Scanning Head with 128-Element 20-MHz PVDF Linear Array Transducer

A scanning head has been designed and fabricated that incorporates a 20-MHz, 128-element linear transducer. The scanning head also incorporates -200 V pulsers and a custom 16-channel amplifier. The transducer was constructed with 28 μm PVDF film with an element pitch of 250 μm. The transducer showed an average -20 dB pulse length of 69 ns. The elements of the PVDF array were tested and found to have 7.5 mPa/√Hz equivalent noise pressure. The radiated power level for 32 pulsed elements was ~1 MPa. An imaging test shows that the system achieves axial and lateral resolutions of 40 μm and 0.2 mm, respectively. The entire scanning head dissipates ~1.6 W at a pulse repetition rate of 750 Hz.