Design Of Metal Crack Detection Sensor Based On Microstrip Resonance Structur

The microstrip resonant metal crack detection sensor is a sensor that uses the metal plane to be measured as the ground plane of the microstrip structure.Compared with traditional sensors,the microstrip resonant sensor has the advantages of high sensitivity,small size,low cost,and easy measurement.In this paper,a variety of microstrip resonant metal crack detection sensors are studied,and the details are as follows:Aiming at the problem that the traditional regular rectangular patch sensor cannot detect the gap parallel to the electric field direction,that is,there is a detection blind area,a single-port metal crack detection sensor based on an improved rectangular patch structure is proposed.By opening a hole in the center of a regular rectangular patch,the structure achieves that two resonant frequencies are obtained on a resonant patch,and the electric field polarization directions of the two resonant frequencies are perpendicular to each other,thereby achieving the purpose of detecting metal cracks without blind areas.The actual experimental results show that the sensor can detect cracks of different widths on the metal plate,and the sensitivity in the two electric field polarization directions is 83MHz/0.2mm and114MHz/0.2mm,respectively.Considering that the mode purity of the single-port metal crack detection sensor at the two resonant frequencies is not high,which is not conducive to the determination of the gap angle,a dual-port sensor structure is proposed.The structure realizes that the electric field polarization directions at the two resonant frequencies are perpendicular to each other and has a higher mode purity by means of coupling and feeding of two ports,and achieves the purpose of judging the angle of the metal crack to a certain extent.The actual experimental results show that the sensor can detect cracks of different widths on the metal plate.The sensitivity of the two electric field polarization directions is 11MHz/0.2mm and 20MHz/0.2mm,and the change of the two resonance frequencies can be Judge the crack angle to a certain extent.In addition,in response to the sensor design requirements that can achieve high-precision positioning of metal cracks,a metal crack detection sensor structure based on an open resonant ring is proposed.By rationally designing the excitation mode of the split resonant ring,the structure makes the resonant frequency of the sensor correlate with the relative position of the metal crack,and realizes the positioning of the metal crack through the resonant frequency.The actual experimental results show that the sensor can scan and locate the cracks on the metal plate,and the positioning error is within 1mm.Finally,in view of the limited detection range of the metal crack detection sensor based on a single split resonant ring,an array sensor solution is proposed.By using a stepped open microstrip line to couple four open resonant rings at the same time,the resonant frequency of four open resonant rings of different sizes can be measured with one port,which can effectively increase the coverage area of the sensor without increasing the number of ports.the goal of.The actual experimental results show that the sensor can detect metal cracks with a coverage area four times that of a single split resonant ring sensor.