A New Principle for Measuring Electrical Length and Deviation from Linear Phase

This paper presents a unique way to measure the equivalent electrical length of a network as well as its deviation from linear phase. The measurement technique used is based upon a variable length transmission line simulator, built into the IF-structure of a 1.3 GHz Network Analyzer, but can be applied to higher frequencies. The new method allows to insert much more electrical length than the mechanical line stretchers do, without disturbing the measurement with additional mismatch errors. In addition to a calibrated readout of the equivalent electrical length in meters, the deviations from linear phase of a network can be presented very accurately in a real time swept display.