Ferrite isolators and circulators play a fundamental and valuable role in RF systems. They are passive, ferrite devices that act as traffic conductors for RF energy in a system, routing signals wherever a system designer needs them to go. Their ability to behave nonreciprocally
(non reversible, allowing energy to pass in only one direction through the device) when RF energy is applied to them is very important for a number of applications.When selecting an isolator and/or circulator, it is important to understand some common electrical specifications that tells how well it is capable of performing the application. The three basic specifications for isolators and circulators are insertion
loss, VSWR, and isolation.