A Directional Coupler for Power Line Carrier

A method of coupling with directional characteristics can have two significant advantages in power line carrier work: it will remove the need for wavetraps, and it will expand the communication capacity of the power lines. The disadvantage is that system inefficiencies may require more transmitter power. A simple theory for directional couplers is provided, and the theoretical results are compared with measurements from a model 3-phase transmission circuit.