The coupled lines of Figure 7.26, or other symmetric three-wire lines, can be represented by the structure and equivalent circuit shown in Figure 7.27. If we assume TEM prop-agation, then the electrical characteristics of the coupled lines can be completely deter-mined from the effective capacitances between the lines and the velocity of propagation on the line. As depicted in Figure 7.27,C12 represents the capacitance between the two strip conductors, andC11andC22represent the capacitance between one strip conductor