Using Isolators to Protect RF Amplifiers

This article explains the function of an isolator when used at the output of an amplifier. We’ll also link to basic information about RF Isolators and RF Amplifiers.

RF Amplifier Function: An RF amplifier is a device that takes an input signal and amplifies it, producing a stronger signal at its output.

RF Isolator Function: An RF isolator is a device that allows signals to pass in only one direction – from its input port to its output port. It blocks signals from traveling in the reverse direction (from output to input).

To perform this function effectively, RF isolators are designed with low insertion loss and high isolation. You can see this depicted in the image above.

RF amplifiers are often expensive components. By placing an isolator at the amplifier’s output, we prevent reflections from reaching the amplifier itself, thanks to the isolator’s high isolation. This protects the amplifier from potential damage and saves costs in the long run. Furthermore, the isolator’s low insertion loss ensures it doesn’t significantly weaken the signal passing through the RF chain.

In essence, the isolator acts as a safeguard for the amplifier, preventing potentially damaging reflected signals from travelling back into the amplifier while minimizing signal attenuation.