FDTD numerical model for heating procedures in microwave multimode cavities MAGNO MEDEIROS DE ARAÚJO (1) , AUGUSTO CARLOS PAVÃO (2) , IDALMIR DE SOUSA QUEIROZ JR (2) , HUMBERTO DIONÍSIO DE ANDRADE (2) , ROMÊNIA GURGEL VIEIRA (2) (1) Federal Institute of Education, Science and Technology Via Raimundo Firmino de Oliveira 400, Mossoró, 50625-216, RN BRAZIL magno.medeiros@ifrn.edu.br (2) Department of Environmental Sciences and Technology Federal Rural University of the Semi-Arid, Av. Francisco Mota 572, Mossoró, 59625-900, RN BRAZIL augusto.pavao@ufersa.edu.br, idalmir@ufersa.edu.br, humbertodionisio@ufersa.edu.br, romenia.vieira@ufersa.edu.br Abstract: - This work aims to develop a numeric model using FDTD in order relate the microwave spread, with the dielectric material heating on industry applications, standing as a base to future development of a software, which can study the microwave effects on these applications. Initially the basic issues involving the propagation of electromagnetic waves are discussed, as well as the equation that govern it. Then the mathematical treatment is performed, in order to related the known parameters to those obtained on the simulation. Lastly, experiments based in the simulated medium were performed, for the purpose of verify the error presented on the developed model. Those experiments allowed to conclude that the results numerically given, serve as a reference to situations where high precision is not necessary on the final temperature of the dielectric medium. Key-Words: - Microwave, Microwave Heating, Finite Difference Time Domain, Numerical Method 1 Introduction The use of microwaves for heating began in World War II [1], a period that the study and research with radars were in evidence. Since then, the use and the scope of heating microwave increased carrying the technology to various sectors of society such as industry and medicine. The ease and speed of microwave heating as compared to conventional heating, allowed the development of methods for mineral processing, food and tissues [2], increasing the efficiency and quality of the final product. Microwave heating receive great prominence in the treatment of tumors by hyperthermia process and blood transfusion during the heating procedure [3]. Despite the various applications and advantages, the study of microwave heating still requires the volumetric analysis for heating behavior, due to the high computational requirements of processing and memory, in addition to the variation of intrinsic material properties that vary with the temperature, increasing the computational effort. The simulations and the experiments that will be made in this work will establish a method of analysis for industrial use, ignoring the variation of permittivity in order to verify the extent of the influence of this variation when comparing the experimental results with the simulations. 2 Microwave Heating The heating using electromagnetic waves has been widely used in various branches of industry and medicine. The most common applications of this method are dehydration and cooking foods, drying materials, acceleration of chemical reactions, treatment of cancer cells and polymer processing [4]. The rate of heat transfer and the reduced heating time are advantages of microwave heating. Moreover, the control during the process is simpler and faster than the conventional procedure, since it WSEAS TRANSACTIONS on COMMUNICATIONS Magno Medeiros De Araújo, Augusto Carlos Pavão, Idalmir de Sousa Queiroz Jr., Humberto Dionísio de Andrade, Romênia Gurgel Vieira E-ISSN: 2224-2864 353 Volume 16, 2017