  • \$\begingroup\$ Thank you. I'm working in Altium either. If you could attach those footprints somehow I'd really appreciate it. That would save me lots of troubles! \$\endgroup\$ – mostafanfs Sep 16 '15 at 9:49

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