New calibration method for a 7-port reflectometer

The first prototype of a real-time swept-frequency network analyser using two 7-port reflectometers for general use in the microwave laboratory has been reported. It can make simultaneous measurements of all four S parameters of a 2-port device. The instrument relies on a calibration of the multiport reflectometers with an effective method which requires a minimum of standards and is mainly independent of frequency. The success of the prototype instrument is partly due to a novel calibration procedure, which exploits the additional information given by using the 7th port, and uses three frequency-independent standards along with one other approximately known termination.