An integrated electrode structure comprising: a catheter shaft (107, 824) comprising a proximal end and a distal end, the catheter shaft (107, 824) defining a catheter shaft longitudinal axis (aa, a'a'); a flexible tip portion (110, 500, 540, 660, 700, 740, 780, 822) located adjacent to the distal end of the catheter shaft (107, 824) and adapted to conform to a tissue, the flexible tip portion (110, 500, 540, 660, 700, 740, 780, 822) comprising a flexible framework formed from a planar substrate; a first inboard arm (104, 164, 230, 310, 506, 554, 670, 708), second inboard arm (105, 165, 231, 311, 508, 546, 672, 710), first outboard arm (103, 164, 312, 504, 542, 582, 706), and second outboard arm (106, 313, 510, 548, 588, 674, 712), each of the first and second inboard and outboard arms defining a planar top surface and a planar bottom surface, the bottom surface being parallel with the top surface; and a first planar array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) patterned onto each of the top surfaces of the inboard and outboard arms and a second planar array (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) of microelectrodes patterned onto each of the bottom surfaces of the inboard and outboard arms; wherein the first array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) is parallel with the second array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3). a catheter shaft (107, 824) comprising a proximal end and a distal end, the catheter shaft (107, 824) defining a catheter shaft longitudinal axis (aa, a'a'); a flexible tip portion (110, 500, 540, 660, 700, 740, 780, 822) located adjacent to the distal end of the catheter shaft (107, 824) and adapted to conform to a tissue, the flexible tip portion (110, 500, 540, 660, 700, 740, 780, 822) comprising a flexible framework formed from a planar substrate; a first inboard arm (104, 164, 230, 310, 506, 554, 670, 708), second inboard arm (105, 165, 231, 311, 508, 546, 672, 710), first outboard arm (103, 164, 312, 504, 542, 582, 706), and second outboard arm (106, 313, 510, 548, 588, 674, 712), each of the first and second inboard and outboard arms defining a planar top surface and a planar bottom surface, the bottom surface being parallel with the top surface; and a first planar array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) patterned onto each of the top surfaces of the inboard and outboard arms and a second planar array (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) of microelectrodes patterned onto each of the bottom surfaces of the inboard and outboard arms; a flexible framework formed from a planar substrate; a first inboard arm (104, 164, 230, 310, 506, 554, 670, 708), second inboard arm (105, 165, 231, 311, 508, 546, 672, 710), first outboard arm (103, 164, 312, 504, 542, 582, 706), and second outboard arm (106, 313, 510, 548, 588, 674, 712), each of the first and second inboard and outboard arms defining a planar top surface and a planar bottom surface, the bottom surface being parallel with the top surface; and a first planar array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) patterned onto each of the top surfaces of the inboard and outboard arms and a second planar array (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) of microelectrodes patterned onto each of the bottom surfaces of the inboard and outboard arms; wherein the first array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3) is parallel with the second array of microelectrodes (102, 146-1, 146-2, 146-3, 163-1, 163-2, 163-3).