Can any body tell me EW is related to which engineering field?
I'll give you a broad international answer, Fawad.
At the start, complete high school with algebra.
That's a minimum to be an EW specialist anywhere.
The next level is technical : electro-mechanic, electronic,
computer or any maintenance of related equipment.
Cheers to the support crew who save lives quietly.
At around univ/college degree,
go for pure sciences if so
inclined but most should aim for an advanced IT cursus :
Network, Administration, Engineer, Programmer, Analyst.
Some Armed Forces require you to have a diploma but
others ( those with the most modern techs ) actually form
you into someone able to hold a post in a civilian setting.
And last but it actually starts earlier than the rest so that
I should have listed it first : you need to be a clean sheet
good citizen because the entire domain requires a security
clearance.
Have a great day, Tay.