Enhanced surface acoustic wave biosensor performance via delay path modifications in mutually interacting multidirectional transducer configuration: A computational study

Abstract

Multidirectional interdigital transducers (IDTs) combined with delay path modifications for surface acoustic wave (SAW) sensors in a Langasite substrate are shown to positively and significantly impact power consumption, device sensitivity, and biofouling elimination capability. Simulated devices have mutually interacting orthogonal IDTs and microcavities of square cross sections of side λ/2, and of different depths located in the middle of the delay path. A combined orthogonal IDT-polystyrene filled microcavities device (dimensions λ/2×λ/2×λ/2), with constructive wave interference and enhanced SAW entrapment in the delay region, is shown to be most efficient and reduces insertion loss by 23.6 dB, generates two orders of magnitude larger streaming forces, and exhibits velocity sensitivity 100% larger than that of a simulated standard SAW sensor with unidirectional IDTs along the (0, 22, 90) direction.