What is a Scalar Network Analyzer?

A Scalar Network Analyzer is a type of RF network analyzer that is used to measure only the amplitude properties of a DUT (Device Under Test). Unlike a Vector network Analyzer, it does not measure both amplitude and phase of the DUT.

They can be used to measure parameters like VSWR and Return loss, which only requires the measurement of the magnitude of a signal at a particular frequency or frequency range. In this case, we do not need to measure the phase.

A Scalar Network Analyzer can also be developed using a Spectrum Analyzer with a Tracking Generator. If both the Spectrum Analyzer and Tracking generator are operated at the same frequency and the output of the tracking generator is connected to the input of the spectrum analyzer, the spectrum analyzer will show a flat line on its screen to represent the output level of the tracking generator. Now if we place a device (DUT) between the tracking generator and the spectrum analyzer, the signal level we get at the spectrum analyzer will be a function of the DUT. Thus, we can calculate the amplitude properties of a device using a combination of a spectrum analyzer and tracking generator. This response can be calculated over a range of frequencies.

Over the last few years, we have seen the demand of SNA's decline. Keysight and Anritsu discontinued most (if not all) of their SNA products and now only develop VNA's. There are still a few companies who make SNA's.