Deterministic propagation model for RFID using site-specific and FDTD Marcelo Cunha de Azambuja a , Fabiano Passuelo Hessel a , Everton Luís Berz a *, Leandro Bauermann Porfírio a , Paula Ruhnke Valério b , Suely De Pieri Baladei c and Carlos Fernando Jung d a Faculty of Informatics and Computer Science, PUCRS University, Porto Alegre, Brazil; b Flextronics Instituto de Tecnologia, RFID Center of Excellence, São Paulo, Brazil; c T-Systems do Brasil Ltda, São Paulo, Brazil; d Integrated Faculties of Taquara – FACCAT, Taquara, Brazil (Received 15 December 2012; accepted 5 January 2014) The conduction of experiments to evaluate a tag orientation and its readability in a laboratory offers great potential for reducing time and costs for users. This article presents a novel methodology for developing simulation models for RFID (radio- frequency identification) environments. The main challenges in adopting this model are: (1) to find out how the properties of each one of the materials, on which the tag is applied, influence the read range and to determine the necessary power for tag reading and (2) to find out the power of the backscattered signal received by the tag when energised by the RF wave transmitted by the reader. The validation tests, performed in four different kinds of environments, with tags applied to six different kinds of materials, six different distances and with a reader configured with three different powers, showed achievements on the average of 95.3% accuracy in the best scenario and 87.0% in the worst scenario. The methodology can be easily duplicated to generate simulation models to other different RFID environments. Keywords: RFID; RFID environment simulation; RF propagation model; RFID validation; FDTD Introduction RF (radio-frequency) models have been an object of study for quite some time, and several methods have been used to build these models. The scientific methodology divides the models into statistical and deterministic (like site-specific and finite-difference time- domain – FDTD) simulation models (Sarkar, Zhong Ji, Kyungjung Kim, Medouri, & Salazar-Palma, 2003). It was necessary to use the two mentioned deterministic methods – site specific and FDTD – to create the model presented in this work, which can be easily duplicated to other situations and environments. Besides the usual environmental problems faced in RF simulations, such as scattering by obstacles, noise and reflections, RFID (radio-frequency identification) systems also present the particularity of very low-power signal emitted by the passive UHF RFID tags (Nikitin & Rao, 2006a, 2008). To calculate the reverse channel (the echo back from the tag to the reader), it is fundamental to know the ratio of power returning from the tag when this is reached by the reader RF signal. Also, to identify how the tag’ s behaviour changes according to the material to which it is attached, a series of tests, presented in the *Corresponding author. Email: everton.berz@acad.pucrs.br International Journal of Electronics, 2015 Vol. 102, No. 6, 932–945, http://dx.doi.org/10.1080/00207217.2014.945192 © 2014 Taylor & Francis