PVDF - Polyvinylidene Fluoride

[Rickard]

Hi,

Is there anyone who has some experiance from using PVDF for underwater sonar applications? The material seems very practical to work with for an amatuer but it also seems to have some drawbacks like low transmit energy and wide bandwidth. My plan would be to build a sidescan transducer for a fishfinder using a combination of a conventional ceramic transducer for transmitting and an array cut from PVDF for receiving. This would result in very good energy properties of the system. But the broad bandwidth of PVDF worries me. I think this can let noise at other frequencies than the transmitted frequency into the system. Perhaps there is some frequency filter at the receive end inside fishfinders but that's hard to see from outside those "black boxes".

Rickard

[Rickard]

Old (new?) subject.

After some (long) time I give this issue another try. PVDF is the piezo electric material for the future, has anyone accomplished any progress in designing his/her own transducer using this type of material? I am one of those lucky persons who owns a Humminbird sideimaging sonar, but I really wish I could get a transducer with significantly better horizontal resolution for my instrument. I have seen statements saying PVDF is easy to cut in a shape that provides physical shading (I know what shape that would be). According to a very authoritive source at Humminbird, shading is the only way to accomplish better images with a long transducer. Problem is, PVDF is a bad transmitter so either the shape of the sheet must be modified in some way, or transmitting must be done with conventional PZT elements.

Any comments are most welcome.

Rickard