a coaxial mirror is provided for reflecting an electromagnetic signal . the mirror includes an outer pipe , an inner pipe , and first and second rods . the outer pipe extends between input and output ports , with closed initial and final terminals disposed at their respective ports . the inner pipe extends between a closed fore end and an open aft end . the inner pipe is coaxially disposed between the initial and final terminals within the outer pipe . the first rod , coaxially disposed within the outer pipe , extends from the input port to the fore end . the second rod , coaxially disposed within the inner pipe , extends from downstream of the fore end to the output port . preferably , the first and second pipes are cylindrical tubes . preferably , fluoropolymer fills the annular region between the inner and outer pipes , and fluoropolymer foam fills the inner pipe . preferably , the first pipe has an electrically conductive inner surface , the second pipe has electrically conductive inner and outer surfaces , and the first and second rods have conductive surfaces . a first embodiment includes a conductor , coaxially disposed within the inner pipe , that extends from the fore end to the second rod . in a second embodiment , the second rod is hollow , and is preferably filled with the foam .