Similar in many ways to a Power Divider, Directional Couplers are used to split signal between two devices or antennas. The major difference is that it is an unequal split, sending a greater amount of signal through the Output port than the Coupled port.
For example, a 6 dB coupler permits 75% of signal to travel from Input to Output, with 25% flowing out the Coupled port. This results in the Output signal reducing by 1.2 dB, and the Coupled signal being a full 6 dB weaker than the Input.
Coupling values for each series range from 5 to 30 dB, with 5, 6, 7, 8, 10, and 15 dB being the most common types used in Powertec’s engineered repeater systems.
The Directionality of Directional Couplers refers to the fact that the coupling value is not bi-directional. That is, signal incident on the “Output” port will not flow to the Coupled port at the Coupling value, instead Inter-Port Isolation will indicate the estimated signal level.
Directional Couplers are used extensively in the construction of distributed antenna systems in order to achieve correct balancing.