Material characteristic complex dielectric constant inversion method based on two-port S parameter

The invention discloses a material characteristic complex dielectric constant inversion method based on two-port S parameters, which comprises the following steps: firstly, obtaining two-port S parameters S11 and S21 of a measured medium, then carrying out unwrapping processing on the phase of the S21 parameter to enable the S21 parameter to be a monotonically increasing or decreasing curve, calculating the slope of the S21 parameter, and estimating an initial complex dielectric constant according to the slope; calculating a transmission coefficient T by using the parameter S11 and the parameter S21, and determining an error function F (epsilon r) according to the transmission coefficient T and the reflection coefficient R; finally, using an estimated complex dielectric constant obtained by using the parameter S21 as an initial value, and changing the complex dielectric constant by using a Newton method to enable an error function F (epsilon r) lt; and 10 to 5 parts. According to the method, the problems of m