PMC

Pulse-echo response measurements and frequency spectra of 5.3 MHz and 20.0 MHz different-frequency transducers. (a) Echo response of a 5.3 MHz transducer; (b) frequency spectrum of a 5.3 MHz transducer; (c) photograph of the transducer of a 5.3 MHz transducer; (d) echo response of a 20.0 MHz transducer; (e) frequency spectrum of a 20.0 MHz transducer; and (f) photograph of the transducer of a 20.0 MHz transducer.

a 2D transducer model. b 3D-NIT transducer model. c 3D-IT transducer model. d In-plane patterns of the 2D and 3D-NIT transducer models. e In-plane pattern of the 3D-IT transducer model. f Out-of-plane structures of the 3D-NIT (top) and 3D-IT (bottom) transducer models

a In-plane pattern of the Square-4H transducer model. b In-plane pattern of the Square-NH transducer model. The corresponding simulated stationary temperature fields: c Top view of the Square-4H transducer model. d Top view of the Square-NH transducer model. e Cross-sectional view of the Square-4H transducer model. f Cross-sectional view of the Square-NH transducer model

Simulation results of the annular transducer: (a) transmission voltage response of the polymer phase doped PDMS annular transducer, (b) transmission voltage response of the polymer phase epoxy resin annular transducer, (c) directivity index of the polymer phase doped PDMS annular transducer, (d) the total sound pressure field of 160 kHz of the polymer phase doped PDMS annular transducer, (e) the total sound pressure field of 2500 kHz of the polymer phase doped PDMS annular transducer, and (f) the total sound pressure field of 400 kHz of the polymer phase doped PDMS annular transducer.