the invention related to a method and circuit that is used to compensate for s - parameters of a passive circuit which do not satisfy passivity . the method includes the following steps : getting s - parameters which do not satisfy passivity , these s - parameters being composed of an s - parameter matrix s ; computing matrix , wherein matrix s ′ is a complex conjugate transposed matrix of the s - parameter matrix s ; computing the eigenvalues of the matrix , and choosing an eigenvalue ψ whose real part real is the biggest ; computing a compensating value ξ , the compensating value ξ being equal to real 1 / 2 ×, wherein the ε is a very small positive number ; and dividing each of the s - parameters by the compensating value ξ to get the compensated s - parameters .