摘要：Effective complex permittivity measurements of materials are important in microwave engineering and microwave chemistry. The BP (Back Propagation) neural network computational module has been applied to microwave technology and becomes a useful tool recently. A neural network can be trained to learn the behavior of an effective complex permittivity of material under microwave irradiation in an experimental system. It can provide a fast and accurate result for the material permittivity. Thus, the on-line measurement has been realized. In this paper, a measurement system has been designed and the S-parameters are obtained by full-wave simulations to reconstruct the material permittivity. Moreover, several organic solvents have been measured. The relative errors of the reconstructed results for several organic solvents are less than 5% compared with reference data. The reconstructed results of the effective permittivities of solvents by means of the BP neural network are obtained quickly and accurately.
