Analysis of modern techniques for automatic measurements in microwaves

The analysis of modern techniques used for automatic measurements in microwaves is given in the paper. The advantages and drawbacks of two mainstream automatic network analyzers are discussed. The conventional measuring technique based on vector voltmeter (VV) is very accurate, so it is taken as a basis of almost all commercially available meters. However, it is based on the frequency down conversion; therefore, these meters include a large amount of expensive equipment, since they are very complicate and expensive. The second method of multi-port reflectometer (MPR) uses the power detectors for measurement of the output signals. Theoretically the equipment of this method is less complicated and expensive. But the calibration of the MPR is very difficult since it requires a large kit of precisely known standards that are available only for a few instrumentation engineers. That is why MPR did not are not widely used and are not commercially available. The special case of MPR is the multi-probe transmission line reflectometer (MTLR), which accuracy is less, but it can be precisely calibrated without any exactly known calibration standard. So, we put forward the idea of the combined MPR use. It consists of the conventional MPR being connected to MTLR. This structure can be calibrated without known standards and its accuracy is higher than the accuracy of the conventional MPR. Moreover, it becomes possible to unify the methods of VV and combined MPR, making the resulted meter less expensive and more accurate. The advantages of combined MPR are discussed.