This proposes a model for a microwave heated fluidized bed by ceramic pellets to highlight the possibility to obtain a temperature gradient between the gas and the pellets. After a review of the recent work on microwave effects on chemical reactions, a short description of fluidization is given for a better understanding of the phenomena, followed by a development of a model of the heat transfer processes taking place in the fluidized bed. A parameter study describes the trends that should be expected despite the numerous restrictions and assumptions. Also, a set of parameters is proposed for optimal conditions that are close to the real conditions often encountered in practice. Numerous figures and tables are added, completing the main argument advanced in the thesis: it is possible to obtain a temperature difference between the gas and the pellets of a chemical bed reactor heated by microwaves by carefully choosing the following parameters: pellet diameter, bed height, gas velocity, pellet density and electric field.