A rotary cathode assembly for a sputtering apparatus, the rotary cathode assembly comprising: a rotatable target cylinder (172, 210) having an inner surface that defines an interior passageway; and a magnetron assembly disposed inside the target cylinder (172, 210), the magnetron assembly comprising: a rigid support structure (102, 142) positioned within the interior passageway of the target cylinder; a magnet bar structure (104, 144) movably attached to the rigid support structure (102, 142) within the interior passageway; a plurality of actuation mechanisms (108, 146) coupled to the rigid support structure (102, 142) and configured to change a distance of the magnet bar structure (104, 144) from the inner surface of the target cylinder (172, 210); a plurality of position indicating mechanisms each associated with a respective one of the actuation mechanisms (108, 146) and operative to measure a position of the magnet bar structure (104, 144) relative to the inner surface of the target cylinder (172, 210); and an electronic controller in the target cylinder (172, 210) and in operative communication with the actuation mechanisms (108, 146); the rotary cathode assembly further comprising: a first transceiver located in the target cylinder (172, 210) and operatively coupled to the electronic controller; and a second transceiver located outside of the target cylinder (172, 210) and in signal communication with the first transceiver; wherein the actuation mechanisms (108, 146) are operable to adjust the position of the magnet bar structure (104, 144) with respect to the inner surface of the target cylinder (172, 210) in response to control signals from the electronic controller, as the target cylinder (172, 210) erodes during operation of the sputtering apparatus; characterised in that the rotary cathode assembly further comprises a power source (119, 160) fully self-contained within the volume of the magnetron assembly and coupled to the electronic controller and configured to supply energy to the actuation mechanisms (108, 146). a rotatable target cylinder (172, 210) having an inner surface that defines an interior passageway; and a magnetron assembly disposed inside the target cylinder (172, 210), the magnetron assembly comprising: a rigid support structure (102, 142) positioned within the interior passageway of the target cylinder; a magnet bar structure (104, 144) movably attached to the rigid support structure (102, 142) within the interior passageway; a plurality of actuation mechanisms (108, 146) coupled to the rigid support structure (102, 142) and configured to change a distance of the magnet bar structure (104, 144) from the inner surface of the target cylinder (172, 210); a plurality of position indicating mechanisms each associated with a respective one of the actuation mechanisms (108, 146) and operative to measure a position of the magnet bar structure (104, 144) relative to the inner surface of the target cylinder (172, 210); and an electronic controller in the target cylinder (172, 210) and in operative communication with the actuation mechanisms (108, 146); the rotary cathode assembly further comprising: a rigid support structure (102, 142) positioned within the interior passageway of the target cylinder; a magnet bar structure (104, 144) movably attached to the rigid support structure (102, 142) within the interior passageway; a plurality of actuation mechanisms (108, 146) coupled to the rigid support structure (102, 142) and configured to change a distance of the magnet bar structure (104, 144) from the inner surface of the target cylinder (172, 210); a plurality of position indicating mechanisms each associated with a respective one of the actuation mechanisms (108, 146) and operative to measure a position of the magnet bar structure (104, 144) relative to the inner surface of the target cylinder (172, 210); and an electronic controller in the target cylinder (172, 210) and in operative communication with the actuation mechanisms (108, 146); the rotary cathode assembly further comprising: a first transceiver located in the target cylinder (172, 210) and operatively coupled to the electronic controller; and a second transceiver located outside of the target cylinder (172, 210) and in signal communication with the first transceiver; wherein the actuation mechanisms (108, 146) are operable to adjust the position of the magnet bar structure (104, 144) with respect to the inner surface of the target cylinder (172, 210) in response to control signals from the electronic controller, as the target cylinder (172, 210) erodes during operation of the sputtering apparatus; characterised in that the rotary cathode assembly further comprises a power source (119, 160) fully self-contained within the volume of the magnetron assembly and coupled to the electronic controller and configured to supply energy to the actuation mechanisms (108, 146).