Power Dividers

The study of power dividers is important for anyone planning to dive into radio technology. Power dividers and directional couplers are passive devices used extensively in the field of radio technology. Generally speaking, they couple part of the transmission power in a transmission line by a known amount out through another port. They do this by using two transmission lines that are set close enough together so that energy passing through one is coupled to the other.

Most power dividers will have four ports. These include the input, transmitted, coupled, and isolated ports.

Under optimum conditions, the input power would be divided equally between the output ports. Power dividers are made up of multiple couplers and, like couplers, may be reversed and used as multiplexers. But there can be issues with this set up.

One of the drawbacks is that for a four channel multiplexer, the output consists of only 1/4 the power from each, and is relatively inefficient. Lossless multiplexing can only be done with filter networks. There can be many configurations for filter networks and you should be careful to use the proper one in order to maximize the results.

It was first discovered that coherent power division was accomplished by means of simple Tee junctions. At microwave frequencies, waveguide tees have two possible forms - the H-Plane or the E-Plane. These two junctions split power equally, but because of the different field configurations at the junction, the electric fields at the output arms are in-phase for the H-Plane tee and are anti-phase for the E-Plane tee.

For power dividers to be more effective, the combination of these two tees to form a hybrid tee allowed the realization of a four-port component which could perform the vector sum (Σ) and difference (Δ) of two coherent microwave signals. This device is known as the magic tee.

Anyone interested in radio technology or design should spend time learning more about the uses and drawbacks of power dividers. The best way to learn more about this subject is to spend time reading up on it and then spending an equal amount of time reading various schematics that deal with the uses of network filters and various tee constructions.

A good working knowledge of schematics is necessary in order to understand the principles and theories behind power dividers. You can find a lot of information on this subject either online or at your local library.