Power dividers go by many names, including directional couplers, power combiners (when used in reverse), and power splitters are considered passive devices most commonly used for radio technology purposes. The purpose of these devices is to couple a specific amount of electromagnetic power in a port or transmission line, which allows a signal to be useful for another circuit.
With directional couplers, a crucial feature is that they only couple the power flowing in a single direction. The power entering the output port is coupled to the specific, isolated port, but not to the coupled port. Directional couplers, work to split the power equally between two ports. This design is referred to as a hybrid coupler, such as the 180 degree hybrid combiner.
Understanding Directional Couplers
Usually, the construction of directional couplers involves the use of two coupled transmission lines that are set close enough together so the energy passing through one is coupled to the other. This is a technique that’s favored at microwave frequencies where the transmission line design is used to implement several circuit elements.
However, a lumped component device is also possible at lower frequencies, including the audio frequencies used for telephony. With microwave frequencies, specifically the higher bands, the waveguide designs can be used. Many of the waveguide couplers respond to one of the conducting transmission line designs; however, there are other types that are unique to the specific waveguide.
The Use of Power Dividers and Directional Couplers
There are many applications for power dividers and directional couplers. These include creating a signal sample for monitoring or measurement, feedback, antenna beam forming, combining feeds from and to antennas, separating the received and transmitted signals on the telephone lines, and creating taps for systems distributed by cable, such as cable TV.
Understanding the use of these couplers and combiners is the best way to ensure they are used properly. Be sure to keep this information in mind to know the benefits they can offer.