High-Q and miniaturized complementary split ring resonator-loaded substrate integrated waveguide microwave sensor for crack detection in metallic materials

•A microwave sensor detects crack in metallic materials.•Sensitivity is improved by loading the CSRR on the SIW.•The resonant frequencies of the microwave sensor are changed depending on both the width and the depth of the crack in metallic materials.

In this paper, a high-Q and miniaturized complementary split ring resonator (CSRR)-loaded substrate integrated waveguide (SIW) microwave sensor for the detection of cracks in metallic materials is presented. A SIW and CSRR with a high Q are used for achieving high sensitivity. In addition, by loading the CSRR on the SIW, the sensor is miniaturized and can be operated below the cut-off frequency of the SIW. The proposed sensor exhibits a frequency shift of 220 MHz for a 100-μm crack and 600 MHz for a 1-mm crack.

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