Overview

Radar systems, most of which employ pulsed signals, require a unique set of measurements, and their signals are not often easy to generate or analyze. However, there are specific techniques, from signal generation to network and spectral analysis that when properly applied make characterization of devices with pulsed signals easier and more repeatable and accurate. This Application Note describes these measurement scenarios, with emphasis on measurements using vector network analyzers (VNAs), signal generators, vector signal generators, and spectrum analyzers. The goal is to provide basic information on both the measurements and the equipment used to make them in terms that designers will find useful.

Measuring Pulsed Signal Devices with Vector Network Analyzers and Signal Generators

In many cases, devices must be characterized by using pulsed signals instead of CW signals, either by being stimulated with a pulsed RF signal or a pulsed control voltage. For example, during on-wafer measurements of power amplifiers, heat sinks are difficult or even impossible to implement, and by using pulsed stimulus signals, S-parameters can be measured at the power levels to which the devices will be subject in their intended use without exceeding a power level that could destroy them. By using an appropriate duty cycle, the average power can be reduced significantly while maintaining a high peak power. In addition, components designed for use in radar systems exhibit their desired performance only under pulsed stimulus conditions.