Circulators
The most common application of a circulator is as a duplexer, allowing the transmitter and receiver in a radio or radar unit to share a common antenna. Energy is transferred from the RF Source to the antenna during transmit, and from the antenna to the receiver during the receive cycle. In each case the circulator functions to isolate the inactive port from the propagated signal. Most importantly, the transmitter output is not passed to the receiver input, preventing the high transmitter power from damaging the sensitive receiver input circuits.
