A Traceable Measurement Method of Microwave Top Power for High Power Pulse Wave

A measurement method of microwave pulse top power is described in this paper, for radiofrequency (RF) large power measurement application. Comparing to conventional large power pulse measurement with directional coupler and peak power sensor, both measurement stability and repeatability are improved. Waveform distortion problem caused by directional coupler is eliminated by symmetric measurement setup of oscillator and device under test (DUT). Thereby duty cycle could be accurately obtained in high-speed oscillator. Pulse top power is determined by microwave average power measured in flow calorimeter, which is further traced to low frequency (LF) power standard. Pulse top power measurements include both pulse signal generator with 10mW peak power level in small power condition, and pulse power amplifier with 1kW peak power output in large power condition. Measurement stability is dramatically improved by a reduction of standard deviation in top power measurement from 2% (directly measured by peak power sensor) to 0.2% (measured by proposed setup using flow calorimeter).