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I recently came across a phone (Samsung Galaxy Grand Prime SM-G530f) with trouble getting any network signal, I did some troubleshooting and ended up finding out that one of the pin(the GSM pin) to the antenna was torn and it ripped two traces connected to it, I have never worked on any antenna related task before therefore this was new to me.

I googled and found the schematics for the phone in order to see where the traces lead to, but I am not able to make sense of how the antenna is connected to the motherboard.

Here is a snippet from the schematics: The antenna circuitry

enter image description here

Here are the pins that connect to the antenna + the antenna (I don't have the phone right now so I am using the closest images I could get for context)

The GND and GSM pins The Antenna

The pin ANT101 (GND pin) is supposed to be ground which makes sense but what I can't figure out is the ANT102 pin (GSM pin) , it seems to me that it is also essentially connected to the ground and any circuitry beyond it is useless.

How then is the signal from the antenna received?, is this how all antennas are connected?

The full schematics are available here for anyone interested, page 25 and 27 show the complete Antenna circuitry.

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  • \$\begingroup\$ how do you figure you've got broken traces? No, this is not how all antennas are connected, but requiring a ground and an unbalanced signal connection is pretty common, yes. Antennas are a pretty wide topic, to be honest. \$\endgroup\$ – Marcus Müller Dec 15 '18 at 13:44
  • \$\begingroup\$ But regarding your "both seem to be connected to ground": Without knowing what these connectors actually look like, I'll go for "your circuit analysis is wrong, but given the lack of photos and other information, we can't help you tell in which way". \$\endgroup\$ – Marcus Müller Dec 15 '18 at 13:47
  • \$\begingroup\$ And where did you get those schematics from? Maybe from someone that does not know the difference between a stripline and a wire? \$\endgroup\$ – Edgar Brown Dec 15 '18 at 14:25
  • \$\begingroup\$ This question is missing too much to be answerable. It happens that there are types of antennas which are entirely at ground from the perspective of a low frequency (continuity tester, etc), but not at RF, however it's not clear that one would be used and it would probably not be shown as you have depicted on a schematic. \$\endgroup\$ – Chris Stratton Dec 15 '18 at 15:58
  • \$\begingroup\$ @EdgarBrown As far as I know they are the official schematics from Samsung \$\endgroup\$ – AguThadeus Dec 15 '18 at 17:47

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