Measurement of paint and coating thickness on metallic plates using smart near field microwave sensor

A smart microwave sensor for non-destructive thickness measurement of paint and dielectric coating of metallic plates is presented. The sensor is based on low cost microstrip transmission line with a Complementary Split-Ring Resonator (CSRR) in the ground plan. The CSRR sensor experiences a frequency shift proportional to the thickness of a dielectric layer backed with metallic plate as described. Ideally, one would like the frequency shift to be related directly to a thickness reading (usually in mm or um). An artificial intelligent regression model was developed to automate the post processing of the measurements and achieve actual thickness data. This work presents simulation, measurements, and data post-processing of CSRR sensor operating on metallic plate with different coating thicknesses. The post-processing was performed using Support Victor Regression (SVR) algorithm on the transmission coefficients.