Metal contact has come off the mainboard. Help! What antenna it can be

Anyone knows what antenna are located in the lower bumper? Coz one metal contact, which sits right beside the earphone port, has accidentally come off the mainboard. And this contact should connect with another metal clip inside the lower bumper. It must function as some kind of antenna. But what exactly? So far I haven’t noticed anything obviously wrong with the reception after the damage, but still upset about this.