Research On Testing Technology Of Dielectric Properties Of Fiber Monofilament

Wave-transparent,stealth,shielding,and other functional composites made of monofilaments are widely used in some important fields,such as aerospace radomes,missile aircraft,radar satellites,and high-performance printed circuit boards(PCB).Monofilament is the basic raw material of these composites,and its dielectric properties will directly affect the properties of the composites.Therefore,it is of great significance to accurately test the dielectric properties of monofilament for the preparation and mechanism analysis of composites.Therefore,accurately testing the dielectric properties of monofilament is of great significance for the preparation and mechanism analysis of composites.Thesis mainly studies the testing technology of monofilament dielectric properties.After consulting the relevant research trends at home and abroad,it is known that the current characterization of the dielectric properties of monofilaments is mainly through indirect testing,that is,testing the equivalent dielectric constant of composites,and then inversely calculating the dielectric constant of monofilaments.However,the dielectric properties of monofilaments obtained by different indirect test methods are quite different.According to the relevant literature,there is no report on the direct test of the monofilaments’ dielectric properties.Therefore,the purpose of the thesis is to provide a test system,which can test the dielectric properties of monofilaments directly.In order to achieve the above purpose,a highly sensitive ridged semi-cylindrical resonant cavity is developed in the thesis.Based on the mode matching method,the field distribution of the resonant cavity is theoretically deduced,and then the simulation analysis of the resonant cavity is completed by the electromagnetic simulation software.After that,designing and building a system for the monofilament dielectric property test,the test software was written based on the theory of material perturbation to realize the automatic test of this system.Finally,by the monofilament dielectric properties test system built in the thesis,several monofilaments with different diameters were tested.The results of each monofilament are given,and the error sources in the test process are analyzed and summarized.Experiments show that the test system proposed in the thesis can directly test the dielectric properties of monofilament.Compared with the existing test methods,it can fundamentally characterize the dielectric properties of monofilament,and also save the cost and time of sample preparation.