1.5 CIRCUIT PARAMETERS OF VARIOUS SIMPLE NETWORKS

In Section 1.4, we introduced the most commonly used circuit parameter definitions for microwave networks. In this section, we provide the circuit parameters of various basic networks that are frequently used in microwave engineering.

The studied networks in this section are simple TEM transmission line, T- network, and Pi-network. These simple networks are frequently used in filter circuits and modeling of passive microstrip elements. After providing the circuit parameters, we will also show mathematical derivations for ABCD-parameters for the sake of completeness. This will help the readers to derive the circuit parameters of other circuits that are not provided here. Circuit parameters of some of the most commonly used networks are summarized in Table 1.1.

Table 1.1: Circuit Parameters of Various Simple Networks

Network	Z- and Y-Parameters	ABCD-Parameters

1.5.1 TEM Transmission Line

In this section, we give the ABCD-parameters of a TEM transmission line characterized by a given length, characteristic impedance, and propagation constant. Voltage and current conventions that will be used for this purpose are depicted in Figure 1.19.

Figure 1.19: TEM transmission line and voltage and current conventions used in the ABCD-parameter derivations.

It was shown previously that the voltage and current on a TEM transmission line are given as follows:

where Z _c and ? are the characteristic impedance and complex propagation constant, respectively. To find the ABCD-parameters, we will evaluate voltages and currents on the terminals of the transmission line when it is...