If you are suffering from Weak Lte signal in your Zain Lte 4G router , i guess the best option is to get external antenna for it .
Zain router can support two Lte external Antenna from the back of the device
be careful dont buy any antenna from Kuwait market , make sure you get 1800 Mhz antenna . most kuwait shop are selling WIFI which is 2.4 Mh antenna claiming its for Lte , also some type ZAIN antenna on back of it and this is wrong .
if you like to get an antenna online you can get it from amazon.co.uk ( Lte Zain Compatible ). DeLock is the only one i could find online , Below it specification