An ultrasound transducer with low synthetic quality factor, for in‐air applications, is presented. It is realized by curving a thin sheet of polyvinylidenefluoride and by assembling the so shaped piezo‐polymer film onto a mobile support. The resonance frequency, which is inversely proportional to the bending radius, can be easily varied on a range of some tens of kHz, 30–65 kHz, by mechanically controlling the opening arc angle of the curved film. An ultrasound transducer with both controlled resonance and controlled axial resolution is obtained. The combination of the different resonance frequencies, related to different opening angles, leads to a synthetic broad‐band transducer with unity quality factor Q. © 1996 American Institute of Physics.