Ultraprecise Resonant Frequency Prediction of Microwave Cavities With Deformations

A novel method is proposed to precisely predict the quantitative effect of geometric deformation on the resonant frequency offset of microwave cavity systems using explicit expressions. The analysis is not limited to any specific cavity shapes or certain forms of deformation, which indicates a wide application prospect of our method. The accumulative effect of electric and magnetic fields during the deformation process is observed here for the first time and taken into account to achieve an ultrahigh estimation precision beyond that of the traditional perturbation theory. The proposed method is assessed by analyzing a rectangular and a re-entrant cavity resonator as demonstration examples. The simulation and experimental results illustrate that the estimation errors based on the proposed method are the smallest compared to those reported by reference studies. For 16 sets of geometric deformations applied to the actual re-entrant cavity, the proposed method reduced the total error by 17.64 times.