Hello everyone i am new to this world before i start i need some doubts to be clarify kindly help
1) what does port signifies attached at both input and output
2)what does dBm signifies and have read in most of publications that input power ranges from -10dBm to -120dBm cant able to relate input power with dBm
3) why we talk about power gain(S21) not voltage gain(pss analysis) and which of the two  is important in designing mixer, LNA etc.
4) How Idd and gain is decided.
thanks in advance