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.

Abstract: Methods and apparatuses for controlling radio resources of radio units in air-to-ground mobile communications systems that include at least an aircraft carrying a transceiver station and a ground basestation, apt to communicate with each other. The radio units are provided with beamforming and/or massive MEM antenna systems, and are controlled by the apparatuses using control data. The apparatuses are configured to receive flight data related to the aircraft, estimate a timed trajectory and a required data rate, as a function of the flight data. Then the apparatuses determine a sequence of control data for said antenna systems to form radio beams and/or connectivity spots directed towards said transceiver station, respectively to the ground basestation, while the allocated data rate is at least equal to the required data rate. The sequence of control data is then provided to respective antenna systems.