DIELECTRIC PARAMETERS OF DYED COTTON FABRICS
Keywords:
Capacitive ECG electrode, dye, fabric dielectrics, capacitance, relative permittivity.Abstract
Non-contact electrodes have capacities in long-term monitoring of electrocardiogram (ECG) and
early detection of heart abnormalities. In non-contact ECG sensing, the dielectric materials
strongly influence the effectiveness of the electrodes. Over the past three decades, there has been
extensive research on fabric dielectrics because they are harmless, plentiful, comfortable, and
skin conformable. A high and stable permittivity is essential in fabric dielectrics used in noncontact
electrodes. However, the dye used on fabrics can immensely influence their relative
permittivity and electrode coupling capacitance. This study investigates the effects of dye on
dielectric parameters of cotton fabrics using the parallel plate technique in dry and moisturized
conditions. The results show that undyed fabric has higher capacitance but lower relative
permittivity in dry and moisturized conditions. In contrast, dyed fabrics showed higher
permittivity, but slight differences were found depending on the dye used. These findings
demonstrate that dyed fabrics are more effective as dielectrics for capacitive ECG electrodes.
