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Equations (2.1.79) of chapter 2 provide the voltage and current waves on a transmission line:

The V⁺ and V⁻ are the amplitudes of the forward and reflected waves, respectively. For convenience, the distance x is measured from the port‐2. The voltage and current at the port‐2 are

The amplitudes of the forward and reflected voltages in terms of the port voltage and port current are

The voltage and current on a transmission line can be written as

The voltage and current at the input port‐1 are obtained for x = −ℓ:

Above equations can be written in the matrix form:

The [ABCD] parameters of the lossy and lossless transmission line sections are given by equation (3.1.25a) and equation (3.1.25b), respectively:

(3.1.25)

The above example can be further extended to a network of several cascaded transmission line sections having different ℓ, Z₀, and γ. The overall [ABCD] parameter of the multisection transmission line can be obtained by a multiplication of the [ABCD] matrix of each line section. The line sections can be attached to the series and the shunt lumped elements. Even in such cases, one can find the overall [ABCD] parameter of a complete network. The input impedance, output impedance, Thevenin and Norton equivalent circuits, and power transfer relation, etc. of a complete circuit can be written in terms of the [ABCD] matrix. However, a detailed discussion of these aspects is out of the scope of this book. The reader can follow many available texts for this purpose [B.1, B.2–B.5, B.7, B.8].