Wavelet Transform Algorithm for Eigenfrequency Detection in a Piezoelectric Parity-Time Symmetric System

Piezoelectric resonant sensors that incorporate a parity-time (PT) symmetric structure have the potential to achieve enhanced sensitivity, particularly when exposed to asymmetric small disturbances at the exceptional point (EP). However, in such cases, the rapid splitting of the real part of the characteristic frequency is accompanied by an expansion of the reflection spectrum, resulting in a decrease in resolution due to the corresponding imaginary part. Therefore, accurately detecting the characteristic frequency becomes challenging, further limiting the performance of the sensors. This study addresses this limitation by employing the wavelet ridge peak detection technique to identify the characteristic frequency. The results demonstrate a lower loss rate in awakening peak and higher accuracy in peak detection. The technique can be used to improve the sensitivity resolution of PT symmetric sensors under asymmetric disturbances.