Abstract: A waveguide busbar for converting a plurality of high-frequency input signals into high-frequency output signals, includes a waveguide, a plurality of input ports, which are arranged along the waveguide, such that each input port is intended to receive a high-frequency input signal, an output port on the waveguide for delivering the high-frequency output signal and at least one parallel resonator, which is connected to the waveguide busbar between two input ports. The parallel resonator has a mechanically adjustable volume with which a phase relation of the waveguide is adjustable between the two input ports.