Implementation of an Oscilloscope Vector Network Analyzer for Teaching S-Parameter Measurements

In this paper, the feasibility of the use of a two- channel digital oscilloscope synthesized with a signal generator to create a two-port vector network analyzer (VNA) is experimentally validated. The sinusoidal transmitted and reflected signals are digitized by the oscilloscope and the data displayed is used to calculate the S-parameters of a device under test (DUT). The hardware used in this system is a common low-spec oscilloscope, a signal generator, and a coupler. All of these can be found or built in a classroom setting and can be used to demonstrate network analysis for education of students instead of using commercial VNAs which are expensive. The measured S-parameters gathered in this setup is within 4 decibels in magnitude and 20 degrees in phase compared to measurements on a commercial VNA.