A driving circuit outputs an output voltage as a driving signal to the gate of a semiconductor element based on a control signal given from an input circuit. The first and second cables are threadedly secured to the male and female couplings respectively. The covering may be on the exterior surface of the stent, or on the interior surface of the stent, or both. Finally, the first communication device andor the second communication device utilize one or more band-edge channels for transmitting a relatively reduced power level.