Interference reduction method using a directional coupler in a duplex wireless power transmission system

We propose a method for reducing interference in a duplex wireless power transmission system that uses electromagnetic resonant coupling. Duplex wireless power transmission acts as a directional coupler if it has no loss and is perfectly matched. The proposed method uses this characteristic and the interference is decreased by connecting a directional coupler to the input (or output) ports of a duplex wireless power transmission system. We validate our method by performing simulations for two configurations of duplex wireless power transmission: two sets of oppositely arranged antenna pairs aligned horizontally, and two sets of coaxially arranged antenna pairs aligned vertically. In addition, we show that the location of the isolation port changes depending on the transmission distance in the former configuration.