Simplified broadband mm-wave pulsed VNA profiling measurements

Pulsed VNA measurements have long been used to characterize devices for isothermal or operational reasons and are increasingly needed at mm-wave frequencies for newer communications services. The ability to profile the device response over the pulse duration is also increasingly in demand to better understand transient behavior and to sometimes meet critical timing requirements. Traditional approaches, when implemented in these frequency ranges, are complicated by the bandwidth requirements on the modulators and the concomitant impact on uncertainties due to isolation or insertion loss. A simplified architecture is discussed wherein modulators are operating at lower frequencies. The limitations and benefits are discussed and illustrated with validation and amplifier measurements above 60 GHz.