Method of amplitude-phase inconsistency in-situ correction for the multi-channel capacitive sensor

A method of amplitude-phase inconsistency in-situ correction for a multi-channel capacitive sensor, comprising:

• S1:
• under a calibrating mode, inputting a calibration signal from a calibration capacitance network module to the multi-channel capacitive sensor, and measuring output complex voltages of the multi-channel capacitive sensor at each calibration frequency point;
• S2:
• equating the calibration capacitance network module to multi-channel three-admittance networks, measuring port scattering parameters of each equivalent three-admittance network, and extracting three-admittance parameters of each-channel at each calibration frequency point;
• S3:
• selecting any channel of the multi-channel capacitive sensor as a reference channel;
• calculating an amplitude-phase correction coefficient of each-channel relative to the reference channel through combining the three-admittance parameters of each-channel at each calibration frequency point and the output complex voltages of the multi-channel capacitive sensor at each calibration frequency point;
• S4:
• under an operating mode, inputting a carrier signal to the multi-channel capacitive sensor through a multiple degree of freedom (DoF) sensitive probe, and measuring the output complex voltages of the multi-channel capacitive sensor under actual operation;
• S5:
• multiplying the output complex voltages of the multi-channel capacitive sensor under actual operation by the amplitude-phase correction coefficients, thereby obtaining multiple sensing channel output signals after eliminating inter-channel amplitude-phase inconsistency,
• wherein the calibration capacitance network module comprises a one-to-multiple equal-amplitude in-phase power splitter and a multi-channel calibration capacitance network, and each channel of which comprises three capacitors with the same nominal value and connected in a Y-shaped manner, and two single-pole double-throw switches connected to the capacitors.