ABSTRACT

One very useful instrument for studying high-frequency behavior of circuits is called the vector network analyzer; an example of one is pictured in Figure 1.1. Measurements can be made of impedance connected to either port 1 or port 2, or of the amount of signal gain and phase shift from one port to the other, when an amplifying or attenuating two-port is connected between the ports. One first selects a frequency range of interest between 0.3 and 3000 Mhz, and then calibrates the instrument for that range and for the type of measurement planned. As an example of what is possible, the machine was calibrated from 0.3 to 100 Mhz for measurements of the impedance connected to port 1. After calibration, a type N-to-BNC coaxial adapter was connected to port 1, and a BNC-to-binding-post adapter was connected to the first adapter, after which a nominal 47 pF capacitor was connected to the binding posts without shortening the original capacitor leads. The reactances measured are shown in Table 1.1.