A new type of radial composite piezoelectric ceramic transformer was proposed.Using the equivalent circuit method the radial vibration of the piezoelectric vibrator polarized in thickness direction and step metal structure were analyzed.The relationships between the ladder thickness ratio and the maximum voltage gain and the electromechanical coupling coefficient were obtained.Then the equivalent circuit of this new type of radial composite step disc piezoelectric ceramic transformer was derived. The analytical solutions of the input impedance, the resonance frequency, the anti-resonance frequency, the voltage gain and the power efficiency were obtained. The ANSYS simulation of resonance frequency verified the analytical results. The results show that the type of transformer got the most voltage gain under the resonance frequency, and obtained the most high power efficiency under the resonance frequency and the anti-resonance frequency. There was the best load for the voltage gain and the power efficiency.

piezoelectric transformer; radial vibration; equivalent circuit; resonance; voltage gain