The vector network analyzer itself has a signal generator that can scan a frequency band. If it is a single port measurement, the excitation signal is applied to the port. By measuring the amplitude and phase of the reflected signal, you can The impedance or reflection is judged. For the two-port measurement, the transmission parameters can also be measured. Since the influence of the distributed parameters is obvious, the network analyzer must be calibrated before use.
The network analyzer is a new type of instrument for measuring network parameters. It can directly measure the complex scattering parameters of active or passive, reversible or irreversible dual-port and single-port networks, and give the amplitude and phase of each scattering parameter in frequency sweep mode. Frequency characteristics. The automatic network analyzer can correct the measurement results point by point and convert other dozens of network parameters, such as input reflection coefficient, output reflection coefficient, voltage standing wave ratio, impedance (or admittance), attenuation (or gain). Transmission parameters such as phase shift and group delay, as well as isolation and orientation.
The network analyzer was developed on the basis of a four-port microwave reflectometer (see standing wave and reflection measurements). In the mid-1960s, automation was realized, and the error caused by the directionality of the directional coupler, mismatch, mismatch, and leakage was corrected at each frequency point by using a computer with a certain error model, so that the measurement accuracy was greatly improved. The measurement accuracy of the most sophisticated measuring line technology in the measuring chamber can be achieved, and the measuring speed is increased by several times.