System and method for testing multi-frequency point material

Abstract

The invention discloses a system and method for testing a multi-frequency point material. By virtue of the advantage that a main mode of a coaxial opening type resonant cavity is not interfered by a parasitic mode, a dielectric constant of a tested material is calculated through the deviation of a resonant frequency point, and the rough position of the deviated resonant frequency point in a relatively high frequency band, so that the range of the testing frequency is extended. The method disclosed by the invention is suitable for measuring most materials and is particularly suitable for measuring the materials such as quartz, polytetrafluoroethylene, sapphires, corundum and ceramic with dielectric properties barely changed along the frequency.

Description

technical field [0001] The present disclosure relates to the technical field related to microwave measurement, and in particular, relates to a multi-frequency point material testing system and method. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] As an electromagnetic wave transmission medium, microwave materials have been widely used in various microwave fields, such as microwave circuits, communications, and radar stealth. The electromagnetic parameters of microwave materials completely determine the propagation characteristics of electromagnetic waves in it. Accurate understanding of electromagnetic parameter values ​​is essential for the application of microwave energy and various applications of materials in the microwave frequency range. The electromagnetic parameters of dielectric materials generally refer to the complex permit...

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Problems solved by technology

However, these two methods have some problems. For example, the transmission line method has low test accuracy, it is inconvenient to make samples, and the calibration accuracy is high; the resonant cavity method is based on the perturbation method. The principle of the resonant cavity method is to The material sample is placed in a closed or open resonant cavity, and the complex permittivity and complex permeability of the sample are determined according to the change of its resonant frequency and quality factor Q value before and after being placed, usually by placing the sample in the resonant cavity under an electric field The complex permittivity of the sample is measured at the minimum magnetic field and the maximum. The advantage of using the resonant cavity method to measure the dielectric properties of the material is that the test accuracy is high.

The disadvantage of measuring the dielectric properties of materials is that only point frequency tests can be performed, and due to the influence of mixed modes, there are few test frequency points available, and the measurable bandwidth is narrow, making it difficult to test high frequencies.

Moreover, the resonant cavity of the perturbation method is a cylindrical or rectangular hollow cavity structure, and the measurement must satisfy that the size of the sample to be measured is less than a few tenths of the cavity size, making the fixture size too small to be practical

The multi-frequency point test needs to be carried out in multiple resonant cavities working at different frequencies, which will greatly increase the test cost for metal resonant cavities, whether rectangular or circular. Electrical constant, unable to achieve multi-frequency point measurement

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