Introduction to Attenuators

Attenuators are passive resistive elements that do the opposite of amplifiers, they kill gain. Why would you want to do that? Suppose your design specification calls for 10 dB gain, with a 1.2:1 maximum VSWR. You search the amplifier vendors, and locate an amplifier in your frequency band, but it has 14.5 dB gain and a lousy 2.5:1 match on the input. By adding an attenuator to the input, you can bring the gain down.