Katmanlı piezoelektrik yüzey akustik dalga sensörlerin hesaplamalı dinamik analizi

Surface acoustic waves (SAWs) actuated by the inter-digital-transducers (IDT) on piezoelectric substrates are used in sensor technology. The configurations of IDT are resonator or delay-line, for which the responses show different dynamics. When a thin film is sputtered on the substrate/IDT combination, Love SAW mode is observed depending on the material selection. In this thesis we focus on Love SAW mode, which is mechanically feasible for detecting chemical agents in liquid environments. The manufacturing of these sensors should be done under very expensive equipment and meticulous operation. Setting the experimentation setup for testing also affects the microelectronic device reliability of the manufactured sensors due to pyroelectricity of the substrates. While testing, melting of the IDT material may occur due to high resistivity at some local regions. Not only that, but also the assessment of the dynamics of the waves requires specialized instruments, which might be inaccessible. Under these circumstances a robust computational workflow of the sensors might ease the overhead, and give invaluable data that can be achieved by just using a computer. Under this context, a computational analysis guideline is proposed using libre and open-source software. The goal of the guideline is to generate data to be analyzed towards making a reliable sensor device under given some design constraints. The responses of both IDT configurations shows different dynamics, yet the measure of success is set to an optimum layer thickness which gives an optimum mass sensitivity for both of them. Development of the guideline is started with modeling a simple thickness-shear mode problem. Developed FEniCS code is applied to reveal dispersive characteristics of a sensor through EVP results used in a postulated mass sensitivity calculation. Computed eigenfrequencies show close agreement with the experimental resonance frequencies. An optimum thickness is obtained to be used in transient solution for both the RVE and mock-up sensor geometry to analyse the displacements and electrical potential variables.