Is there a possibility to add a stronger and longer Wifi antenna?

I think this is the original Wifi antenna, red marked?
Is there a possibility to add an extra antenna on this connections, red marked?

I ask, because one of the Apollo Futurebit Master Miner with 2 Slaves is behind a Fire Door and there i have no good Wifi connection. Sometimes it works, sometimes not (~15-20% connection quality.)

Thx for your answers
Gr€€tz Biosman

PS: Merry christmas, catholic date, Merry christmas to all orthodox at 06.01