Optimisation of interdigitated electrodes for piezoelectric actuators and active fibre composites

The optimisation of the interdigitated electrode (IDE) design for active fibre composites was performed using finite element analysis. The effect of the IDE geometry (electrode width and spacing) and electroceramic substrate thickness on the developed strain for bulk PZT substrates was modelled. The modelling results show that the highest strain is generated when the electrode width equals half the substrate thickness and for thin substrates the electrode finger spacing can be reduced to enable lower driving voltages. Approximately 80% of the maximum d33 strain can be achieved with an electrode separation to substrate thickness ratio greater than 4. The results present simple coherent guidelines for the optimisation of electrode geometry for piezoelectric actuators and active fibre composites.