A capacitive touch sensor device comprising set of crossing X and Y electrodes whose crossing points form a two-dimensional array of nodes which define a touch sensitive area. As well as the main electrode spines which cross, referred to as zeroth order electrode branches, the electrodes have higher order branches, some of which interdigitate. By varying the dimensions of the electrode branches, such as width and length, the overall area of the X and Y electrodes can be varied relatively independently of each other. It is therefore possible to produce an electrode pattern in which the self capacitances of the X and Y electrodes have a certain ratio, e.g. unity, and thereby compensate for the aspect ratio of the touch sensitive area, and/or to have a certain absolute value, e.g. in order not to overload a touch-sensor controller to which the sensor is to be connected.