Some Remarks on Positive Real Functions and Their Circuit Applications

In this paper, a boundary version of the Schwarz lemma has been considered for driving point impedance functions at s=0 point of the imaginary axis. Accordingly, under Z(0)=0condition, the modulus of the derivative of the Z(s) function has been considered from below. Here, Z(alfa), c1 and c2 coefficients of the Taylor expansion of the Z(s)=beta+c1(s-alfa)+... function have been used in the obtained inequalities. The sharpness of these inequalities has also been proved