A waveguide-to-parallel-plate twist transition, comprising: at least two integrally-formed waveguide-to-parallel plate twist transition elements arranged adjacent to each other in a linear array, the at least two integrally-formed waveguide-to-parallel plate twist transition elements including i) an input port having an input waveguide portion, the input waveguide portion configured to orient an E-field of an electromagnetic wave along a first plane; ii) an output port comprising a multi-mode parallel plate transmission line portion, the multi-mode parallel plate transmission line portion configured to orient an E-field of an electromagnetic wave along a second plane, wherein an angle of orientation of the second plane is different from an angle of orientation of the first plane; and iii) at least one intermediate discrete twist waveguide stage coupling the input waveguide portion to the multi-mode parallel plate transmission line portion, wherein the at least one intermediate discrete twist waveguide stage is configured to orient an E-field of an electromagnetic wave along a third plane, wherein an angle of orientation of the third plane is between the angle of orientation of the first plane and the angle of orientation of the second plane, wherein the waveguide to parallel plate twist transition is formed in a plate structure comprising a first plate portion and a second plate portion removably attachable to the first plate portion, and wherein a first portion of the input port, a first portion of the output port and a first portion of the at least one intermediate discrete twist waveguide stage are each formed in the first plate structure, and a second portion of the input port, a second portion of the output port and a second portion of the at least one intermediate discrete twist waveguide stage are each formed in the second plate structure. at least two integrally-formed waveguide-to-parallel plate twist transition elements arranged adjacent to each other in a linear array, the at least two integrally-formed waveguide-to-parallel plate twist transition elements including i) an input port having an input waveguide portion, the input waveguide portion configured to orient an E-field of an electromagnetic wave along a first plane; ii) an output port comprising a multi-mode parallel plate transmission line portion, the multi-mode parallel plate transmission line portion configured to orient an E-field of an electromagnetic wave along a second plane, wherein an angle of orientation of the second plane is different from an angle of orientation of the first plane; and iii) at least one intermediate discrete twist waveguide stage coupling the input waveguide portion to the multi-mode parallel plate transmission line portion, wherein the at least one intermediate discrete twist waveguide stage is configured to orient an E-field of an electromagnetic wave along a third plane, wherein an angle of orientation of the third plane is between the angle of orientation of the first plane and the angle of orientation of the second plane, i) an input port having an input waveguide portion, the input waveguide portion configured to orient an E-field of an electromagnetic wave along a first plane; ii) an output port comprising a multi-mode parallel plate transmission line portion, the multi-mode parallel plate transmission line portion configured to orient an E-field of an electromagnetic wave along a second plane, wherein an angle of orientation of the second plane is different from an angle of orientation of the first plane; and iii) at least one intermediate discrete twist waveguide stage coupling the input waveguide portion to the multi-mode parallel plate transmission line portion, wherein the at least one intermediate discrete twist waveguide stage is configured to orient an E-field of an electromagnetic wave along a third plane, wherein an angle of orientation of the third plane is between the angle of orientation of the first plane and the angle of orientation of the second plane, wherein the waveguide to parallel plate twist transition is formed in a plate structure comprising a first plate portion and a second plate portion removably attachable to the first plate portion, and wherein a first portion of the input port, a first portion of the output port and a first portion of the at least one intermediate discrete twist waveguide stage are each formed in the first plate structure, and a second portion of the input port, a second portion of the output port and a second portion of the at least one intermediate discrete twist waveguide stage are each formed in the second plate structure.