A switchless combiner includes a circuit having a delay line consisting of a constant-impedance transmission line and a device adapted to vary the electric length of said transmission line, the device including a metallic body with walls defining a cavity, the walls being interrupted to define a slot, the cavity and the slot extending along at least a portion of the length of the device, the cavity including a first portion having a first cross-section and a second portion having a second cross-section which is greater than the first cross-section, the second portion having a dielectric element with a cutout corresponding to the slot, the first and second portions extending in the longitudinal direction of the device and the transmission line being positioned, inside the first and second portion, in the cutout, the dielectric element occupying the cavity of the second portion, and having an element to translate the dielectric element on the circuit in the longitudinal direction of the device.