Finite Element Evaluation of Surface Acoustic Wave Reflection and Scattering from Topographic Irregularities Comparable with the WavelengthS. Yankin[1,2], S. Suchkov, S. Nikitov[2,3], B. Sveshnikov, I. Shatrova 
Joint International Laboratory LICS/LEMAC, IEMN UMR CNRS 8520, EC Lille,Villeneuve d’Ascq, France
Saratov State University, Saratov, Russia
Institute of Radio-engineering and Electronics, Russian academy of Science, Moscow, Russia
Design of SAW devices needs the accurate study of the scattering fields, arising from the interaction of SAW with topographic irregularities. To solve this problem FE methods very perspective, because with its help one can take into account the actual geometry of the electrodes and reflectors. This work describes results of original time domain calculation of 2D SAW scattering fields in delay line made on 128°YX LiNbO3 substrate. Reflection, transmission and scattering coefficients are numerically evaluated as functions of the reflector’s thickness. Calculations of SAW scattering field's picture clearly show that the intense SAW energy scattering into volume occurs for certain parameters of the reflectors, while for some other configuration SAW pass through irregularities practically without scattering.