An ablation catheter, comprising: - an elongated, flexible, tubular body member having a proximal end, a distal end, and a lumen extending between the proximal and distal ends; - a control shaft coaxially disposed and slidingly received within the lumen of the tubular body member; - a flexible carrier assembly coupled to the control shaft, having a plurality of ablation elements which can deliver electrical energy to tissue in a combination monopolar and bipolar mode, - wherein the carrier assembly includes a plurality of carrier arms, each arm having a proximal arm segment and a distal arm segment, - wherein a proximal end of the proximal segment and the distal end of the distal segment are attached to the control shaft by a coupler; - wherein retraction of the control shaft causes the carrier assembly to be constrained within the lumen of the tubular body member; and - wherein advancement of the control shaft causes the carrier assembly to extend beyond the distal end of the tubular body member and resiliently expand to a pre-determined shape; characterised in that - the proximal arm segment and the distal arm segment are connected by a resiliently flexible carrier arm bend portion for rotatably joining the distal arm segment to the proximal arm segment; and - wherein, on advancement, each proximal arm segment resiliently bends radially outwardly from coupler, while each distal arm segment bends radially inwardly from the bend point toward the longitudinally axis of the tubular body member, such that the ablation elements attached to the carrier arms are in a linear arrangement for forming a linear lesion. - an elongated, flexible, tubular body member having a proximal end, a distal end, and a lumen extending between the proximal and distal ends; - a control shaft coaxially disposed and slidingly received within the lumen of the tubular body member; - a flexible carrier assembly coupled to the control shaft, having a plurality of ablation elements which can deliver electrical energy to tissue in a combination monopolar and bipolar mode, - wherein the carrier assembly includes a plurality of carrier arms, each arm having a proximal arm segment and a distal arm segment, - wherein a proximal end of the proximal segment and the distal end of the distal segment are attached to the control shaft by a coupler; - wherein retraction of the control shaft causes the carrier assembly to be constrained within the lumen of the tubular body member; and - wherein advancement of the control shaft causes the carrier assembly to extend beyond the distal end of the tubular body member and resiliently expand to a pre-determined shape; characterised in that - the proximal arm segment and the distal arm segment are connected by a resiliently flexible carrier arm bend portion for rotatably joining the distal arm segment to the proximal arm segment; and - wherein, on advancement, each proximal arm segment resiliently bends radially outwardly from coupler, while each distal arm segment bends radially inwardly from the bend point toward the longitudinally axis of the tubular body member, such that the ablation elements attached to the carrier arms are in a linear arrangement for forming a linear lesion.