Control Method for Resonant Frequency of Cavity Resonance-Enabled WPT Using Reactance Probe

In this study, we propose a method for controlling the resonant frequency of a cavity resonance-enabled wireless power transfer using a reactance probe (RP), which involves inserting a monopole probe (MR) into the cavity and manipulating the reactance at its rear end. First, we demonstrate the relationship between the input impedance and frequency control achieved by mechanically adjusting the length of the MR. Subsequently, we separate the factors contributing to the frequency control by adjusting the LC element values in the reactance circuit (RC). Finally, we validate the resonant frequency control with a robot arm installed inside the cavity. When the robot arm is installed, the TE015 mode is 415.6 MHz. By setting the length of the MP to 180 mm and the RC element value to 68 pF, we successfully adjust the frequency to the desired transmission frequency of 417.5 MHz.