An integrated electrode structure comprising: a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis (aa, a'a'); a flat flexible tip portion located distally with respect to the distal end of the catheter shaft , wherein the flat flexible tip portion comprises a flat flexible framework that consists of a plurality of arms that extend distally from the distal end of the catheter shaft ; a plurality of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) disposed on the flat flexible framework and forming a flexible planar array of microelectrodes adapted to conform to tissue; and a plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) disposed on the flat flexible framework , each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) electrically coupled with a respective one of the plurality of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3); a dielectric material (131, 166', 166") is disposed between each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) and the flexible framework ; and the dielectric material (131, 166', 166") covers an outer facing surface of each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3). a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis (aa, a'a'); a flat flexible tip portion located distally with respect to the distal end of the catheter shaft , wherein the flat flexible tip portion comprises a flat flexible framework that consists of a plurality of arms that extend distally from the distal end of the catheter shaft ; a plurality of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) disposed on the flat flexible framework and forming a flexible planar array of microelectrodes adapted to conform to tissue; and a plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) disposed on the flat flexible framework , each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) electrically coupled with a respective one of the plurality of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3); a dielectric material (131, 166', 166") is disposed between each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3) and the flexible framework ; and the dielectric material (131, 166', 166") covers an outer facing surface of each of the plurality of conductive traces (140-1, 140-2, 140-3, 162-1, 162-2, 162-3, 224-1, 224-2, 224-3, 372, 373, 388, 391, 518-1, 518-2, 518-3, 518-4, 636-1, 636-2, 636-3, 664, 750, 758-1, 758-2, 758-3). <EOS>