BAE Systems PLC
A HYBRID COUPLER

Abstract:

A hybrid coupler (20) for dividing an input electrical signal to produce first and second output electrical signals which are substantially out of phase, the hybrid coupler including: a first port comprising an input port (12) for receiving the input electrical signal; an input line (14) for coupling the input electrical signal to a slotline (18); and an output line (24) for coupling the first and second output electrical signals to, respectively, second and third ports comprising, respectively, a first output port (26) and a second output port (28), the output line (24) having a junction with the slotline (18); wherein the slotline (18) couples the input electrical signal to the junction, and the junction acts as a divider to produce the first and second electrical signals; wherein the hybrid coupler further comprises: an input section including said input line (14) and an output section including said output line (24), and wherein the slotline (18) is terminated at the output section by an output open circuit termination (22); a pair of ground planes, between which said input line (14) and said output line (24) are located; and wherein: on one of the ground planes, the slotline (18) transitions at said output section into a first end of a Co-Planar Waveguide (40), said Co-Planar Waveguide (40) being electrically connected to said output line (24), said Co-Planar Waveguide (40) defining, at a second, opposing end thereof, a sum port (46) configured to divert common mode signals received at said first and second output ports (26) to said sum port (46).