Abstract: An apparatus that is a voltage-controlled splitting and/or switching apparatus comprising a waveguide for a radio frequency signal comprising at least one input and at least two outputs, wherein the waveguide is a cavity waveguide or a polymer microwave fiber waveguide, and the waveguide comprises at least a first branch and a second branch, at least one element comprising voltage reactive material in between electrodes and extending, at least partly, across at least one of the first branch and the second branch, and a voltage control caused to apply voltage to the at least one element.