Electromechanical equivalent circuit of radial composite ultrasonic transducer with a conical profile

A kind of radial composite ultrasonic transducer with a conical profile was studied.The transducer is composed of a metal ring with an equal section,an axially polarized piezoelectric ceramic ring and a metal ring with a conical profile and the radial dimension of the transducer is much larger than the height.The metal ring with a conical profile satisfies the equation h=h_(0)r,and h_(0) is a constant.Based on the plane stress radial vibration theory,the electromechanical equivalent circuit of the transducer was derived,the resonance frequency equation and anti-resonance frequency equation were obtained.And then the vibration characteristics of the transducer were studied.The first-order,second-order radial resonance frequencies and anti-resonance frequencies calculated by theory were compared with the numerical simulation results,and the results were consistent.The studies show that the first-order,second-order radial resonance frequencies and anti-resonance frequencies,and effective electromechanical coupling coefficients of the transducer with a conical profile are not only related to the material and radial geometry of each part of the transducer,but also to h_(0).As h_(0) increases,the first-order radial resonance frequencies and anti-resonance frequencies increase,and the effective electromechanical coupling coefficient first increases and then decreases.The transducer with a conical profile radiates sound waves radially outward.Compared with a transducer with an equal profile,the transducer with a conical profile has a larger radiation area,higher radiated sound power,and better directivity.