The rotary phase shift device includes an electrically conductive track (7), including a plurality of concentric segments (7a-7f) around an axis X-X', placed in a matrix (8) of low dielectric constant, at least one part (5, 6) in sliding contact with the track (7) of a material having a dielectric constant higher than that of the matrix, and adapted to be moved in rotation about the axis X-X' relative to the track (7), and at least one conductive surface (2, 3) disposed in contact with the exterior face of the dielectric part (5, 6).
According to the invention, the track (7) includes a number Ne of input ports (31), each input port (31) being common to at least two segments (7a-7f), and a number Ns of output ports (32, 33), each of the segments (7a-7f) having an output port (32, 33), so that Ne is less than Ns. The device further comprises impedance transformation means (42) and means (43) for splitting the power between the segments (7a-7f).