A flexible frame comprising an electrically conductive hollow cylindricalmetallic tube having a plurality of cuts along the longitudinal axis to form aplurality ofconductive wires. The wires are equally spaced apart circumferentially alongthelongitudinal axis of the tube by a gap to electrically isolate the wires. Afirst electrodeis mounted around the circumference of the frame along the longitudinal axisandattached to a first wire of the plurality of wires. A second electrode ismounted aroundthe circumference of the flexible frame along the longitudinal axis at apredetermineddistance from the first electrode and attached to a second wire. A non-conductivethermoplastic layer may be secured to the outer surface of the flexible framebetweenthe first and second electrodes to form an insulation layer between the firstand secondelectrodes.
