OPEN RESONATOR METHOD FOR THE NONDESTRUCTIVE TEST OF DIELECTRIC MATERIALS AT MICROWAVE FREQUENCY
Zhou Liping, Xu Deming*, and Li Zhaoning* Department of Mechanical Engineering East China University of Science and Technology, Shanghai, 200237, China *Department of Electronics, Shanghai University, Shanghai, 201800, China
Keywords: Nondestructive testing, dielectric material, permitivity, open resonator, microwave
ABSTRACT
A novel microwave nondestructive testing method is described in this paper. This technique uses a hemispherical type open resonator to test dielectric materials. The principle of the open resonator method is explained, an apparatus of this kind designed for working at 8 mm waveband is described and its photo is also shown in the paper. The complex permitivity of dielectric slabs can be measured accurately with this apparatus, and other properties of the materials under test, which have relations with permitivity, can be investigated and determined nondestructively by this approach. The experiments with this apparatus on a series of plate shaped samples have been made by the authors. The block diagram of testing system, the experimental procedures, and some experiment results are reported here. Making a little modification on the apparatus, this hemispherical type open resonator can also be used to make nondestructive test on liquid or pasted dielectric materials, and dielectric slabs backed by conducting plates. The method reported here has the advantages that:
sample need not to be prepared elaborately;
sample can be loaded onto and withdrawn from the apparatus conveniently; and
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 3, pages 1551 - 1554 Publisher:Ashgate Publishing Company
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