The incident microwave power measurement in particle accelerator microwave systems

In high-reflection microwave power measurements with load impedance mismatch, the limited directivity of directional couplers introduces interference from reverse signals, affecting the accuracy of incident microwave power measurement. To address this issue, this paper presents a method that utilizes auxiliary circuits to adjust the amplitude and phase of the output signals from two directional couplers with lower directivity, combining them to cancel out the interference signal components. This microwave measurement method was validated on a 162.5 MHz high-power microwave experimental platform. The directivity of the new directional coupler measurement system, constructed using two directional couplers with directivities of 19.1 dB and 20.3 dB, reached 47.8 dB.