I want to calibrate different parameters like gain, 1db depression point of RF amplifier from 150 kHz to 80 MHz and 80 MHz to 3 GHz 50W. which attenuator is suitable to use for measuring instrument safety.

 

I want to calibrate [measure] different parameters like gain, 1db depression point of RF amplifier from 150 kHz to 80 MHz and 80 MHz to 3 GHz 50W. which attenuator is suitable to use for measuring instrument safety.

It depends entirely on the instrument. Calibration is something you do to an instrument. Measure is something you do to an amplifier.