Fast FEM/BEM Simulation of non-periodic SAW structures

This paper proposes two methods to reduce the time cost of BEM (Boundary Element Method) and FEM (Finite Element Method). In BEM, approximating Green´s function by exponential terms IS proposed, which can precisely derive the coefficients of exponential terms. Its theory is that, according to each exponential term has a different contribution regions in spatial domain for Green´s function, coefficients of one exponential term can be extracted in each region by mathematical fitting procedure. In FEM, approximating the equations´ coefficients by poles is proposed to omit the large time cost for equations solution. The response of a SAW (Surface Acoustic Wave) RFID (Radio Frequency Identification Tag) structure is calculated by FEMIBEM with two different methods. One is the former FEMIBEM before this work that uses approximating Green´s function by pIece-WIse polynomials in BEM and the traditional FEM. The other is using the two methods proposed in this work. Comparing the calculated response demonstrates that the FEMIBEM using the two methods in this work accelerates by an order of magnitude with the almost same precision, compared with the former FEMIBEM.