Waveguide Probe Loaded With Split-ring Resonators For Microwave Surface Detection

In Aeronautics and Astronautics field, external metal components are often exposed in harsh environment. These devices are prone to defects due to corrosion and aging, which are always so tiny or even covered by coating at the beginning of their appearance that it is very hard for detection by eye or conventional means. If these defects cannot be found in time and repaired. It may cause huge disasters and become undoubtedly serious threat to the safety of China's aerospace industry. Compared with other detection methods, microwave nondestructive testing technology has a lot of advantages, such as strong penetrating, testing small defects and even those hidden in coating quickly and reliably. Thus microwave nondestructive testing technology can be competent for these metal parts surface defect detection.This paper introduces a waveguide type microwave surface detecting probe which working in Ku band and loaded by Split-ring resonator(SRR).The probe consists of a rectangular waveguide loaded(WR62) with SRR array medium plate, using for the detection of metal surface and the crack hidden in the paint insulating medium below. SRR is a sub-wavelength structure, and can gather high electromagnetic energy in a small area. This feature can effectively improve the detection resolution. In this paper, the resonance principle and characteristics of SRR are studied, and the method for achieving SRR minimization is found by collaborative simulation of MATLAB and HFSS. Then we research on the detection performance of this SRR loaded waveguide microwave surface detection probe, using MATLAB programming, we control the vector network analyzer and scanning test frame to precise scanning and data acquisition. There are two improvements of the SRR loaded microwave surface detection probe: In order to improve the resolution, we design a new waveguide probe based on SRR minimization; In order to reduce adverse effect caused by the distance between probe and sample surface, we design a probe can that can contact the sample surface directly.In this paper, we proposed the method of realizing SRR minimization and the method to improve the resolution of the probe. These researches have important significance to the development of microwave nondestructive testing technology.