Measurement of the scattering-parameters of planar multi-port devices

The measurement of the scattering parameters of multi-port devices with the help of a vector network analyzer (VNA) with two measurement ports is described. Besides a calibration of the VNA system a further error correction procedure has to be performed in order to eliminate the systematic errors caused by external terminations which have to be connected to the ports of the device under test (DUT) during the measurement of the scattering parameters with a two-port VNA. The application of the multi-port method is presented. This correction method has the advantages that the needed external terminations can be chosen arbitrarily. Furthermore, these terminations can be unknown except for one. An automatized measurement setup on the basis of a switching network optimized for the characterization of planar microstrip devices with four ports is presented. An error model for the description and a calibration procedure for the elimination of the systematic errors are depicted.