A Practical Method for Measuring Incident Microwave Power in RF Systems of Particle Accelerators

In high reflection microwave power measurements with load impedance mismatch, the limited directional performance of directional couplers introduces interference from reverse signals, which affects the accuracy of incident microwave power measurements. To address this issue, this paper will present a method that utilizes auxiliary circuits to change the amplitude and phase of the output signals from two directional couplers with lower directional performance and then combines them to cancel out the interference signal components. This microwave measurement method was validated on a 162.5‐MHz high‐power microwave experimental platform, reducing the maximum uncertainty in power measurement results from about ± 20% using a single directional coupler to −1.5%–3.5% adopting the proposed method in a standing wave cycle. This improvement was achieved by using two directional couplers with directional performances of 19.1 and 20.3 dB.