A re-configurable magnetoinductive waveguide (300), comprising a plurality of resonator cells, wherein each resonator cell comprises a primary resonator (110) that is inductively coupled to a primaryresonator (110) of at least one other resonator cell, and wherein at least one of the plurality of resonator cells is a controllable cell (100) which further comprises a control element ( 120), the control element (120) having an active control component ( 125) that is operable to adjust the impedance of the primary resonator (110) of the controllable cell (100) in response to a control signal; wherein: the control element ( 120) comprises a secondary resonator, the secondary resonator is inductively coupled to the primary resonator (110), and the active control component (125) is arranged tovary the electrical properties of the secondary resonator in response to the control signal.