A duplexer is a device that enables a single antenna to be used for both transmitting and receiving signals on different frequencies. It allows the antenna to be connected to both the transmitter and the receiver at the same time, while isolating the signals from each other. This is particularly useful in situations where space or infrastructure is limited, as it allows multiple radios to share a single antenna.
A combiner, on the other hand, is a device that allows multiple transmitters to share a single antenna for transmitting signals. It is used to combine the signals from each transmitter and send them through a common feedline to the antenna. This can help save space, reduce cost and improve system efficiency by allowing multiple transmitters to use the same antenna.
Both duplexers and combiners are commonly used in the antenna environment, particularly in wireless communication systems such as cellular networks, radio and television broadcasting, and military communications systems.