A feed network comprising: a first transmitter unit that comprises: a first branch having a first input port and a second branch having a second input port; a first integrated branch line coupler coupling the first branch (3 10B) and the second branch, the first integrated branch line coupler comprising: a first waveguide reject filter in the first branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the first waveguide reject filter is coupled to the first input port; a second waveguide reject filter in the second branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the second waveguide reject filter is coupled to the second input port; a first group of one or more couplers (314A, 314B, 314C) coupled between the inner face of the first waveguide reject filter and the inner face of the second waveguide reject filter; and a first group of one or more single-sided stubs (302B, 302D, 302F) protruding outwardly from the outer face of the first waveguide reject filter and a second group of one or more single-sided stubs (302A, 302C, 302E) protruding outwardly from the outer face of the second waveguide reject filter; and a core waveguide coupled to the first branch (3 10B) via the second end of the first waveguide reject filter and to the second branch via the second end of the second waveguide reject filter; wherein the first group of one or more couplers (314A, 314B, 314C) are coupled inwardly between locations of the first and second groups of one or more single-sided stubs (302A, 302B, 302C, 302D, 302E, 302F), and wherein the first transmitter unit is configured to receive a linearly polarized signal from one of the first input port or the second input port and to generate a circularly polarized signal in the core waveguide. a first branch having a first input port and a second branch having a second input port; a first integrated branch line coupler coupling the first branch (3 10B) and the second branch, the first integrated branch line coupler comprising: a first waveguide reject filter in the first branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the first waveguide reject filter is coupled to the first input port; a second waveguide reject filter in the second branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the second waveguide reject filter is coupled to the second input port; a first group of one or more couplers (314A, 314B, 314C) coupled between the inner face of the first waveguide reject filter and the inner face of the second waveguide reject filter; and a first group of one or more single-sided stubs (302B, 302D, 302F) protruding outwardly from the outer face of the first waveguide reject filter and a second group of one or more single-sided stubs (302A, 302C, 302E) protruding outwardly from the outer face of the second waveguide reject filter; and a core waveguide coupled to the first branch (3 10B) via the second end of the first waveguide reject filter and to the second branch via the second end of the second waveguide reject filter; wherein the first group of one or more couplers (314A, 314B, 314C) are coupled inwardly between locations of the first and second groups of one or more single-sided stubs (302A, 302B, 302C, 302D, 302E, 302F), and wherein the first transmitter unit is configured to receive a linearly polarized signal from one of the first input port or the second input port and to generate a circularly polarized signal in the core waveguide. a first waveguide reject filter in the first branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the first waveguide reject filter is coupled to the first input port; a second waveguide reject filter in the second branch comprising a first end and a second end and an outer face and an inner face, wherein the first end of the second waveguide reject filter is coupled to the second input port; a first group of one or more couplers (314A, 314B, 314C) coupled between the inner face of the first waveguide reject filter and the inner face of the second waveguide reject filter; and a first group of one or more single-sided stubs (302B, 302D, 302F) protruding outwardly from the outer face of the first waveguide reject filter and a second group of one or more single-sided stubs (302A, 302C, 302E) protruding outwardly from the outer face of the second waveguide reject filter; and a core waveguide coupled to the first branch (3 10B) via the second end of the first waveguide reject filter and to the second branch via the second end of the second waveguide reject filter; wherein the first group of one or more couplers (314A, 314B, 314C) are coupled inwardly between locations of the first and second groups of one or more single-sided stubs (302A, 302B, 302C, 302D, 302E, 302F), and wherein the first transmitter unit is configured to receive a linearly polarized signal from one of the first input port or the second input port and to generate a circularly polarized signal in the core waveguide.