a RF bi-directional signal port that transmits a RF transmission signal propagating as a first traveling wave in a first direction and that receives a RF reception signal propagating as a second traveling wave in a second direction;

a first waveguide having one end that is coupled to an input port that receives the RF transmission signal and having another end that is coupled to the RF bi-directional port; and

a second waveguide positioned proximate to the first waveguide to form a non-reciprocal waveguide device where coupling between the first waveguide and the second waveguide is a function of direction of propagation of traveling waves through the non-reciprocal waveguide device and having an input port that is coupled to an output of a source that generates a third traveling wave and an output port, the second waveguide propagating the third traveling wave in the second direction,

wherein the RF reception signal propagating as the second traveling wave in the first waveguide propagates in the same direction as the third traveling wave propagating in the second direction in the second waveguide such that at least a portion of the received RF reception signal couples from the first waveguide to the second waveguide, and the RF transmission signal propagating as the first traveling wave in the first waveguide propagates in an opposite direction to the third traveling wave propagating in the second direction in the second waveguide, thereby substantially preventing the RF transmission signal from coupling to the second waveguide, and passing substantially all of the RF transmission signal through the first waveguide to the RF bi-directional port.