**3.1 2D type EVC vibrator**

The EVC method is first proposed based on a 2D type EVC vibrator. Therefore, the research on 2D type EVC vibrator is relatively early and extensive. According to the principle of EVC, generally, there are two piezoelectric actuator configurations for the simplest: one is there existing an angle between two piezoelectric actuators, the other one is piezoelectric actuator parallel configuration. Shamoto and Moriwaki applied the vertical piezoelectric actuator configuration to achieve the EVC [5]. Cerniway [6] and Negishi [7] applied parallel piezoelectric actuator configuration to achieve the EVC. However, these non-resonant EVC vibrators have limited modulation ability and severe crosstalk. In recent years, the flexure-based non-resonant EVC vibrator has been developing rapidly. Here are some typical examples following below.
