Since last decades, microwaves have received tremendous attention as an interesting tool for material characterization. In general, standard microwave measurement methods require cutting and polishing of samples to put it in a suitable waveguide or cavity. However, several methods have been developed in order to permit a non-destructive measurement. A well-known method is based on coaxial open-ended waveguide, which is used as a sensor for dielectric characterizations. Moreover, with the requirement of new forms, developing mathematical model for each one is not convenient. Indeed, the complex structures required in the industrial field can be perfectly designed with high-performance three-dimensional software. Many attempts have been done to solve the conversion problem by proposing different algorithms. Nevertheless, they are sensitive for complex structure that contains transition part. In this paper, we propose a dielectric measurement method based on the use of coaxial waveguide. A novel algorithm for dielectric characterization of complex structures is also presented, which is based on the joint use of artificial neuronal networks and finite element method. The proposed algorithm aims to find the dielectric characterization for complex structures. Experimental evaluations applied to solid and liquid dielectrics confirm the validation of the proposed algorithm.

The tomatoes production shows a fast growing in the word. The need of fast industrial process to covert the high request of the second more consumed vegetarian produced after the potatoes, have attracted a considerable interest from both academia and industry. In this article, we develop a model based on high frequency structural simulator (HFSS) to evaluate different armatures of tomatoes for real time monitoring process. Unlike previous techniques, based on image processing, the proposed study presents a new approach of tomatoes evaluation. The tomatoes color may differ from side to another, which limits such solution. The proposed system uses the microwave penetration capability in order to perform 3D tomatoes evaluation. The sensitive of dielectric variation in terms of liquids composite of tomatoes, presents a new criteria for ripeness classification. The proposed model is simulated and experimentally approved for different kinds of tomatoes samples. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2901–2905, 2016