Dual-Frequency Signal-Induced Multipactor Prediction for Parallel-Plate Waveguides Using the Mapping Curve Method

This study proposes a framework for predicting multipactor discharge between parallel metal plates driven by dual-frequency radio frequency (RF) signals. By transforming the composite waveform to obtain its envelope and instantaneous frequency, we map the dual-frequency excitation onto the multipactor susceptibility diagram as a characteristic curve. The multipactor assessment is performed by analyzing two factors: the distribution features of the mapping curves and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{p}$</tex-math> </inline-formula>. The distribution features are defined by the bending direction of the curves and their relative positions within the susceptibility diagram, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{p}$</tex-math> </inline-formula> is defined as the ratio of half-wave peaks that exceed the multipactor region boundary to the total number of half-wave peaks within one envelope period. Multipactor discharge is suppressed when <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{p}$</tex-math> </inline-formula> exceeds the threshold value and is triggered when it falls below the threshold value. The assessment results were validated using Monte Carlo simulations in the time domain, confirming the predictive power of the method. By integrating dual-frequency signal decomposition with susceptibility diagram mapping, our method offers a computationally efficient tool for assessing multipactor risk in multitone RF systems.