Based On The Labview Complex Dielectric Constant Of The Medium Of Nondestructive Automatic Test Research

Today, as an important representative of the electronic science and technology of modern information, microwave technology develops rapidly. From the field of military electronics to microwave energy industrial applications and the field of Electrical Log, microwave technology has a wide range of applications. And with integration with other electronic technology, the breadth and depth of application of microwave technology is still expanding and enhanced. Extensive use of microwave dielectric materials is followed. For the microwave dielectric materials, many of its features depend on the complex permittivity of the material. Therefore, by measuring the complex permittivity of dielectric material, understanding of material properties has important theoretical value and significance.At present, for most of the complex permittivity measurement method, the sample needs to be processed into standard sample size and undermined the integrity. Therefore,dielectric materials urgently need non-destructive testing,especially in the application of microwave energy field.This test system is developed based on non-destructive testing of the microwave dielectric plate.Based on cavity perturbation method a915MHz automatic system for the complex permittivity nondestructive measurement of dielectric material with a cylindrical cavity is developed in the study and analyzing of literature at home and abroad.First of all,the media complex permittivity measurement method is reviewed.And then through the field structure analysis of cylindrical resonant cavity,a915MHz cylindrical cavity is designed.Then,according to the cylindrical resonant cavity perturbation method,different shaps media samples relative dielectric constant and dielectric loss tangent formula is derived.In the complex permittivity formula derivation, for the difficulties of integral calculation of large size and irregular sample, electromagnetic simulation software CST is used to be amended. Entire system with a graphical system design solutions, combined with the National Instruments (NI’s) LabVIEW software platform and hardware GPIB-USB-HS to complete automated testing tasks. The system software architecture uses a modular design concept, and the introduction of error-handling mechanism, so that the system has good stability. Repeated tests of the same and different samples showed good repeatability and high precision of the system. Now it has been delivered.